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CIRCUMFERENTIAL ACOUSTICSCANNING TOOL
(CAST-V)
SERVICE MANUAL
July 1997
Revision NW
Manual No. 770.00696
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Notices
All information contained in this publication is confidential and proprietary property of
Halliburton Energy Services, Inc. Any reproduction or use of these instructions,
drawings, or photographs without the express written permission of an officer of
Halliburton Energy Services, Inc. is forbidden.
© Copyright 1997 Halliburton Energy Services, Inc.
All Rights Reserved.
Printed in the United States of America
The drawings in this manual were the most recent revisions and the best quality availableat the time this manual was printed. We recommend that you check your manual for
individual drawing clarity and revision level. Should you have equipment with revisions
later than the drawings in this manual, or should you require higher quality drawings
than the drawings in this manual, order replacements from the Engineering Print Room
in Houston.
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07/97 770.00696-NW Revision Record
Revisions
Revision Record
Circumferential Acoustic Scanning Tool (CAST-V)
Service Manual
Date Description
07/97 Initial manual release (NW).
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HALLIBURTON ENERGY SERVICES Manual No. 770.00696
Technical Communications - Houston Circumferential Acoustic Scanning Tool
P.O. Box 42800 (CAST-V)
Houston, Texas 77242-8034 Service Manual
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improvement.
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02/99 770.00696-NW Table of Contents i
Contents
Table of Contents
General Information...............................................................................1-1
Introduction............................................................................................................................................... 1-1Equipment Description ............................................................................................................................. 1-2
Top Assembly Drawings .................................................................................................................... 1-2
Major Assembly Drawings................................................................................................................. 1-2
Equipment List ................................................................................................................................... 1-4
Specifications ............................................................................................................................................ 1-5
Mechanical.......................................................................................................................................... 1-5
Electrical............................................................................................................................................. 1-5
Measurement ...................................................................................................................................... 1-5
Image Mode ................................................................................................................................. 1-5
Cased-Hole Mode ........................................................................................................................ 1-6
Safety......................................................................................................................................................... 1-6
Personal Safety................................................................................................................................... 1-6
Equipment Safety ............................................................................................................................... 1-6
Theory of Operation...............................................................................2-1
Introduction............................................................................................................................................... 2-1
Nature of the Measurement....................................................................................................................... 2-1
Physical Principles.............................................................................................................................. 2-1
Acoustic Waveforms .......................................................................................................................... 2-4
Tool Processing: Window Sum and Thickness .................................................................................. 2-5
Transit Time Calculations .................................................................................................................. 2-6
Acoustic Impedance ........................................................................................................................... 2-7
Directional Measurements.................................................................................................................. 2-7
Functional Description......................................................................................................... ................... 2-10
System Functions.............................................................................................................................. 2-10
Automatic Gain Control............................................................................................................. 2-10
Outputs: Scan Data Formats ...................................................................................................... 2-11
Slow Channel Data Acquisition................................................................................................. 2-12
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ii Table of Contents 770.00696-NW 02/99
Inputs: Tool Commands............................................................................................................. 2-12
Scanner Assembly ( Drawing 707.55531)........................................................................................ 2-13
Description ................................................................................................................................. 2-13
Block Diagram ........................................................................................................................... 2-15
Transducers................................................................................................................................ 2-16
Directional Sub (Drawing 707.55572) ............................................................................................. 2-17
Description ................................................................................................................................. 2-17
Block Diagram ........................................................................................................................... 2-18Electronics Cartridge (Drawing 707.55598) .................................................................................... 2-19
Description ................................................................................................................................. 2-19
Block Diagram ........................................................................................................................... 2-19
Circuit Descriptions ................................................................................................................................ 2-23
Remote Telemetry Unit RTU-B (Drawing 3.85601) ....................................................................... 2-23
V40 CPU Board (Drawing 707.55666) ............................................................................................ 2-24
Commutator Board (Drawing 707.55559) ....................................................................................... 2-26
Circuit Description............................................................................................................ ......... 2-26
Compass Board (Drawing 707.55574) ............................................................................................. 2-28
Power.......................................................................................................................................... 2-28
Saturable Inductor...................................................................................................................... 2-28Circuitry ..................................................................................................................................... 2-30
Oscillator-Driver.............................................................................................................. .... 2-30
Sense Amplifiers ................................................................................................................. 2-30
Measurement Calculations......................................................................................................... 2-32
Factory Adjusts .......................................................................................................................... 2-32
Data Acquisition Board (Drawing 707.41002) ................................................................................ 2-33
Gain Control............................................................................................................................... 2-33
Reference Voltage.............................................................................................................. ........ 2-34
ADC ........................................................................................................................................... 2-34
Preamplifier/Fire Board (Drawing 707.55668) ................................................................................ 2-34
Generation Of The Ultrasonic Pulse .......................................................................................... 2-35
Recovering the Return Signal .................................................................................................... 2-36
Auxiliary Circuitry............................................................................................................ ......... 2-39
CAST-V Power Circuitry ................................................................................................................. 2-39
Circuit Description............................................................................................................ ......... 2-39
Instrument Power................................................................................................................. 2-40
Startup.................................................................................................................................. 2-42
Inverter ................................................................................................................................ 2-42
Preregulator ......................................................................................................................... 2-43
400-Vdc Circuitry................................................................................................................ 2-43
Motor Voltage............................................................................................................................ 2-44
R-to-D Board (Drawing 707.55561) ................................................................................................ 2-44
Circuit Description............................................................................................................ ......... 2-44Slow ADC Board (707.55587) ......................................................................................................... 2-47
Circuit Description............................................................................................................ ......... 2-48
Analog Circuitry.................................................................................................................. 2-48
Reference Voltage ............................................................................................................... 2-48
Negative 5-Vdc.................................................................................................................... 2-48
Input Selector....................................................................................................................... 2-48
Buffer................................................................................................................................... 2-49
Digital Circuitry ......................................................................................................................... 2-49
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02/99 770.00696-NW Table of Contents iii
Strobe................................................................................................................................... 2-49
Counters............................................................................................................................... 2-49
EPLD ................................................................................................................................... 2-50
Internal Calibration.............................................................................................................. 2-51
RS-232 Data Output................................................................................................................... 2-51
Data Output.......................................................................................................................... 2-51
Output Waveform................................................................................................................ 2-52
Disassembly and Assembly..................................................................3-1
Introduction............................................................................................................................................... 3-1
Tools And Equipment Required ............................................................................................................... 3-1
Basic DITS Disassembly .......................................................................................................................... 3-2
Electronics and Directional Sub ......................................................................................................... 3-2
Basic DITS Assembly............................................................................................................................... 3-4
Electronics and Directional Sub ......................................................................................................... 3-4
Disassembly of the Cast-V Scanner.......................................................................................................... 3-5Reference Drawings ........................................................................................................................... 3-5
Oil Drain............................................................................................................................................. 3-5
Transducer Holder Removal...................................................................................................... ......... 3-5
Face Seal Removal ............................................................................................................................. 3-6
Housing Disassembly ......................................................................................................................... 3-6
Mud-Cell Removal ............................................................................................................................. 3-6
Motor Assembly Removal.................................................................................................................. 3-6
Slip-Ring Removal ............................................................................................................................. 3-6
Shaft and Bearing Removal................................................................................................................ 3-7
Assembly of the Cast-V Scanner .............................................................................................................. 3-7
Motor-Resolver Assembly........................................................................................................ .......... 3-7
Motor Mount Assembly ..................................................................................................................... 3-8
Shaft Assembly................................................................................................................................... 3-8
Slip-Ring Installation......................................................................................................... ................. 3-8
Face Seal Installation......................................................................................................... ................. 3-9
Keyed Sub and Motor Housing Assembly ....................................................................................... 3-10
Mud-Cell Assembly.......................................................................................................................... 3-10
Pressure Balance Assembly...................................................................................................... ........ 3-11
Motor Assembly and Keyed Housing Assembly ............................................................................. 3-12
DITS Upper Sub Assembly ........................................................................................................ ...... 3-12
Holder and Transducer Assembly .................................................................................................... 3-13
Oil-Fill Procedure ................................................................................................................................... 3-13
Pressure and Temperature Test ............................................................................................................... 3-14
Adjustment of the Motor/Resolver Assembly ........................................................................................ 3-15
Equipment Required......................................................................................................................... 3-15
Reference Drawings ......................................................................................................................... 3-15
Procedure.......................................................................................................................................... 3-15
Fixed Position Alignment .......................................................................................................... 3-17
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iv Table of Contents 770.00696-NW 02/99
Electrical Zero Alignment.......................................................................................................... 3-18
Calibration and Verification ..................................................................4-1
Introduction............................................................................................................................................... 4-1
Calibration of the Directional Sub ............................................................................................................ 4-1
General................................................................................................................................................ 4-1Equipment........................................................................................................................................... 4-2
Magnetometer Adjustment ........................................................................................................ ......... 4-2
Adjustment Procedure........................................................................................................... ....... 4-5
Recheck of Magnetometer Adjustment ....................................................................................... 4-8
Inclinometer Adjustment........................................................................................................ ............ 4-9
Adjustment Procedure........................................................................................................... ....... 4-9
Quality Control Data Collection (And Temperature Testing)............................................................ 4-9
Page 1, Data Sheet Instructions ................................................................................................... 4-9
Page 2, Data Sheet Instructions ................................................................................................... 4-9
Directional Sub Check ............................................................................................................................ 4-14
Test Stand Setup............................................................................................................................... 4-14Installing The Directional Sub Chassis...................................................................................... 4-15
Magnetometer Check........................................................................................................................ 4-15
Inclinometer Check .......................................................................................................................... 4-16
Troubleshooting.....................................................................................5-1
Introduction............................................................................................................................................... 5-1
Required Equipment ................................................................................................................................. 5-1
CAST-V Testing ....................................................................................................................................... 5-2
Resistance Tests.................................................................................................................................. 5-2
Power Supply (Drawing 707.50606).................................................................................................. 5-3
Setup Procedure ........................................................................................................................... 5-4
Power Supply Adjustment ........................................................................................................... 5-5
Parallel/Serial RTU-B Board (Drawing 3.85601) .............................................................................. 5-6
Setup Procedure ........................................................................................................................... 5-6
Troubleshooting ........................................................................................................................... 5-6
R-to-D Board (Drawing 707.55561) .................................................................................................. 5-7
Setup Procedure ........................................................................................................................... 5-7
Troubleshooting ........................................................................................................................... 5-7
Commutator Board (Drawing707.55559) .......................................................................................... 5-7
Setup Procedure ........................................................................................................................... 5-8
Troubleshooting ........................................................................................................................... 5-9V40 CPU Board (Drawing 707.55666) .............................................................................................. 5-9
Setup Procedure ........................................................................................................................... 5-9
Slow ADC Board (Drawing 707.55587) .......................................................................................... 5-10
Setup Procedure ......................................................................................................................... 5-10
Troubleshooting ......................................................................................................................... 5-11
Preamplifier/Fire Board (707.55668) ............................................................................................... 5-11
Setup Procedure ......................................................................................................................... 5-12
Troubleshooting ......................................................................................................................... 5-13
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02/99 770.00696-NW Table of Contents v
Data Acquisition Board (Drawing 707.41002) ................................................................................ 5-14
Setup Procedure ......................................................................................................................... 5-14
Troubleshooting ......................................................................................................................... 5-14
Acquisition Control and DSP Board (Drawing 707.55665)............................................................. 5-15
Setup Procedure ......................................................................................................................... 5-15
Gain-Range Testing.......................................................................................................................... 5-16
Test Procedure............................................................................................................................ 5-16
Heat Test and QC Data Collection ................................................................................................... 5-19Procedure ................................................................................................................................... 5-19
References .............................................................................................6-1
Introduction............................................................................................................................................... 6-1
Manuals..................................................................................................................................................... 6-1
DITS CAST Tool Upgrade to the CAST-V.............................................................................................. 6-1
Reference Drawings ........................................................................................................................... 6-1
General Information ........................................................................................................................... 6-2
Transformer Identification ................................................................................................................. 6-2Upgrade Procedure ............................................................................................................................. 6-2
Resistance Measurements ................................................................... A-1
Introduction...............................................................................................................................................A-1
Downhole End Resistance Measurements ................................................................................................A-1
Uphole End Resistance Measurements.....................................................................................................A-3
CAST-V PC Monitor Program ............................................................... B-1
Introduction...............................................................................................................................................B-1
Required Equipment .................................................................................................................................B-1
Operation...................................................................................................................................................B-1
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vi Table of Contents 770.00696-NW 02/99
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02/99 770.00696-NW List of Figures vii
Figures
List of Figures
Figure 1-1: CAST-V Tool......................................................................................................................... 1-3
Figure 2-1: Transducer Model .................................................................................................................. 2-2
Figure 2-2: Pressure Waves 14 µs After Firing........................................................................................ 2-2
Figure 2-3: Pressure Waves 24 µs After Firing........................................................................................ 2-3
Figure 2-4: Pressure Waves 29 µs After Firing........................................................................................ 2-3
Figure 2-5: Pressure Waves 37 µs After Firing........................................................................................ 2-4
Figure 2-6: Voltage Waveform, Open Hole........................................................................................ ...... 2-5
Figure 2-7: Voltage Waveform, Cased Hole ............................................................................................ 2-5
Figure 2-8: Azimuth and Relative-Bearing Diagram................................................................................ 2-8
Figure 2-9: Cased-Hole Waveform......................................................................................................... 2-10
Figure 2-10: CAST-V Scanner................................................................................................................ 2-14
Figure 2-11: CAST-V Scanner Block Diagram...................................................................................... 2-15
Figure 2-12: CAST-V Transducer .......................................................................................................... 2-16
Figure 2-13: CAST-V Directional Sub ................................................................................................... 2-17
Figure 2-14: Directional Sub Block Diagram..................................................................................... .... 2-18
Figure 2-15: Electronics Block Diagram ................................................................................................ 2-19
Figure 2-16: DSP Block Diagram........................................................................................................... 2-20
Figure 2-17: V40 Telemetry CPU Block Diagram ................................................................................. 2-21
Figure 2-18: Waveforms from a Commutator Board ............................................................................. 2-27
Figure 2-19: Saturable Reactor Flux Diagram......................................................................................... 2-28
Figure 2-20: Analog Waveforms from a Compass Board........................................................................ 2-29
Figure 2-21: Gate Timing versus Saturation Curve.................................................................................. 2-31
Figure 2-22: Fire-Pulse............................................................................................................................ 2-36
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viii List of Figures 770.00696-NW 02/99
Figure 2-23: Gain and Frequency Response Curves ................................................................................ 2-38
Figure 2-24: CAST-V Power Circuitry Block Diagram ......................................................................... 2-41
Figure 2-25: Waveforms from the Oscillator and Resolver Transformer .............................................. 2-45
Figure 2-26: Amplitude Modulation Resulting from Rotation of the Scanner ......................................... 2-46
Figure 2-27: Timing Relationships of STROBE, CAL, and HOLDNOT............................................... 2-50
Figure 2-28: Timing Relationships of STROBE, CAL, and RS-232 Output............................................ 2-53
Figure 3-1: Removing the DITS Connector from the Pressure Housing.................................................. 3-3
Figure 3-2: Installing the DITS Connector into the Housing ................................................................... 3-4
Figure 3-3: Piston Seals........................................................................................................................... 3-12
Figure 3-4: Piston Gage Position ............................................................................................................ 3-14
Figure 3-5: Setup Connections for Resolver Adjustment with the CAST Tool ..................................... 3-16
Figure 3-6: Setup Connections for Resolver Adjustment with the Simulator Board ............................. 3-16
Figure 3-7: Relationship of the Keyway to the Orientation Hole at Electrical Zero.............................. 3-17
Figure 3-8: Run Connections for the Motor with the CAST Tool.......................................................... 3-18
Figure 3-9: Run Connections for the Resolver Setup with the Simulator Board ................................... 3-19
Figure 4-1: Test Stand Setup................................................................................................... .................. 4-3
Figure 4-2: Test Setup Wiring .................................................................................................................. 4-4
Figure 4-3: Gate Timing Relationships on the Compass Board ............................................................... 4-6
Figure 4-4: Signal Waveforms on the Compass Board. ........................................................................... 4-7
Figure 4-5: Vertical Stand Position......................................................................................................... 4-14
Figure 4-6: Stand Position for 90-Degree Inclination ............................................................................ 4-16
Figure 4-7: Stand Position for 5-Degree Inclination .............................................................................. 4-17
Figure 5-1: Bench Test Wiring Diagram .................................................................................................. 5-2
Figure 5-2: Block Diagram of the Cast-V Power Supply ......................................................................... 5-3
Figure 5-3: Load Resistances for Power Supply Testing.......................................................................... 5-4
Figure 5-4: Waveforms from Commutator Board FET Drains ................................................................ 5-8
Figure 5-5: Stand Test Target Setup (distances in in.) ........................................................................... 5-12
Figure 5-6: Fire-Pulse Waveform ................................................................................................ ........... 5-13
Figure 5-7: Gain Test Setup .................................................................................................................... 5-17
Figure 5-8: Oven Test Setup ................................................................................................................... 5-21
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02/99 770.00696-NW List of Figures ix
Figure 6-1: Toroid Winding...................................................................................................................... 6-3
Figure 6-2: Wiring of Modified Transformer ........................................................................................... 6-4
Figure B-1: PC Monitor Program Main Menu ....................................................................................... ..B-2
Figure B-2: Waveform Data for Openhole Mode.....................................................................................B-3
Figure B-3: Waveform Data for Cased-Hole Mode .................................................................................B-6
Figure B-4: Scan Data for Openhole Mode ........................................................................................ ......B-7
Figure B-5: Scan Data For Cased-Hole Mode...................................................................................... ....B-8
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x List of Figures 770.00696-NW 02/99
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06/96 770.00696-NW List of Tables xi
Tables
List of Tables
Table 1-1: CAST-V Tool Primary Components ...................................................................................... . 1-4
Table 1-2: Additional Equipment ............................................................................................................. 1-4
Table 2-1: Tool Data Scan Format............................................................................................... ........... 2-11
Table 2-2: Slow Channel Auxiliary Data................................................................................................ 2-12
Table 2-3: Input Select and First-Stage Gain Control ............................................................................ 2-37
Table 2-4: Second-Stage Gain Control ................................................................................................... 2-37
Table 2-5: CAST-V Power Conductor-to-Pin Identification.................................................................. 2-39
Table 2-6: Sequence of Bits Transmitted................................................................................................ 2-51
Table 5-1: Parameters in the V40 CPU Slow-Channel Data Processing................................................ 5-10Table 5-2: Slow ADC Voltage Reference............................................................................................... 5-11
Table 5-3: Gain Test, Increasing Attenuation and Decreasing Amplitude............................................. 5-17
Table 5-4: Gain Test, Decreasing Attenuation and Increasing Amplitude............................................. 5-18
Table 5-5: Gain Test, Mud-Cell Channel......................................................................................... ....... 5-18
Table A-1: Downhole End Resistance Measurements..............................................................................A-1
Table A-2: Uphole End Resistance Measurements ..................................................................................A-3
Table B-1: Tool Commands of the CAST-V PC Monitor Program .........................................................B-1
Table B-2: Tool Parameters of the CAST-V PC Monitor Program..........................................................B-4
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Halliburton Energy Services
07/97 770.00696-NW General Information 1-1
General Information
IntroductionThis technical manual provides the theory of operation and maintenance for the
Circumferential Acoustic Scanning Tool (CAST-V). Study the manual closely to
develop a thorough understanding of the tool before operating or servicing the tool for
the first time. Observe all precautionary notes to minimize the risk of personal injury or
damage to equipment.
Tabbed sheets physically divide the manual into six sections and two Appendices.
Section 1, General Information, discusses the scope and arrangement of the manual,
describes the tool and explains its purpose, lists equipment specifications, and provides
safety information.
Section 2, Theory of Operation, presents the principles of operation of the CAST-V. A
functional description of the hardware accompanied by block diagrams and detailed
circuit descriptions is included.
Section 3, Disassembly and Assembly, contains step-by-step disassembly and assembly
procedures for the CAST-V. A list of tools and equipment required to disassemble and
assemble the CAST-V is provided.
Section 4, Calibration and Verification, contains both hardware and software procedures
for the CAST-V. A list of tools and equipment required to perform shop and field
calibration or verification of the CAST-V is provided.
Section 5, Troubleshooting, contains a series of circuit checks complete with
corresponding values (voltage, resistance, and others). These checks are provided to help
isolate electrical and electronic faults to a repairable level. A list of test equipment and
the appropriate setup is provided.
Section 6, References, contains material that may be helpful during operation,
maintenance, and troubleshooting of the CAST-V.
Appendix A, Resistance Measurements, contains resistance values for the uphole and
downhole ends for the CAST-V Electronics Chassis.
Appendix B, CAST-V PC Monitor Program, contains information for sending tool
commands and monitoring tool data without a surface system. A list of equipment is
provided.
Section
1
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1-2 General Information 770.00696-NW 07/97
Equipment DescriptionThe Circumferential Acoustic Scanning Tool (Figure 1-1) is an ultrasonic tool designed
to provide high-resolution images in both cased and open boreholes. The tool contains a
high-frequency acoustic transducer that rotates in an interchangeable head at the bottom
of the tool. A second acoustic transducer is mounted in the scanner housing and is used
to measure characteristics of the borehole fluid. A directional sub is provided to orient
images to either the high side of the hole or to north. Images consist of 200 points
horizontally by 40 samples per foot vertically in the image mode and 100 points by 4
samples per foot in the cased-hole mode. The CAST-V is a DITS tool designed to
operate on multiconductor cables in trucks with the EXCELL 2000 series surface
systems.
In both cased-hole and image modes, the system can provide high-resolution images
indicating texture changes in the borehole wall or casing. Images provided by the higher
resolution image mode can be used to identify fractures or to find defects in casing. The
cased-hole mode is used primarily to determine cement bonding and to image channels
in the cement directly behind the casing. Images can be oriented to either the tool body
or the high side of the hole in any operating mode. Open-hole images can be oriented to
north using an internal compass.
The CAST-V tool must be run centralized in fluid-filled boreholes. It must be the bottom
tool in any combination. Its operation is limited by factors such as high mud density and
dissolved gasses that increase the attenuation of the tool’s acoustic pulses as they travel
through the borehole fluid.
Top Assembly Drawings
The CAST-V top assembly drawing number is 707.55600.
The DITS CAST tool upgrade to CAST-V is 707.55650
Major Assembly Drawings
The CAST-V major assemblies and their drawing numbers are listed below. Tables 1-1
and 1-2 show the primary components, additional equipment, and part numbers.
• Electronics Assembly (Instrument Section), 707.55598
• Electronics Assembly (DITS CAST Upgrade to CAST-V), 707.55567
• Directional Sub Assembly, 707.55572
• Scanner Assembly, 707.55531
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07/97 770.00696-NW General Information 1-3
Figure 1 -1: CAST-V Tool
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1-4 General Information 770.00696-NW 07/97
Equipment ListTable 1 -1: CAST-V Tool Primary Components
DESCRIPTION PART
CAST-V Tool 707.55600
CAST-V Instrument 707.55598
CAST-V Directional Sub 707.55572
CAST-V Scanner 707.55531
CAST-V Transducer Heads
3-5/8 in. head assembly 707.55525
4-3/8-in. head assembly 707.55542
5-5/8-in. head assembly 707.55672
7-in. head assembly 707.55670
CAST-V Transducers
250-kHz cased-hole (white) 707.31495
350-kHz cased-hole (brown) 707.31449
450-kHz cased-hole (black) 707.31473
380-kHz openhole (brown focused face) 707.31408
Table 1 -2: Additional Equipment
DESCRIPTION PART
Oil Fill Gauge (used to check the Scanner oil fill) 707.55673
Chassis Insertion/Removal Tool, 3-5/8-in. DITS 3.30014
Thread Protector, Male, Standard DITS 3.29994
Thread Protector, Female, Standard DITS 3.29996
Calibration Stand Assembly 707.55635
DITS 19-Pin Breakout Box 3.48655
Spanner, 3-5/8-in. Standard DITS 0.96655
CAST-V Service Manual (order through Records andSupply in Houston, TX)
770.00696
Fanfold Paper 770.10577
Engineering Documentation Package (EDP) 770.00710
DITS 37-Pin Jumper Cable 3.48659
DITS 19-Pin Jumper Cable 3.48657
CAST-V Field Operations Manual - Image Mode 770.00700
CAST-V Field Operations Manual - Cased-Hole 770.00709
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Click here for the current Tool Technical Specifications data sheet. - Cased-Hole Mode
Click here for the current Tool Technical Specifications data sheet. - Imaging Mode
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07/97 770.00696-NW General Information 1-5
SpecificationsMechanical, electrical, and measurement specifications are included in this subsection.
Mechanical
• Maximum operating temperature: 350°F (177°C)
• Maximum operating pressure: 20,000 psi (137,900 kPa)
• Length: 17.9 ft (5.45 m)
• Diameter: 3-5/8 in. (9.2 cm)
• Electronics Assembly: 122.15 in. (3.1 m)
• Directional Sub Assembly: 36.5 in. (0.93 m)
• Scanner Assembly: 56.1 in. (1.43 m)
Electrical• 120 ±18 Vac, 60 Hz, 250 mA (W5)
• 150-Vdc, 1.5 A (Sorenson)
• Full load requirements: 30-Wac, 225-Wdc
Measurement
This subsection contains the measurement accuracy specifications for the CAST-V in
image and cased-hole modes. The minimum and maximum borehole diameters in which
the tool will operate are included.
Image ModeSensor Type: Piezoelectric on rotating head
Firing Rate (shots/scan): 200
Vertical Scan Rate: 40 scans/ft at 21 ft/min
Telemetry System: Digital Interactive Telemetry System
Compatibility: DITS (requires up to 288 words/frame)
Principle: Ultrasonic Pulse Echo
Azimuthal Sampling: 1.8°
Vertical Sampling (Software): 0.2 in.
Logging Speed: 21 ft/min
Primary Curves: Reflected Amplitude and Travel Time
Secondary Curves: Radius, Azimuth, Relative Bearing, Deviation, andFluid Transit Time
Minimum Diameter Hole: 4.5 in. (11.4 cm)
Maximum Diameter Hole: 12.50 in. (31.75 cm)
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Cased-Hole ModeSensor Type: Piezoelectric on rotating head
Firing Rate (shots/scan): 100
Vertical Scan Rate: 4 scans/ft at 30 ft/min
Telemetry System: Digital Interactive Telemetry System
Combinability: FWST, CCL, NGRT, SDDT, and DSNT.
DITS (requires 48 words/frame)
Principle: Ultrasonic Pulse Echo
Azimuthal Sampling: 3.6°
Vertical Sampling: 6.0, 3.0, or 1.0 in.
Logging Speed: 60, 30, or 10 ft/min
Primary Curves: Reflected Amplitude, Radius, Acoustic Impedance,and Casing Wall Thickness
Secondary Curves: Deviation, Relative Bearing, Compressive Strength,Fluid Transit Time, and Mud Impedance
Minimum Diameter Hole: 5.5 in. (12.7 cm)
Maximum Diameter Hole: 13.375 in. (33.97 cm)
Safety
Personal Safety
Avoid electrical shock hazards. Disconnect power from the equipment before performing
maintenance and repairs.
Support the tool on dollies, sawhorses, workbenches, or other suitable tool supports
when servicing. Ensure that the tool is secured to the work surface to prevent it fromrolling.
Use the proper lifting technique when handling the CAST-V.
Equipment Safety
Use extreme caution when lifting the CAST-V Scanner Assembly. The Scanner’s motor
shaft can be easily bent or damaged if it is not handled properly. Lift and lower the
Scanner Assembly in the well separately from the CAST-V Electronic Assembly.
Use extreme care when handling the CAST-V transducers. These devices are sensitive to
shock and vibration. Avoid bumping or hitting these devices.Ensure that the CAST-V pressure-balance system contains oil to the proper level and that
the oil is contaminant-free after every logging job. Both contaminated oil or low oil
levels can cause severe damage to the tool even if the tool is operating in wells where the
temperature and pressure are within normal specifications. Contaminated oil and low oil
levels significantly reduce the operating temperature and pressure limits of the tool.
Do not exceed CAST-V pressure, temperature, or electrical limits during operation.
Do not “spud”; because damage to the motor shaft or face seal may occur.
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Halliburton Energy Services
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Section
2
Theory of Operation
IntroductionThis section contains a discussion of the tool in increasing detail. Areas discussed in this
section include:
• A basic discussion of how the tool makes the measurement.
• A hardware functional description of overall equipment operation supported by block
diagrams. The block diagrams show major functional blocks; a discussion follows
the block diagram.
• A block description which explains the major functions but not the circuits.
• A circuitry description section that discusses the circuitry for each of the major
functions of the assembly. To make complex assemblies easier to read andunderstand, some circuit discussions are broken down into simpler schematics and
discussions.
Nature of the MeasurementThe CAST-V tool measures characteristics of the borehole wall or casing using a high-
frequency pressure pulse. During operation, transmitted ultrasonic pulses interact with
the borehole wall in a way that causes pressure waves to travel back to the tool. The
transducer used to transmit the original pulse then converts these pressure variations to a
voltage waveform. The digitized values of this waveform are the basis for all CAST-V
images and curves in both cased and open boreholes.
Physical Principles
A model of a transducer placed approximately 1 in. from the inner wall of a 0.3-in. thick
casing is shown in Figure 2-1.
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Figure 2-1: Transducer Model
Images computed using a model show a magnified view of how pressure waves
propagate in the area around the model after the transducer is fired in a cased borehole
(See Figures 2-2 through 2-5). Borehole pressure variations are presented in cross section
as changes in intensity. Pressure waves are shown for both free pipe and bonded pipe at
four different time intervals after transducer firing.
Figure 2-2 shows the pressure waves at approximately 14 ps after transducer firing and
before they arrive at the casing. The active area of the transducer is approximately 2.5
water wavelengths wide, causing the circular wavefronts shown. The greatest pressure
intensities occur in a triangular region in front of the transducer.
Figure 2-2: Pressure Waves 14 ps After Firing
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Figure 2-3 is taken at approximately 24 us after transducer firing and just after the pulse
strikes the casing. The pressure amplitude in the zone behind the bonded casing is larger
than in free pipe as energy is transferred into the cement.
Figure 2-3: Pressure Waves 24 µs After Firing
Figure 2-4 shows the pressure waves traveling back to the transducer at approximately 29
ps after transducer firing. The curved wavefronts of the output waves have been changed
to flat ones because of the focusing effect of the casing. The wavelengths of the waves
behind the bonded casing are longer than those in free pipe because of the higher
acoustic velocity of cement relative to that of water.
Figure 2-4: Pressure Waves 29 µs After Firing
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In Figure 2-5, the reflected wavefronts arrive back at the transducer approximately 37 ps
after the initial transducer firing. The waves caused by the resonance ringing of the
casing follow behind the higher intensity reflected waves. This difference in amplitude
between the reflected and resonance waves is more than 10:1 and requires that the gain
be increased while the casing waveform is being recorded.
Figure 2-5: Pressure Waves 37 µs After Firing
From the figures, it is apparent that the resonance waves (the area behind the reflected
waves) in the free pipe are of higher intensity than those in bonded pipe. This amplitude
difference is the basis of the bonding measurement. Cased-hole resonance waves are of
lower amplitude and fade more quickly than those in free pipe. Waveform recordings
start when the transducer is fired and last for a time that ensures that all pressure
disturbances have faded in the area around the tool.
Acoustic WaveformsFigure 2-6 shows the voltage waveforms at the transducer caused by pressure variations
in the borehole fluid. The starting point of the time axis is the time that the initial pulse
is fired from the transducer. All images created by the CAST-V tool are made by various
characteristics of these waveforms.
Two raw CAST-V measurements are taken directly from the waveform. The reflected
pulse amplitude and the total time of a pulse’s trip from the transducer to the borehole
wall and back are made in all operating modes and are the only measurements made inimage mode. The peak amplitude is used to image the borehole without further
processing. Fairly small textural features of approximately 0.05 in. can cause a detectable
change in amplitude. The transit time, on the other hand, has much lower spatial
resolution, but it can be used with the fluid velocity measurement to observe changes in
distance from the transducer face to the borehole wall on the order of 0.01 in.
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Figure 2-6: Voltage Waveform, Open Hole
Tool Processing: Window Sum and ThicknessThe amplitude and transit time values are taken directly from acoustic waveforms and do
not require any further calculation by the tool itself. In the cased-hole mode, two
additional parameters are derived that do require processing. Downhole processing
reduces the amount of data sent uphole by a factor of 16:1.
All downhole calculations are made on a section of the waveform that starts 15 ps after
the initial parts of the reflection pulse arrive back at the transducer (Figure 2-7). This
delay allows most of the reflection to fade so that the majority of the signal is caused by
the vibrating casing. A period of 12.8 ps (64 ADC samples) are used in the measurement
window.
Figure 2-7: Voltage Waveform, Cased Hole
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The simplest calculation on the resonance window is to simply add the 64 individual
sample values. Negative values are converted to positive values before addition. This raw
sum is the basis for all bonding measurements made by the CAST-V. The smaller the
raw sum value, the greater the degree of bonding.
The thickness calculation is the second, more complex calculation made on the resonance
window. It is calculated from the resonance frequency of the casing and the velocity of sound in steel. For any wave motion, the velocity of propagation is equal to the product
of its wavelength and its frequency. Most of the energy of vibration in the resonance
window is assumed to come from the pipe’s fundamental mode of resonance, in which
the thickness of the casing is equal to twice the wavelength. If the velocity of
propagation in steel is 19,029 fps, the thickness can be calculated from the frequency of
the waveform using:
The CAST-V processor first makes an estimate of the resonance frequency using the
average transit time for the 100 shots in a single horizontal sweep. This average iscombined with the fluid acoustic velocity to determine the nominal internal diameter of
the pipe. The outer diameter of the pipe is entered at the surface and then downlinked to
the tool. The first thickness estimate is then just one half of the difference between the
inner and outer diameters. This thickness is converted to a frequency by the use of the
relationship above.
The first resonance frequency estimate is then refined with the Fourier transform. The
magnitude of the frequency transform is calculated at steps corresponding to 0.002-in.
thickness changes. Magnitudes are calculated until a peak is found. This frequency is
then converted to thickness and encoded for transmission uphole. Much of the computing
time required in the tool’s high-speed microcomputer is used in the thickness calculation.
Transit Time CalculationsThe distance to the borehole wall, hole radius, tool eccentering, casing ovality, and fluid
acoustic velocity values are all calculated from the transit time of the main and mud-cell
transducers. The distance image is the product of the transit time from the main
transducer and the fluid acoustic velocity from the mud-cell transducer. The radius image
is a distance image corrected for tool eccentering, in which the points of reference for the
distance measurements are transposed from the center of the tool to the center of the
hole. Tool eccentering is the maximum difference between any two distance values that
are 180° apart. Ovality is calculated using the maximum difference of any two diameter
measurements that are 90° apart.Fiuid acoustic velocity is calculated from the transit time of the mud-cell transducer.
This transducer always fires at a target 1.25 in. from the face of the transducer. Fluid
velocity is given by:
where Tm is the round-trip transit time of the mud-cell pulse.
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Acoustic ImpedanceThe apparent acoustic impedance of the material behind the casing is calculated uphole.
The value is obtained from the window sum value calculated by the tool. The sum is first
normalized to the amplitude of the reflected pulse to make a raw normalized sum value.
This step removes the effect of changes in fluid attenuation between shots.
The next step is to compare the normalized sum value at the point measured to that
observed in pipe bonded with a known impedance. Normally, this is totally unbonded
free pipe. This calibration step removes variations due to transducer sensitivity, casing
thickness, and casing size. The ratio value is used directly to calculate acoustic
impedance and is given by:
The value for the normalized sum at the calibration (cal) point can be obtained by
logging a section of free pipe, by obtaining measurements from a calibration fixture
containing the same size of casing as that being logged, or by mathematically modeling
the waveform expected at the cal point with the reflection waveform as an input.
The final step is to convert the calibrated ratio of normalized sums to acoustic
impedance. The relationship used is:
impedance in Mrayls = cal point impedance -10 x thickness x ln(ratio),
where thickness is in inches and the cal point impedance is 1.5 Mrayls in free casing with
water behind it.
Directional MeasurementsThe CAST-V tool includes a two-axis directional sub to orient acoustic images. The
surface software can also orient images with directional data from the SDDT. Figure 2-8
shows the orientation angles used in the CAST-V service.
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Figure 2-8: Azimuth and Relative-Bearing Diagram
The directional sub contains two sets of sensors. One set measures the direction of the
earth’s magnetic field. The other set measures the earth’s gravity. Both measurements are
made in a plane perpendicular to the tool chassis and are referenced to the DITS
interconnection alignment pin. Values derived from the magnetic sensors are used to
provide the angle (azimuth) between the DITS pin and magnetic north. Values derivedfrom the gravity sensors (accelerometers) are used to calculate the location of the DITS
pin relative to the high side of the hole (relative bearing) and the deviation of the hole
from vertical. Each set of sensors consists of two sensors mounted at right angles to each
other.
Calculated angles are measured looking downhole from the indicated direction and to the
DITS button in a clockwise direction as shown in Figure 2-8.
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If the tool hangs perfectly vertically, the accelerometer’s output voltage is near zero. The
indicated relative bearing becomes erratic, and the indicated deviation approaches 0°.
The relative bearing stabilizes with approximately 3° of tilt.
Azimuth reading cannot be used in casing because of the magnetic shielding of the tool
from the earth's magnetic field. In open hole, azimuth readings are useful unless the tool
centerline aligns with the earth's magnetic field, causing sensor output voltages toapproach zero.
The deviation and relative bearing are calculated as follows:
and
where
Gx = accelerometer x-axis output voltage.
Gy = accelerometer y-axis output voltage.
Gtot = the output voltage of either Gx or Gy when measuring a 1.0 gravity field. (4.00 V
in the case of the directional sub)
The Quadrant Angle is determined by examining the signs of Gx and Gy.
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Functional Description
System Functions
Automatic Gain Control
Changes in mud attenuation and target reflectance cause the amplitude of the main
transducer signal to vary over a large range. The amplitude of the casing resonance
vibration is less than one tenth the amplitude of the reflected pulse. The differing types
of transducers used in the tool can vary in sensitivity by a factor of over 20: l. Automatic
gain switching is required to cover this large range of signal amplitudes at the
frequencies involved.
To measure the reflected pulse, the tool uses the amplitude of the current transducer
firing to set the gain of its amplifiers for the subsequent shot. Similarly, the tool can alsodetect the maximum amplitude in the resonance window and automatically set the gain
for that part of the waveform. The amplifiers in the tool are capable of changing gains
quickly. In the cased-hole operating mode, the system detects the reflected pulse and
changes the amplifier gain for resonance within the 15-ps period before the start of the
window. Figure 2-9 shows the actual cased-hole waveform as seen at the input to the
digitizer in the tool.
Figure 2-9: Cased-Hole Waveform
Amplifier gains are changed in 3-dB steps, each one multiplying the input signal by a
factor of 1.4. The gain of the system has a range of 32 steps or 96 dB. Waveform
amplitude-related values, such as the peak of the reflected pulse and the sum of the 64
ADC points within the resonance window, are sent uphole with the gain code related to
them.
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Outputs: Scan Data Formats
Tool output data is logically organized into 407 word scans. A scan contains all the data
recorded by the tool for each horizontal sweep in the log images (Table 2-1). Scans are
recorded and stored in the tool at a rate set by the motor speed. They are sent uphole at arate set by the DITS. Untransmitted scans are overwritten. If a new scan is not available
when the telemetry system needs it, the last full scan recorded is sent again. Standard
DITS limits the logging speed in the image mode to approximately 20 ft/min. Processing
time requirements in the tool limit the cased-hole mode logging speed to 30 ft/min.
Table 2-1: Tool Data Scan Format
Word Uplink Data (Cased Hole) Uplink Data (Image Mode)
0 Scan Sequence Number Sequence number
1 Inclinometer X Inclinometer X
2 Inclinometer Y Inclinometer Y
3 Magnetometer X Magnetometer X4 Magnetometer Y Magnetometer Y
5 Slow channel ID Slow channel ID
6 Slow channel data Slow channel data
7 Peak Amp Gain/Peak Amplitude Peak Amp Gain/Peak Amplitude
8 Transit time Transit time
9 Resonant Window Sum Peak Amp Gain/Peak Amplitude
10 Resonant gain / thickness step Transit time
Peak Amp Gain/Peak Amplitude
Transit time
Resonant gain / thickness step
Resonant window sum
403 Peak Amp Gain/PeakAmplitude Peak Amp Gain/Peak Amplitude
404 Transit time Transit time
405 Resonant window sum Peak Amp Gain/Peak Amplitude
406 Resonant Gain / Thickness Step Transit time
0 Scan sequence number Scan sequence number
1 Inclinometer X Inclinometer X
2 Inclinometer Y Inclinometer Y
3 Magnetometer X 3 Magnetometer X
Scans are sent uphole in multiple DITS frames. The single DITS rates are the maximum
108 kbps for the image mode. This rate is also used in the cased-hole combination
service that includes the M305 FWST with the 3-ft and 5-ft receiver tip. A 27-kbps
telemetry rate is used in the cased-hole mode when the tool is run alone. The image
mode sends a scan uphole using 32 word blocks, 9 blocks per 50-ms frame. The cased-
hole mode sends scans uphole in 24 word blocks, 2 blocks per 50-ms frame.
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A test mode is also available that sends a single raw acoustic waveform uphole with each
scan. This mode can be used before logging to observe the output of the transducer and,
if necessary, to adjust the gate opening point.
Slow Channel Data Acquisition
A number of auxiliary data values are sent uphole with the acoustic data (Table 2-2).
This information changes slowly and does not need to be reported to the surface system
as often as the acoustic and directional measurement. Slow channel data is sent uphole at
a rate of one word per scan. An offset value into the slow channel data is also sent.
Table 2-2: Slow Channel Auxiliary Data
Channel Description (Cased-Hole) Description (Image Mode)
1 Casing OD Casing OD (not used)
2 Effective tool radius Effective tool radius (not used)
3 Motor speed Motor speed
4 Motor voltage Motor voltage5 Motor current Motor current
6 Head ID (not used) Head ID (not used)
7 Temperature Temperature
8 Firmware version Firmware version
9 Tool mode Tool mode
10Mud-cell peak gain / Mud-cell peakamplitude (Hi Byte/Lo Byte)
Mud-cell peak gain / Mud-cell peakamplitude (Hi Byte/Lo Byte)
11 Mud-cell transit time Mud-cell transit time
12 Mud-cell sum Mud-cell sum (not used)
13Mud-cell sum gain / Mud-cell thicknessstep (Hi Byte / Lo Byte)
Mud-cell sum gain / Mud-cell thicknessstep (Hi Byte / Lo Byte) (not used)
14 Gate start Gate start
15 Waveform mode flag Waveform mode flag
16 RESERVED RESERVED
Inputs: Tool Commands
The CAST-V system is designed to use a minimum of required inputs from the surface.
All control inputs are set to a default value that usually works for logging. Two inputs
that must always be specified before logging cased-holes are the casing OD and the
effective head radius (the distance from the transducer face to the center axis of the tool).
The surface system reports an error until these values are entered.
Other commands include
• Set Operating Mode - select between cased-hole and image operating modes. This
command is usually sent automatically by the surface software based on the service
selected.
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• Set Gate Opening Point - set the starting point in the waveform for the search for the
reflection peak. This command is sent in the openhole mode when the gate start
position is changed in the CAST-V tool menu.
• Toggle Waveform Display - toggle between normal operation and waveform
monitoring mode. This command is sent in either mode when the waveform
monitoring tool menu item is selected. The surface software disables waveformmonitoring while logging.
Scanner Assembly (Drawing 707.55531)
Description
The scanner assembly (Figure 2-10) contains the primary CAST-V acoustic sensors. A
brushless dc motor turns the main acoustic transducer. The electrical connection to the
main transducer is made through a slip-ring assembly mounted between the head and the
motor. A resolver, mounted above the motor, continuously senses the position of the
transducer face relative to the DITS alignment pin.
A second, fixed transducer is mounted above the motor and resolver with its face
exposed to the borehole fluid. This sensor continuously fires at a 0.3-in. thick plate
mounted 1.25 in. from the transducer. From this distance and the time of flight for each
pressure pulse, the acoustic velocity of the borehole fluid is calculated.
The motor and sensor in the CAST-V scanner operate in a bath of Exxon Turbo Oil 2380
(P/N 0.81792). A piston compensator maintains borehole pressure inside the scanner
assembly. A high-pressure bulkhead connector allows for the required electrical
connections.
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Figure 2-10: CAST-V Scanner
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Block Diagram
The two acoustic transducers in the scanner are of the pulse echo type (Figure 2-11). The
same transducer is used both as a transmitter and a receiver. Firing pulses and the
returning waveforms are connected by two wires from each transducer to the electronicscartridge. The mud-cell transducer is connected directly through the pressure bulkhead
and the 37-pin DITS type connector at the top of the scanner. The rotating main
transducer additionally goes through slip-ring contacts.
The three-phase, brushless dc motor has three wires. Power and ground are connected to
these wires by precisely controlled electronic switches, causing the motor to rotate
clockwise (as viewed downhole). Switch control is provided by circuitry reading the
motor shaft position from the resolver transformer fastened to the top of the motor. The
resolver and associated electronics determine the position of the motor rotor within 0.02°
. Motor speed is proportional to motor voltage, and motor torque is proportional to motor
current. Maximum motor ratings are 150-Vdc at 1.7 A.
Figure 2-11: CAST-V Scanner Block Diagram
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Transducers
• Transducers used in the CAST-V tool are made up of three parts (Figure 2-12):
• • iezoelectric active element that converts pressure changes to and from voltage
changes
• • ound-absorbing backing material to prevent transmission of acoustic pulses intothe tool
• • poxy outer covering that encapsulates the transducer and protects it from
borehole fluids
Figure 2-12: CAST-V Transducer
The piezoelectric ceramic elements used are manufactured as both circular disks and as
rectangles. The thickness of the element determines the frequency of its maximum
output. Backing materials absorb pressure waves launched from the rear of thepiezoelectric element.
The transducers used in cased holes are significantly different from those used in open
holes. They have rectangular elements and an alignment groove that ensures proper
orientation. They are designed to have a wide-frequency bandwidth and short transmitted
pulse. This allows them to be used over as large a range of casing thicknesses as possible
and prevents the reflected waves from interfering with the acoustic waves generated by
the resonating casing. The openhole transducer does not have this requirement and is
designed primarily for maximum output.
CAST-V cased-hole transducers are manufactured with peak output frequencies of 250,
350, and 450 kHz. The type of transducer used is determined by the thickness of casing
to be logged, with thicker casings requiring lower peak frequencies. The openholetransducer has a peak output frequency of 380 kHz. The 450-kHz cased-hole transducer
can be used in boreholes containing high attenuative fluids; however, image resolution is
slightly reduced.
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Directional Sub (Drawing 707.55572)
Description
The four-axis directional sub shown in Figure 2-13 is provided as a smaller, low-costalternative to the full six-axis SDDT. A directional measurement is required to orient
CAST-V images to a fixed point of reference, such as north. Images oriented with the
tool body alone rotate slowly as the tool rotates on the cable.
A two-axis flux-gate magnetometer is used to determine azimuth, the angle as measured
from north to the DITS alignment button. Signals from the magnetometer sensors are
processed by an analog compass board that provides two dc outputs. These outputs are
proportional to the magnitude of the earth’s magnetic field in each of two orthogonal
axes in a plane perpendicular to the center axis of the tool.
A similar function is provided by a two-axis accelerometer package. This self-contained
unit has both the sensors and the electronics required to provide two outputs proportional
to the magnitude of gravity in a plane perpendicular to the tool axis. When the tool isvertical, both sensors are nearly horizontal and read zero. This accelerometer package is
the same as the one used in the Pulse Echo Tool (PET).
Figure 2-13: CAST-V Directional Sub
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Block Diagram
See Figure 2-14.
The analog signals and power for the directional sensors are carried through the compass
board. The directional sub itself contains all the required analog signal-processingelectronics. The main function of the compass board is to convert the 27-kHz signals
from the saturable inductor into voltages proportional to the earth’s magnetic field.
Power for the compass board is provided by power supplies in the electronics cartridge.
Output voltages from the inclinometer are adjusted on the compass board to values
suitable for the slow ADC in the tool electronics.
The directional sub also contains the through wiring necessary to connect the sensors and
motor in the scanner to the electronics cartridge.
Figure 2-14: Directional Sub Block Diagram
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Electronics Cartridge (Drawing 707.55598)
Description
The primary function of the CAST-V electronics cartridge is to record and preprocess the
high-frequency acoustic waveforms from the main and mud-cell transducers. The
relatively high sampling rate required for imaging prevents the transmission of the entire
raw recorded waveform. The required waveform parameters are extracted by the tool, and
these values are sent uphole for further processing and display. The electronics cartridge
also drives the dc scanning motor, handles signals from the resolver, and acquires the
directional data.
Block Diagram
The electronics cartridge block diagram (Figure 2-15) shows the path of acoustic
information as it travels from the transducer to the RTU-B interface. Analog waveformsare amplified, digitized, and then preprocessed by this series of circuit boards. Processed
data are sent to the RTU-B for transmission uphole.
Figure 2-15: Electronics Block Diagram
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The preamplifier/fire board provides the direct interface to the acoustic transducers. Two
transducers can be attached to the board, but only one can be selected at a time. Firing is
done with a 400-V, 1.2-µs pulse timed from the resolver position. The board also has a
receiver preamplifier with gains of -24, 0, and +24 dB. This gain is controlled
automatically by the DSP (Figure 2-16).
Figure 2-18: DSP Block Diagram
The preamplified waveform is then sent to the variable gain amplifier(VGA)/ADC. The
VGA has sixteen 3-dB gain steps that, when combined with the preamplifier gains, give
a total of 32 unique 3-dB system gain values. The automatic gain system provides a
nearly constant level analog signal to the input to the ADC. The ADC operates at a
sampling frequency of 5 MHz and has a range of +/- 2 V. The frequency range of the
CAST-V acquisition system ranges from about 40 kHz to greater than 1 MHz. The ADC
sends a continuous stream of 0.2µs, 8-bit samples to the DSP/gate array board. Logic, at
this point, determines which samples in the stream are recorded and processed.
All CAST-V waveform processing and much of the tool control are done by theDSP/gate array board. The firing cycle is initiated by a start pulse from the resolver-to-
digital (R-to-D) converter board. The DSP then sets the amplifiers in the tool to the
proper gain and sends a fire pulse to the preamplifier/fire board. Logic in the gate array
causes the ADC output values to be recorded in memory buffers. The two buffers
available are each capable of recording for up to 409.6 ps from firing. As the stream of
waveform samples passes through the gate array, they are searched for the reflection
peak. The magnitude and time from firing for this peak are saved in gate array registers.
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In the cased-hole mode, the VGA gain is switched at the proper time in the waveform to
provide the extra gain needed to record the resonance section. The resonance window is
also searched for a peak in real time. This value is used by the DSP for control of the
resonance gain.
After firing the current shot, the DSP begins processing the data from the previous firing.
The first-arrival amplitude is tested to determine the gain needed for the next shot. Incased holes, the peak value in the resonance window is checked to set the next resonance
gain. The peak time values reported by the gate array are used as the starting point for a
search for the true transit time. The DSP searches backwards in the waveform buffer to
find the baseline before the first cycle of the reflection pulse. Transit time is defined as
the end of this baseline, as shown previously in Figure 2-6.
The DSP does further processing on the resonance window in cased holes. The absolute
values of the 64 resonance window samples are summed for the bonding calculation. The
peak frequency component of the waveform section in the window is calculated last. The
majority of the DSP processing time is required by the frequency calculation.
After processing, the DSP sends the results to the V40 telemetry CPU (Figure 2-17) to be
organized into scans. In the openhole mode, the reflection amplitude, reflection gain, and
transit time are sent. The cased-hole mode additionally sends the resonance sum,
resonance gain, and thickness. All DSP processing is done in the time between each
firing of the main acoustic transducer.
Figure 2-17: V40 Telemetry CPU Block Diagram
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The V40 takes the DSP result data from each transducer firing and packages it into scans.
Auxiliary data are recorded and attached to the beginning of each scan. The board has
three scan-sized memory buffers. One is used to build a new scan as it is acquired from
the DSP. Another is used to freeze the scan data as it is sent uphole. The third buffer is
used to synchronize the acquisition process that operates at a rate determined by the
motor speed with the telemetry process, the rate of which is set by the DITS. The V40continuously stores DSP data to the input buffer. When a full scan is acquired, this buffer
is switched with the synchronizing buffer. The telemetry process continuously sends
blocks of data from the output buffer. When it reaches the end of each scan, it checks the
synchronizing buffer to see if a new scan is available. If a new scan has been acquired,
the output buffer is switched with the synchronizing buffer. If not, the output scan is sent
again. A counter in the header of each scan allows the uphole system to detect when this
occurs. Excessive scan duplications indicate that the motor is turning too slowly for the
current logging speed.
Output data from the output buffer are loaded into a first-in, first-out (FIFO) memory
part on the V40 board. The RTU-B takes data from this FIFO serially, one bit at a time.
Synchronizing signals are sent from the RTU to the V40 at the beginning of each
telemetry block.
A limited number of input commands can be sent to the tool to control its mode of
operation. These commands are sent from the RTU-B to the V40. Most commands are
then sent on to the DSP to control waveform processing.
The electronics cartridge also does several required auxiliary tasks. The R-to-D converter
board receives the sine and cosine outputs from the resolver in the scanner and calculates
a number between 0 and 1023 proportional to the angular position of the motor shaft.
This number is decoded on the R-to-D board to create a sync pulse at the zero point and a
start pulse at each firing position. At the zero point, the transducer is aligned with the
DITS connector alignment pin.
The slow ADC board contains a 12-bit resolution ADC used primarily to convert thefour output signals from the directional sub. Additional values measured include the
output of the temperature sensor in the accelerometer package, the motor voltage, and the
motor current. These measurements are sent directly to the V40 CPU through an
asynchronous serial link.
The power supply in the electronics cartridge provides power to all components of the
CAST-V tool, except for the scanning motor. Regulated voltages for various sections
include +5 Vdc and +/-15 Vdc. A 400-Vdc source is provided to fire the acoustic
transducers. DC power for the motor is routed directly to the commutator board from the
cable through the primary windings of the instrument power transformer.
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Circuit DescriptionsThis subsection describes board-level operations of the CAST-V.
Remote Telemetry Unit RTU-B (Drawing 3.85601)
The RTU is the interface circuit in each tool that connects the tool electronics to the
telemetry sub at the top of the stack. The RTU-B has been designed to operate with
either the standard DSTU telemetry sub or the D2TS sub used in the DITS II system at
twice the telemetry rate. For a more detailed discussion of the RTU-B and the telemetry
system, refer to publication 770.00491, D2TS Service Manual.
Each RTU in a DITS toolstring has a unique address. Communication between a tool and
the telemetry sub is in half-duplex. The RTU only transmits on command from the
DSTU/D2TS. When a send data command is received, data words are requested from the
tool acquisition electronics. The data words are formatted according to the MIL-STD-1553 Manchester encoding used on the intertool serial bus and sent out to the telemetry
sub. Other downlink commands are sent to the tool by the telemetry sub and the RTU.
Tool commands (mode codes) can optionally include an additional command data word.
The RTU-B interface printed circuit board consists of
• 1553 bus interface transformer
• 1553 transceiver
• two Actel field-programmable gate arrays (U1 and U3)
• 5.2224-MHz oscillator
• header for JMP1 to JMP4, J4, J5, and J6
• two Positronic connectors (J1 and J2)
• filter circuit consisting of L1, C1, and C2
The Actel gate array U2 contains the 1553 encoder/decoder circuitry which converts
NRZ data from the tool to the 1553 Manchester format of the intertool bus and the
D2TS. Commands from uphole are decoded back to serial NRZ. Data can be taken in
either 8 or 16 bits parallel from header J4, shifted serially to header JMP1, and returned
to gate array U2 for encoding.
Gate array U3 contains the control logic for the RTU-to-tool interface. It validates
commands and data received from the D2TS and sets the proper flags for the tool to
indicate either transmit-receive data commands or transmit-receive mode commands. TheRTU address in each command is compared to that of the tool in the gate array before
any communication.
The 5.2224-MHz oscillator provides the master timing for the board, including setting
either the low- or high-speed ITB bit rates. DITS I tools are set to 217.6 kbps, while
DITS II tools are set to 435.2 kbps. The ITB rate is command selectable if the header
JMP4 is strapped from pin 1 to pin 8. The bit rate select command is XXE9H, in which
XX is the tool address. For example, if the tool’s address is 51H, then the command is
51E9H. The RTU-B always powers up at the 217.6-kbps rate as a default.
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Header JMP1 must be strapped properly for correct operation of the RTU. If the RTU-to-
tool interface is serial and the tool can keep data ready on the serial input, then pin 1 is
strapped on JMP1.
The tool must be able to send data within 27µs after the send data command to use this
option. If the tool cannot respond this fast, then pins 2 and 7 are strapped on JMP1. This
gives approximately 92 ps for the tool to get its data ready. If the tool's interface isparallel, then pins 4 and 5 are jumpered on JMP1.
If the RTU-B is used to replace a single-board serial RTU, the Positronic connectors J1
and J2 are used. If the RTU-B replaces a two-board parallel RTU (data and control), then
headers J4, J5, and J6 are used instead.
Header JMP2 is used to select between 8- and 16-bit parallel operation. Header JMP3 is
set to the RTU-B address of the tool.
V40 CPU Board (Drawing 707.55666)
The V40 CPU board takes processed data from each firing of the acoustic transducerfrom the DSP board and stores it in memory. These data are collected into groups of 100
shots for the cased hole and 200 shots for the image mode. This group of information
corresponds to all the data recorded for each horizontal scan in the images presented on
the log. The following description of the operation of the V40 board is shown in the
block diagram in Figure 2-17.
The V40 CPU board consists of
• 6-MHz NEC V40 microprocessor with internal peripherals
• 32 kbytes of static RAM and 32 kbytes of EPROM
• Actel field-programmable gate array
• FIFO memory to temporarily hold telemetry data
The NEC V40 (U1) is an 8-bit microprocessor similar to the one used in the IBM PC.
The part has built-in peripherals including three 16-bit counter-timers, seven-level
programmable interrupt controller, three-channel DMA controller, and asynchronous
serial I/O port. The processor has 20 address bits that allow access to up to one megabyte
of external memory.
Most of the communication between the CPU and external memory or peripherals occurs
through a three-state address and data bus. To minimize the number of pins on the part,
the data bus and lower eight address lines share the same eight output lines. Latch U6
separates the lower address lines and buffers them. Similarly, bidirectional buffer U7
drives the data lines, and buffers U8 and U9 drive the control output lines and the
remaining address lines. All outputs from the bus taken off the board are buffered.
There are two memory parts on the V40 board. Static RAM U2 is used primarily to
accumulate the data from each shot until all the data for a complete image scan have been
received. EPROM U3 contains the operating program for the microprocessor. This
EPROM is also used for storage of the program for the AT&T DSP32C DSP on the
DSP/acquisition control board. A new program is loaded into the DSP at tool power-up
and when the operating mode is changed at the surface.
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Gate array U4 is used to implement the interface between the V40 and the DITS. Control
and commands from the RTU are transferred through it. In addition, logic is included in
the gate array to decode the processor addresses and create address-select lines for both
the on-board peripherals and the DSP board.
The FIFO (U5) is used to temporarily store the information for a full horizontal scan
while it is sent uphole. The FIFO also provides the conversion between the 8-bit paralleldata of the three-state bus and the serial data required by the RTU-B. When the FIFO
becomes empty, it flags the V40 through the gate array. The V40 then transfers the last
complete scan acquired to it from the DSP. This telemetry-transfer mechanism is the
same in both the cased-hole and image operating modes.
Data are transferred from the DSP board to the V40 using DMA. The rate of data transfer
in the openhole mode is approximately five times that of the image mode and must be
handled by the hardware directly.
In the openhole mode, two data words are transmitted to the V40 with each firing of the
transducer. A new, 200-point horizontal scan line is acquired with each rotation of the
motor. This requires that data be transferred between the DSP and the V40 at a rate of
approximately 24 kbps. An internal DMA controller in microprocessor U1 transfers data
1 byte at a time as it becomes available from the DSP. Memory-enable signals on the bus
are generated by the hardware DSP controller without storing data for a new scan. At that
time, auxiliary information read from the slow ADC board serial line is stored with the
scan. Motor speed is calculated in the V40 by observing the rate at which these sync
pulses occur.
In the image mode, four data words are transmitted with each transducer firing. Scans are
100 points long and require five rotations of the head for acquisition. A new set of four
words is available approximately every 5 ms. The DMA cycle is used only to transfer the
four words from a single firing to a small temporary buffer. The V40 program polls the
DMA controller and, when a new shot is available, transfers the information to the
proper place in the scan buffer.
The two processes of receiving data from the DSP and sending data to the RTU happen
at different speeds. To keep them in sync, the V40 buffers scan data for both. If the
motor is turning at the proper speed, the acquisition process happens faster than the
telemetry process. The latest scan acquired is sent to the telemetry link when it needs
one. If a new scan is acquired before the previous one is sent, the old scan is discarded,
and the new one takes its place. (Each scan has a sequence number to uniquely identify
it.)
The V40 board continues to acquire and transfer scans as long as the motor is turning and
data are being requested by the RTU.
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Commutator Board (Drawing 707.55559)
The commutator board provides the FET switches and driver circuitry to interface the
resolver board to the motor in the scanner of the CAST-V tool.
The commutator board has three sets of FET switches connected to switch voltage from
the auxiliary power connection of the tool to the motor windings. The motor requires that
this power be applied to the motor windings in a controlled manner determined by the
motor’s rotor position. Signals provided by a shaft-mounted resolver working with the
R-to-D board control the FET switches of the Commutator Board.
Refer to the "R-to-D Board (Drawing 707.55561)" for information about the
development of the logic level signals that control the timing of the closures of the FET
switches.
Circuit Description
The motor used in the scanner has three windings connected in a Y configuration. The
wires from the windings are connected through tool wiring to J2-13, J2-14, and J2-15 on
the commutator board. Each motor lead is connected into a pair of FET switches
configured to switch that particular lead to the motor power (V_MOT at J3-1 and J3-2)
or to ground. The top set of switches as shown in schematic 707.55559 (Q3 and Q2) and
the associated drivers are discussed as typical.
FET Q3 can connect the motor lead (MOT_1) to V_MOT. FET Q2 can connect the same
lead to ground. These FET switches are controlled by R-to-D board drive signals
(MOTR_A+ and MOTR_A-) connected to the board through connector J1. Drive voltage
from the resolver board is +15-Vdc when high and ground when low.
To connect MOT_1 lead to V_MOT, FET Q3 must be turned ON. Positive 15-Vdc isapplied to MOT_A+. Note that resistor R1 connects to -15-Vdc. Zener IN4749 drops 24-
Vdc from +15, setting the anode of VR1 and the base of Q1 to -9-Vdc. Resistor R1 is
dropping about 6 V under these conditions. Transistor Q1 draws enough current through
R2 to raise its emitter voltage to about 5.3 V above the -15-Vdc supply lead, pulling in
the process about 1.5 mA through resistor R5. Voltage drop across R5 is about 15-Vdc,
turning ON transistor Q3. The 18-Vdc Zener VR2 is for gate protection. Any voltage
above 7 or 8 across R5 is enough to turn on FET Q3. Drive voltage for Q3 is the same
(or nearly so) for all V_MOT levels from 10- to 200-Vdc.
To turn OFF Q3, the MOT_A+ lead is switched to ground. The -15-Vdc applied to R1 is
not enough to cause 24-Vdc zener to conduct. No voltage is dropped across R1, and Q1
draws no current through R5, leaving Q3 turned OFF. If it is desired to ground the
MOT_1 lead, a +15-Vdc signal is connected to J1-2. This lead is connected directly to
the gate of Q2 through resistor R6, causing the Q2 to turn ON.
Figure 2-18 shows the relationship of the gate-drive waveforms for one pair of switches
and the waveform observed at the collector. The top trace A is of the gate waveform of
the P-FET connected to V_MOT (Q3 in our example). Trace B is of the gate waveform
of the N-FET switching to ground (Q2 in our example). Trace C is of the waveform seen
at the MOT_1 lead. V_MOT is set to 50-Vdc. Note that the gate waveform for the P-FET
(Figure 2-18, trace A) never goes negative simultaneously with positive excursions of the
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N-FET drive waveform (Figure 2-18, trace B). The sloped portion of the drain waveform
occurs when there are no transistors turned ON for that particular motor lead.
The spikes on the drain waveform are the result of the magnetic fields collapsing in the
motor. The peak amplitude of the spike is limited to the supply voltage by the parasitic
body diode of the opposite transistor to the one switched off, that is., the P-FET diode
catches the N-FET turnoff spike. This is normal and desirable because the energy of thespike is captured and returned to the power supply, increasing the overall efficiency. The
repetition rate of the drive waveform is related to the motor speed.
Note that the board is perfectly capable of shorting out the V_MOT input to ground if
both J1-1 and J1-2 are simultaneously connected to +15. The drive circuitry on the
resolver board never does this (Figure 2-18, traces A and B), but in tests, ground all
unused inputs on J1 through a 10-k Ω or lower resistor to prevent simultaneous turn-on.
Inspection of the schematic shows the other two motor leads (MOT_2 and MOT_3) to be
connected to similar circuitry as is connected to MOT_1.
Operational amplifier U1 is connected to sample the current sent to the motor through
Q2, Q5, and Q8. The total motor current is the sum of the currents through R7, R14, and
R21. The voltage across each of these current sense resistors is connected through a4990-Ω resistor into the sum junction U1-2. Voltage at U1-6 (C_SENSE) is coupled to
the slow ADC board in the tool to be measured and sent uphole in the telemetry stream.
The voltage at U1-6 is equal to the current drawn in amperes multiplied by -1 (350 mA
of current show as -350 mV at U1-6).
Figure 2-18: Waveforms from a Commutator Board
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Compass Board (Drawing 707.55574)The compass board contains circuitry to work with a saturable inductor to produce a
magnetometer and some interface circuitry for an inclinometer. Outputs from the compass board
are directed to ADC circuitry in the DITS CAST-V tool. The magnetometer and inclinometerprovide directional information to the logging software.
Power
Power required for the compass board is provided by the CAST-V electronic package directly
above the directional sub. Voltages required are +15-Vdc only. Current drain is approximately 30
mA from the +15-Vdc input and 20 mA from the -15-Vdc lead.
Saturable Inductor
An external magnetic field (dotted lines in Figure 2-19) applied to the saturating core affects the
saturation of the core, making the core saturate easier on the side where the external flux aids
flux from the drive winding. On the opposite side of the core, where the external flux opposes the
flux from the drive winding, the saturation takes longer. When the saturation takes place on one
side of the coil faster than the other, a high-frequency directional burst of flux is generated. This
flux burst is detected by the voltage it induces in the sense coils. The two sense coils are at 90 to
each other (x- and y-axis). The direction of the high-frequency burst can be calculated from the
amplitude of the voltages from the two sense coils.
Figure 2-19: Saturable Reactor Flux Diagram
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The inductor used in the magnetometer circuit has six leads connecting to three coils.
The unmarked terminals on the saturable inductor are the drive windings; the marked
windings are the sense windings. When a square-wave ac drive voltage is connected into
the drive winding through current-limiting source resistance, the current through the
drive winding is similar to that in Figure 2-20, trace C. This waveform was captured by
connecting a storage oscilloscope to TP-1 on the compass board. (The drive waveform is
drawn over the TP-1 signal for reference.) The drive coil supports the entire ac voltage aslong as the core is not saturated, causing little current flow. At the point of saturation, the
drive coil impedance drops drastically, essentially switching the drive signal directly into
R14, resulting in the waveform shown in Figure 2-20, trace C.
Figure 2-20: Analog Waveforms from a Compass Board
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Circuitry
Circuitry to drive the saturable inductor coil and measure voltages induced in the sense
coil windings is located on the compass board. Refer to schematic 707.55574 during the
following discussion.
Oscillator-Driver
Chip U3 provides oscillator-driver functions for the magnetometer. Oscillation frequency
is set by resistor R37 (a factory adjust, or FA) and capacitor C16. Normal drive
frequency to the saturable inductor is between 24 and 30 kHz. Output from the chip at
U3-14 is coupled through resistor R42, capacitor C20, and terminal J2-8 to the saturabie
inductor drive winding. R42 is a fuse in case of a short circuit. Capacitor C20 prevents
any average dc current from flowing in the drive winding.
Sense winding signal outputs are amplified and applied through two analog switches to
integrators to get dc output signals. The analog switches U4/A and U4/D are closed only
for the moment that signals are present from the effects of core saturation. To ensure thatthe closure of U4/A and U4/D encompass the moment of saturation of the saturable
inductor, circuitry has been included to control the saturation point. Feedback circuitry
automatically adjusts the point of saturation to correspond to the closing of switches
U4/A and U4/D. Without this circuitry, the magnetometer would have severe drifts with
temperature.
Control of the saturation curve is accomplished by controlling the amplitude of the drive
signal to the saturable inductor. The closing of switch U4/C is synchronous to the drive
waveform’s positive excursion. Closing of switch U4/B is timed to encompass the
moment of core saturation. Closing U4/B occurs when the switch control voltage goes
negative (Figure 2-21, trace C), selecting the portion of the drive waveform (Figure 2-21,
trace D) containing the moment of saturation of the inductor core. Output of U4/C iscoupled by R16 into the operational amplifier integrator circuitry U1/B and C4. U1/B
amplifies the difference between the integrated output voltage and a dc reference voltage
(set by R4 into R3), which corresponds to the desired average dc signal from the output
of the analog switches. U1/B-7 output is coupled to transistor Q1, which adjusts the peak
amplitude of the drive signal to the proper level to center the moment of saturation in the
time window used by the sense amplifiers over a wide temperature range.
Sense Amplifiers
The two sense windings of the saturable inductor provide an output signal similar to that
shown in Figure 2-20, trace A. The peak height of the pulses shown depends on the
strength of the external magnetic field influencing the saturable inductor. The y-axissignal (from J2-3) is amplified by U2, and the x-axis signal (from J2-1) is amplified by
U5. Both amplifiers are adjusted to provide 21 x amplification of the sense winding
signals before coupling into synchronous switches U4/A and U4/D. Output signals from
U4/A and U4/D are similar to those shown in Figure 2-20, trace B. These switches are
controlled by the output of U6/B (pin 9). Output signal polarity depends on direction (the
negative-going pulse shown might be positive).
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U6/A and U6/B are one-shots. A negative-going pulse corresponding to transition of the
drive signal is available from U3-4 (OSCOUT, Figure 2-21, trace A). This pulse triggers
U6/B, causing it to begin timing to the predicted time of inductor saturation. At this
moment, U6/B triggers (Figure 2-21, trace B) and holds switches U4/A and U4/D closed
for approximately 5 µs, permitting the amplified sense winding outputs (Figure 2-20,
trace A, is gated to yield Figure 2-20, trace B) to enter R/C filters R26/C6 and R15/C5.
The signal is further amplified by U1/D and U1/C before presentation to the ADCthrough J1-1 and J1-2.
Figure 2-21: Gate Timing versus Saturation Curve
The detection and amplification of the signals have been discussed without reference to
the Fas calibrating the magnetometer circuitry. The exact magnitude of output voltage of
the magnetometer is not required to be calibrated to the magnetic field strength passing
through the saturable inductor. The earth’s magnetic field varies from about 0.24 to 0.7gauss. The output voltage from the magnetometer with the approximate values indicated
in the setup procedure is approximately 1.5-Vdc in a 0.45-gauss field. As long as the
peak voltage from the y-axis of the magnetometer is equal to the peak value of the x-
axis, the absolute amplitudes are not important. Only the ratio between the amplitudes is
important.
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Measurement Calculations
If the saturable inductor is rotated around its axis, output from the y-axis circuitry is
shifted from the x-axis output by 90°. As the inductor is rotated (by rotating the
directional sub in a test fixture), the x-axis voltage is at a maximum when the DITSbutton is pointed north. At this time, the y-axis voltage will be at a minimum. With the
DITS button pointed northwest, both voltages are the same. With the DITS button
pointed east, the y-axis voltage is at a maximum, and the x-axis voltage is at a minimum.
The voltages from these detectors may be thought of as sine and cosine waves relating to
the rotation of the inductor. The peak amplitude of the sine and cosine waveforms is
determined by the magnetic field strength. The equation below indicates how the
voltages are used by the tool to indicate direction.
where
A = peak amplitude of MAGX or MAGY
• A*Cos(θ) = MAGX = Signal at J1-25 (upper DITS connector)
• A*Sin(θ) = MAGY = Signal at J1-24 (upper DITS connector)
θ = angle measured from magnetic north
φ = rotator to place the angle in the right quadrant
The operator 4 is obtained by examination of the polarity of the voltages seen at the x-
axis and y-axis output. For the magnetometer circuitry we are discussing, is determined
as follows:
• If MAGX is positive,
• and MAGY is positive, then φ = 0
• and MAGY is negative, then φ = 360
• If MAGX is negative,
• and MAGY is negative, then φ = 180
• and MAGY is positive, then φ = 180
Factory Adjusts
The resistors adjusting the amplifiers are adjusted in a particular sequence. This sequence
is described below;
1. Resistor R37 is used to set the operating frequency to the saturable inductor.
2. Resistor R19 is used to set the positive and negative swings of the x-axis sense
circuitry to the same peak magnitude.
3. Resistor R20 is used to set the positive and negative swings of the y-axis sense
circuitry to the same peak magnitude.
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4. Resistor R18 is usually kept at the same value (10 k Ω). R18 can be changed to adjust
the y-axis peak amplitude to a new value. However, changing R18 requires that the
entire setup be repeated with the new resistor in place.
5. Resistor R1 1 is used to match the peak amplitude of the x-axis output to that of the
y-axis output.
6. Resistor R1 is used to rotate the x-axis signal to get exactly a 90° phase shift fromthe y-axis signal. Always set this resistor equal to R2 during the early stages of the
setup.
7. Potentiometer R8 allows the peak amplitude of the inclinometer y-axis signal to be
set to 4.00-Vdc.
8. Potentiometer R10 allows the peak amplitude of the inclinometer x-axis signal to be
set to 4.00-Vdc.
Data Acquisition Board (Drawing 707.41002)
The data acquisition board for the CAST-V tool consists of an 8-bit flash ADC,amplifiers to optimize the input voltage level to the ADC, and other parts to provide
support. Gain of the amplifiers can be adjusted from 1x to 181x in 1.414x increments
(1.414 = √2 =3.01 dB). Inputs to the board are signal- and digital-control signals.
Outputs from the board are a digital representation of the analog signal, with
measurements on the input signal taken at 200-ns intervals.
Refer to schematic 707.41000 during the following discussion. A circuit description of
the Data Acquisition Board components follows.
Gain Control
Quad-latch U8 is driven by the tool digital electronics to select the gain provided for theADC. Four gain controlled amplifiers (V1, U3, U4, and U6) are cascaded to provide 16
gain steps of 1.414x each. Each gain-controlled amplifier has analog switches connected
to set the amplifier to either unity gain or a greater gain. The 16x stage (U1) with its
controlling analog switch U2 is discussed as typical.
The input signal for U1 is from the preamplifier/fire board through connector J1. The
gain of U1 is controlled by setting the amount of negative feedback provided. To get
unity gain, switch U2/A (pins 1, 2, and 3) connects U1 output (pin 6) to the U1 negative
input (pin 2). To get 16x amplification, switch U2/A is opened, and U2/B is closed,
causing the junction of R3 and R4 to be connected to U1-2. Gain is nearly equal to (R3+
R4) / R4, x15.87. Resistor R38 trims the gain to exactly 16.
Analog switches U2/A and U2/B are controlled by one section of quad-latch U8.
Instructions from the tool processor are connected to pin J2-3 to turn the 16x stage ON or
OFF. This instruction is placed on lead J2-3 by the processor and latched into U8 by a
positive strobe applied to J2-8. If 0 is on J2-3 at the moment of latch U8-2 reaches 0,and
U8-3 reaches 1 (+5-Vdc). The analog switch control voltage requires a 0 to close and a 1
to open. Thus, U2/B is closed; U2/A is opened (note that U8 provides a latched,
noninverted output on pin 2, and a latched inverted output on pin 3). U2/B connects the
R3/R4 junction to the negative input of U1, and the gain reaches 16x.
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Amplifier stages U3, U4, and U6 work in similar manner. Each stage gives either unity
gain or a higher gain set by the resistive divider in the negative feedback path.
In the last stage of amplification, U7 provides a signai inversion and an offset voltage.
The offset voltage is provided to allow the 4-V peak-to-peak bipolar ac signal from the
U1, U3, U4, and U6 amplifier to appear as a 4-V single polarity signal to the ADC.
(When the ac signal is at a -2-V peak, the ADC is presented with a +4-V peak. When theamplifier output is at +2 V, the ADC measures 0 V.) The offset voltage is generated by
dividing the ADC reference voltage (4-Vdc) by 2 and applying the voltage to the positive
input of U7 (pin 3). The divider is formed by resistors R18 and R20. Actual division is
set slightly off one half (R18 is 19.6Ωk instead of 20 k Ω) to keep the ADC MSB from
oscillating too much with zero input signal.
Reference Voltage
Reference voltage for the ADC is provided by U9, reference zener VR1 and associated
circuitry. Zener VR1 provides a 6.4-Vdc temperature-compensated voltage amplified by
U9/A to get a 10-Vdc output at U9-1. The 10-Vdc is divided down to 4-Vdc by resistors
R26 and R34 and buffered by U9/B. The buffered 4-Vdc is applied to the REF input to
the ADC (U10-17) and to divider (R18/R20), which provides the 2-Vdc of offset to the
signal input to the ADC. FA resistor R31 allows the 4-Vdc to be trimmed to exactness. If
the manufacture’s tolerance on the zener is excessive, R24 may have to be adjusted as
well. The zener VR1 is chosen for temperature stability, not initial precision.
ADC
The MP7684 ADC chosen for this tool takes an 8-bit measurement each time the clock
lead goes negative. The clock applied to the MP7684 (U10-1) is 5 MHz, resulting in a
measurement every 200 ns.
Chips U11 and U12 buffer the output of the ADC before presenting it to the other
circuitry in the tool.
Preamplifier/Fire Board (Drawing 707.55668)
The preamplifier/fire board for the CAST-V provides 400-V peak pulses which drive the
mud-cell and scanner transducer. Interface circuitry is also provided to condition the
recovered signals.
The 400-V peak pulse is set to a 1.2-µs pulse width. After the transducer is fired, the
drive circuitry is turned off, and the same transducer is used to receive the reflected
signal. The signal is further conditioned by the data acquisition board before presentationto the ADC. Overall gain of the entire signal path from transducer to ADC is adjusted to
optimize the signal level to the ADC input range. The timing of the firing of the
transducer is controlled by the acquisition control and DSP board.
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Generation Of The Ultrasonic Pulse
Refer to schematic 707.55668. There are two fire circuits on the preamplifier/fire board.
One circuit consists of Q5 and associated circuitry used for the mud-cell, and the other
consists of Q4 and associated circuitry used for the rotating transducer. Q4 andassociated parts are discussed as typical.
U1 EPLD contains gates arranged to take a pulse at U1-2 (TP-2) and gate it to U1-9 or
U1-10. The output at U1-10 is used to fire the rotating transducer, and the output at U1-9
is used to fire the mud-cell transducer. Selection of which transducer to be fired is
controlled by voltage level on U1-3 (TP-1). The U1-3 signal is a positive-going pulse
used to switch the mud-cell to the signal path for enough time to get an entire waveform.
The mud-cell is read only once every 10 scans. Input signals controlling the firing and
selection are received from the DSP and acquisition control board.
Assume that a typical, positive-going, 1.2-µs, 5-V fire pulse is coupled into U1-2. The
pulse is inverted and gated to U1-10. U1-10 is connected into U4, pins 5 and 8. Device
U4 functions as a high-current buffer and level shifter. The output from U4, pins 10 and11, is a negative-going 15-Vdc pulse coupled into the gate of Q4 by parallel connected
capacitors C21, C22, and C23. Q4 turns ON, connecting +400-Vdc and charged
capacitor C34 to the transducer (through connector J2) for the duration of the pulse. After
Q4 turns off, C34 recharges to +400-V through resistor R24, and the charge present in
the transducer (electrically similar to a capacitor) is drained by resistor R40 and the
network R34, R35, R32, R31, and associated parts in HY1's input circuitry. The resulting
pulse shape is shown in Figure 2-22.
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Figure 2-22: Fire-Pulse
Transistor Q5 and associated parts fire the mud-cell. Electrically, they function in a
similar manner to Q4. When the mud-cell is to be fired, the level seen at TP1 (U1-3)
switches to +5 V for the time required to fire the mud-cell and recover the sonic signal.
Positive 5-Vdc on U1-3 causes the fire pulse to exit U1 through pin 9 into U4 pins 1 and
3. Output from U4-12 and U4-13 couples to Q5 through C18, C19, and C20 and fires the
mud-cell transducer connected to J1.
Recovering the Return Signal
The rotating transducer signals are coupled to the amplifiers and signal-conditioningcircuits through input resistors R34, R35, R31, and R32 from the transducer connection
at J2. The hybrid HY1 can be set up to provide a loss of 0.0635x (-24 dB), unity gain, or
a gain of 15.86x (+24 dB). The hybrid also contains the gating circuitry that switches the
return sonic signal to the measuring circuitry.
Gating of the sonic signal is controlled by an input to U1-6. This signal goes negative
while the fire pulse is generated, and while the ring-down effects from the fire pulse are
present. The signal can be adjusted in length by the software for the tool, but typically a
20-µs, negative-going pulse with the leading edge synchronized to the fire pulse is
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observed at U1-6. The inverted gate pulse exits U1 on pin 20, enters HY1 on pin 27, and
controls an analog switch in the signal path.
Control signals from the tool processor set the various gains according to Table 2-3.:
Table 2-3: Input Select and First-Stage Gain Control
HY1-31 HY1-32 Result
0 0 0-dB gain, mud-cell unity gain
0 1 -24-dB gain, mud-cell 0.06345x
1 0 0-dB gain, rotating transducer unit gain
1 1 -24-dB gain, rotating transducer 0.06345x
A second-stage amppifier in the hybrid (in the lower right of the hybrid in schematic
707.55668) provides unity gain or +24-dB gain according to the Table 2-4.
Table 2-4: Second-Stage Gain Control
HY1-28 Result
1 0 dB unity gain
0 +24 dB 15.86x
Assume that the tool processor has setup the preamplifier/fire board to provide high gain
(+24 dB) on the rotating transducer. To get +24 dB, the first-stage gain is set at unity,
and the second-stage amplifier gain is set to 15.86x (+24 dB). Digitally, the setup is as
follows:
1. HY1-28 is set to 0.
2. HY1-31 is set to 1.
3. HY1-32 is set to 0.
The two- to four-decoder in HY1 with the above input levels connects the signal path
from the unity gain amplifier (third amplifier on the left in the HY1 schematic
707.55668) to HY1-36. The signal from HY1-36 is coupled back into the hybrid to the
second-stage amplifier through HY1-25.
The second amplifier stage in the hybrid (circuitry at the lower right of the hybrid in
schematic 707.55668) is programmed by setting HY1-28 to 0-Vdc. Gain provided with
HY1-28 at 0 V is +24 dB (15.86x). The output signal from HY1-21 is routed to Q3 by
board wiring.
Q3 is an active glitch suppressor to help remove undesirable switch glitches from the
signal. From Q3, the signal passes through a high-pass filter consisting of U5 and
associated parts to a low-pass filter consisting of U3 and associated parts to connector J3,
the output signal connector of the board. Response characteristics of the board, including
and primarily dependent on the filter characteristics, are shown in Figure 2-23.
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Figure 2-23: Gain and Frequency Response Curves
If the hybrid is programmed to provide unity gain, the amplifier in the lower left of the
hybrid is programmed to 1x gain. All other parts of the signal path are the same as the
previously discussed +24-dB setup. Digital setup is as follows:
• HY1-28 is set to 1 (sets second-stage gain to unity).
• HY1-31 is set to 1 (with HY1-32, sets input gain to unity).
• HY1-32 is set to 0 (with HY1-31, sets input gain to unity).
To apply a gain of -24 dB (0.06345x) to the rotating transducer signal, the second-stage
amplifier is programmed to 1x; the input amplifier is switched from the amplifier with
the 5-k Ω feedback resistor to the amplifier with the 500-Q feedback resistor. Digital
setup is as follows:
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• HY1-28 is set to 1 (sets second-stage gain to unity).
• HY1-31 is set to 1 (with HY1-32, sets input gain to -24 dB).
• HY1-32 is set to I (with HY1-32, sets input gain to -24 dB).
For a -24-dB gain, the signai from J2 enters the hybrid through R32 and R31 into HY1-
10. The gain of the first-stage is R32 (3400 Ω) plus R31 (3480 Ω) plus 1000 Ω (inside
hybrid) divided into 500 Ω (the feedback resistor inside hybrid). The gain would be
0.06345, or -24 dB. Note that the unity gain input amplifier and the -24-dB input
amplifier are both always connected to the transducer.
Auxiliary Circuitry
Transistors Q1 and Q2 and dual amplifier U2 are connected as regulators to provide +7-
Vdc to power HY1. Reference voltage for the regulators is provided by zener VR1. U2/A
is adjusted to amplify the zener voltage to +7-Vdc by setting the size of FA resistor R7.
Q1 is mounted to a heat sink to help absorb the power dissipated during regulation.
U2/B is connected as an inverting amplifier, causing Q2 to turn on until the current
through R5 matches the current through R6. FA resistor R6 is set to cause this current
match when the output of Q2 is at -7-Vdc. Q2 is mounted to a heat sink to absorb the
dissipated power.
CAST-V Power Circuitry
This section discusses the powering of the CAST-V tool (assembly 707.50606 and
associated chassis mounted components), including operation of the following circuits:
• power interface to the tool bus
• inverter and control circuit for local +5-, +15-, -15-, and 400-Vdc power supplies
• motor voltage
Circuit Description
Power enters the tool through pins 13, 14, 16, and 19 (refer to the block diagram in
Figure 2-24). These pins correspond to cable conductors as shown in Table 2-5.
Table 2-5: CAST-V Power Conductor-to-Pin Identification
Conductor Pin Color
1 13 BRN
2 14 ORG
4 16 YEL
5 19 BLU
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60-Hz 120-Vac power for the instrument section is fed into large chassis-mounted
transformer T1, with 120-Vac applied across the BRN and ORG leads and across the
YEL and BLU leads. The 60-Hz power is phased and balanced so that the two center taps
(RED and GRN) on T1 do not show voltage when ac power is applied. Application of ac
power in this manner is W5 mode. The surface system can also feed dc voltage down the
center taps of conductors 1 and 2 versus conductors 4 and 5. Application of power in this
manner is W2 mode. Power applied in W2 mode is used to operate the scanner motor of the CAST-V. The operation of the instrument power circuitry running from the W5 mode
is discussed first, followed by a discussion of the operation of the W2 mode motor
power.
Instrument Power
Instrument power is obtained from the W5 mode power supplied by the wireline. A
chassis-mounted transformer and two printed circuit boards (707.50603, preregulator,
and 707.50600, inverter) convert the W5 power into voltages appropriate for tool
operation.
60-Hz power at approximately 120-Vrms is applied to windings W1, W2, W3, and W4.
The voltage is coupled by the transformer to W5 (141-Vrms nominal) and to W6 (27.6-
Vrms nominal). Windings W6 and W5 are connected series opposing to get an output
voltage of (141 - 28) or 113-Vrms which is rectified and fed to the DC-DC inverter,
which develops the tool operating voltages. T1 winding W7 provides the 27 V used for
starting the inverter.
The normal DITS operating range for instrument power is 120 V +/-15%, which means
from 102 to 138 V. Output from T1 ranges from 86 to 117-Vrms at the input of the
bridge rectifier.
The 86- to 117-Vac from the transformers is rectified by a CR1-CR4 on the preregulator
board and filtered by inductor chassis-mounted L1 and C2 before passing through
transistor Q1 to the inverter. Transistor Q1 is controlled by an error amplifier sensing the
+5 V output. The 5-Vdc output is the only low-voltage source on the tool in a tightly
controlled regulator circuit. The +15- and -15-V output of the inverter are much more
likely to drift with temperature and load. The 400-Vdc that fires the transducer is also
tightly regulated.
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Figure 2-24: CAST_V Power Circuitry Block Diagram
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As power is applied to the chassis-mounted T1 several things happen:
1. When voltage in winding W7 gets high enough, the inverter starts.
2. The inverter, drawing power from pass transistor Q1 begins generating voltages at
the various outputs.
3. Regulator circuitry senses the increasing voltage from the 5-Vdc inverter output andbegins regulating the inverter input voltage through Ql to hold the 5-Vdc output
steady.
4. A step-up transformer, running from ac coupled from the main inverter circuitry,
generates 460-Vac which is rectified, filtered, and regulated to 400-Vdc for firing the
transducer.
Startup
Refer to schematic 707.50600. AC voltage from winding W7 connects to J1-1 and J1-9.
Rectified output from W7 passing through R5 and R4 turns on transistor Q1. Q1 emitter
increases voltage until the turn-on voltage (10 V) of zener CR3 is reached. Voltage is fedthrough CR5 to provide 9 V on the power leads of U1. U1 begins oscillating, feeding
square-wave drive voltage into the gates of Q2 and Q3. The startup circuit disconnects
whenever the voltage at the cathode of CR6 becomes higher than the 9 V supplied by the
startup circuitry. After startup, the power to operate U1 comes through CR6, and CR5 is
reverse biased.
Inverter
The inverter consists of Ul, Q2, Q3, T1, and associated parts. Chip U1 is a general-
purpose oscillator/FET driver designed for use in switching regulators. U1 is used to
provide square-wave drive voltage at high-current for transistors Q2 and Q3. Oscillation
frequency is set by R7 and C3. R6 provides a dead time (neither Q2 or Q3 conducting) tomake the turn-on and turnoff times of FETs Q2 and Q3 less critical. Resistors R14 and
R15 prevent parasitic oscillations by FETs Q2 and Q3.
Q2 and Q3 begin switching power through transformer T1, generating ac voltage at the
output windings of board-mounted T1. The voltages are rectified and coupled to filter
networks consisting of L1, L2, L3, and their associated capacitors. These networks
remove inverter noise from the output voltages.
The TSC15C25 device used for U1 is designed for use in a wide variety of switching
regulator circuits, and much of the internal circuitry is not used. Some of the circuitry is
used as a current limiter, however, to limit the supply dissipation if a short occurs on one
of the output voltages. The operation of this limiting circuitry is discussed next.
Current drawn by the inverter is sensed by a 0.5-Q resistor (R16) between the source lead
of FETs Q2 and Q3 and ground. As current is drawn by the tool, the voltage at the
junction of R16/R11 increases at 2 V/A. This voltage modifies the voltage at the
negative input (U1-1) of an internal operational amplifier in U1. If the voltage at the
negative input passes a fixed reference voltage (1.25-Vdc) at the positive input (U1-2),
the supply begins current limiting by causing the ON times of Q2 and Q3 to drop. This
current limiting occurs at about 400 mA of tool current. Normal voltage across R16 is
about 90 mV.
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Note Experience with this circuit has shown that prolonged short circuits on the low-
voltage outputs cause failure in the input filter capacitors for the shorted output.
The operating current for the current limiter voltage reference (Zener CR2) is supplied by
diode CR1 and resistor R1. CR1 is a 1-mA current diode; it provides 1-mA of operating
current for CR2 over a wide range of input voltage variation.
Diodes CR7 and CR8 catch the spikes generated by the power transformer at the moment
the FETs are switched. Energy in the spike is fed back into the power input to the supply
through R17.
Preregulator
The preregulator board contains the control circuitry for the inverter, the rectifiers for the
60-Hz input power, and the circuitry to develop the 400-Vdc used to fire the transducer.
Diodes CR1 through CR4 (refer to schematic 707.50603 and to Figure 2-24, block
diagram) are used to rectify the output voltage from chassis mounted T1. The rectified
and filtered voltage is connected to the Q1 chassis-mounted drain. This transistor is
turned on by current flowing through R1 and R3 into the gate. The output of the FET
(“82 V Regulated” on schematic 707.50603) is coupled to the inverter for conversion to
lower voltages as required for the tool electronics. Off-board mounted CR17 is a 91-V
device used to prevent excessive overvoltage to the tool electronics if the preregulator
fails.
Control of pass transistor Q1 is accomplished by comparing the +5-Vdc output of the
supply to a zener-stabilized voltage and adjusting the conduction of Q1 to provide just
enough power for 5 V output.
Reference zener CR11, a 6.4-Vdc device, provides a low-drift 6.4-Vdc source. The
voltage from this zener is amplified to get a 10-V output. R34 is used as an FA to set the
output of U1 to exactly 10-Vdc. This 10-Vdc is the reference for all the output voltages
of the supply.
10-Vdc is fed into the input of U1/A through a voltage divider consisting of R12, R13,
and R10 into R11. After adjustment of R13, the final voltage at the R10-R11 junction
(the positive input of U1/A) is +5-Vdc. Negative input U1/A is connected to the +5-Vdc
output of the supply through R9. When the reference voltage is larger in magnitude than
the sensed output voltage at R9, the operational amplifier output goes positive, turning
Q2 OFF. As Q2 is turned OFF, Q1 is turned ON by resistors R1 and R3, raising the
input voltage to the inverter and all output voltages from the inverter. When the
5-Vdc output of the inverter matches the 5-Vdc reference voltage, the operational
amplifier adjusts the conduction of Q1 through Q2 to exactly hold that level of
conduction to maintain the 5-Vdc out. Components R8, C5, C4, R6, and C3 are used toprevent the amplifier from oscillating.
400-Vdc Circuitry
When the inverter and preregulator are functioning correctly, the ac voltage swing at all
points on the inverter transformer is predictable. An ac signal is taken from the secondary
of the main power transformer and connected to step-up transformer T1 (not the 60-Hz
T1 but rather a small transformer shown on the preregulator schematic). T1 provides a
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large step up in voltage. The output of T1 (near 465-Vac) is rectified by CR13-16,
filtered by L1 and the components shown clustered around L1, and applied through
resistor R32 to a shunt regulator circuit consisting of Q3, Q4, U1, and associated parts.
Resistors R21 and R20 cut down the dissipation required in Q3. Q3 gate is grounded and
control of the FET is accomplished by lowering the drain of Q3 by Q4 enough below
ground to cause Q3’s grounded gate to turn on the FET. Control of Q4 gate isaccomplished by a section of quad amplifier U1. The 10-Vdc reference voltage is
connected to the positive input (pin 12) of the operational amplifier. The 400-Vdc output
is connected to a voltage divider set to give 10 volts at the negative input (pin 13) of the
amplifier. If the output voltage gets too high, the output of the amplifier goes negative,
turning on Q4, which turns on Q3, which loads down the output voltage until the divider
provides exactly 10-Vdc at pin 13.
Motor Voltage
Refer to Figure 2-24, the block diagram. The RED and GRN wires from the center taps
of the instrument power transformer are the source of motor power in the tool. Two large
chassis-mounted 150-pF capacitors, C1 and C4, are connected across motor power to act
as reservoirs to handle the surge currents of the motor commutation circuits. The GRN
wire, corresponding to the center tap of J1-16 and J1-19, is connected to ground in the
tool and is the negative power input lead. (Note that this connects armor in parallel with
lines 4 and 5 for W2 power.) The RED wire, connected to C1+ and C4+, is the positive
power input lead corresponding to the center tap of J1-13 and J1-14. Motor voltage and
current are monitored by circuitry in the commutator and slow ADC boards.
R-to-D Board (Drawing 707.55561)
The R-to-D board contains circuitry to control commutation for the scanner motor of the
CAST-V tool. Commutation is the act of switching current through field windings tocause the rotor of the motor to rotate efficiently. The actual switching of the drive
voltage to the motor is accomplished by the commutator board (707.55559). The R-to-D
hoard provides control signals to the commutator board. The R-to-D board also provides
circuitry to set the pattern of the sonic pulses as the head rotates.
Circuit Description
Refer to schematic 707.55561 during the following discussion. It is necessary to know
the position of the rotor of the motor to select the correct way to of energize the motor
windings to get rotation. The position of the rotor is sensed by a resolver fastened to the
shaft coming out of the motor. There are three windings on the resolver, a rotating drivewinding and two signal-output windings. The resolver drive signal REFA can be seen at
J2-4. REFA is obtained from a sine wave oscillator on the R-to-D board. The resolver is
wound to provide a sine- and cosine-output signal which is a function of the shaft
rotation. The two output signals from the transformer are connected to J2-7 and J2-5 of
the R-to-D board.
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The signal to drive the resolver is provided by a sine wave oscillator made with U8, U7,
Q1, Q2, and associated parts. A 5000-Hz (approximate, any frequency in the 4500- to 6-
kHz range) sine wave appears at the emitters of Q1 and Q2. Oscillation results from
positive feedback from Q1/Q2 emitters through R3 into low-pass active filter U8. U7 is
also connected as a low-pass filter. The amplitude of the oscillation is maintained by the
clipping of CR1 and CR2. Frequency of oscillation is determined by the phase shift and
amplitude characteristics of the low-pass filter elements. The distortion created by theclipping of the diodes is removed by the low-pass filtering of U8 and U7. An oscillator
of this type is sensitive to component values. Take care in selecting components for
repair.
The resolver transformer drive waveform (REFA) is shown in Figure 2-25.
Figure 2-25: Waveforms from the Oscillator and Resolver Transformer
On Figure 2-25, the COS waveform was taken at the same time as the drive waveform.The sine waveform is very similar to the COS. At any given moment, the COS
waveform is almost in phase or almost out of phase with REFA.
The amplitude of the COS waveform varies as the motor rotates, as is shown in Figure 2-
26.
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Figure 2-28: Amplitude Modulation Resulting from Rotation of the Scanner
At the points where the COS waveform seems to go to zero, the phase of the 5000 Hzinverts. The sine input (U1-7) is at zero at the time the transducer face points at the DITS
button. At that moment, the COS input to U1 goes to maximum amplitude. Slightly
clockwise of DITS, the sine waveform is in phase with REFA. Slightly counter-
clockwise of DITS the sine waveform is out of phase with REFA.
The 5000-Hz sine wave is connected to the drive winding on the resolver through J2-4.
The 5000-Hz signal is also connected to the REF input of U1 for phase reference in
determining the orientation of the resolver.
The inner workings of U1 (AD2SSO) are not discussed here, its purpose is to convert the
sine and cosine analog signals into a digital number proportional to the current rotor
shaft position. The resistor-capacitor networks connected to U1-2 an U1-3 connect an ac
error signal (U1-3) into an internal phase-locked loop. The resistor-capacitor networks onU1-37, U1-39, U1-38, and Ul-40 shape the response curve of error amplifiers within the
device. Pins with signals of interest are the BUSY (U1-33) and RCLK (U 1-35). RCLK
provides a pulse whenever the BIT outputs are all 0, which happens only once per
revolution. BUSY (Ul-33) is low when the data lines (BITO - BIT15) are valid.
Data lines B15 through B6 are connected to the address lines of EPROM U2. U2 is
programmed to provide drive signals to operate the FET switches on the commutator
board. These signals appear on U2 output leads Q1 through Q6. As the digital output
from U1 changes to reflect the position of the rotor of the motor, programming in U2
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selects the appropriate commutator board FET switches to operate. As the rotation takes
place, the START lead (Q8, U2-19) is programmed to provide a pulse whenever the rotor
is at the appropriate place for a sonic pulse. Three of U2’s address lines (RATE0 at U2-
21, RATE1 at U2-23, and RATE2 at U2-2) are connected to the tool’s microprocessor
through U11, J1-6,
J1-13, and J1-12. The RATE lines allow the microprocessor to change the pattern of thesonic pulses. Another output provides a pulse (TACH/REF) once per revolution for
synchronizing purposes.
U3 is a latched buffer controlled by U4-14 that ensures that output signals are not
enabled during the moments when the EPROM output is changing. The latch signal from
U4-14 corresponds to U1-33, the BUSY signal from the AD2SSO chip. An input into U4
from the microprocessor provides an additional latch signal to ensure that the motor has a
valid pattern at startup.
U9 and U10 are level shifters to raise the digital signal levels to 15-Vdc which is more
appropriate to the commutator board input circuitry. Enable lines U9-2 and U10-2 are
controlled by a flip-flop in U4 that is SET or RESET by a pulse on SEL0, qualified by
the state of IOWR or IORD. Whenever IOWR and SEL0 are simultaneously LOW, theMOTSW lead of U4 goes high, turning the motor ON. When IORD and SEL0 are
simultaneously LOW, the motor turns OFF.
Integrated circuits U5 and U6 provide a serial output (POS DAT at J1-10) reflecting the
position of the resolver. Readings of U6 and U5 are controlled by the tool
microprocessor. Loading of U5 and U6 is done by the buffered BUSY output of the
AD2S80. Currently, the output of U5 and U6 is not used.
Slow ADC Board (707.55587)
The slow ADC Board is designed to function as an eight-input voltmeter. The slow ADC
is presently connected to measure the following signals:
• motor voltage
• motor current
• magnetometer x-axis
• magnetometer y-axis
• inclinometer x-axis
• inclinometer y-axis
• inclinometer temperature
• Head ID is not currently used
The slow ADC board sends one voltmeter reading to the microprocessor each time it is
strobed by the processor. Data are sent to the serial port of the V40 microprocessor as 2
bytes of data, where 3 bits are a tag for the location of the reading and 13 bits are the
reading from the ADC (12 bits of magnitude and 1 as a sign). Each transmitted reading is
actually the last done by the ADC. If the ADC is strobed when the input selector is set to
read the Magnetometer x-axis, you get the motor current reading. The Magnetometer x-
axis reading comes from the next strobe.
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2-48 Theory of Operation 770.00696 - NW 07/97
Circuit Description
A circuit description of the slow ADC board components follows.
Analog Circuitry
Analog circuitry consists of the following parts:
• reference circuitry for ADC
• regulator to provide -5-Vdc to the ADC
• analog switch to select the measurement
• buffer amplifier
Refer to schematic 707.55587 during the following discussion.
Reference Voltage
Reference voltage (4.5-Vdc) for the ADC U4 is provided by LT1019-4.5 (U3). Outputfrom U3 is coupled to the ADC through capacitor bypass circuitry C16, C17, and R7.
LT1019 output drift directly affects the reading of the ADC. If the LT1019 drifts down in
voltage, the reading of the ADC drifts up by the same percentage. Typical drift of the
LT1019 is about 0.3% at 175°C.
Negative 5-Vdc
The CS5014 requires -5-Vdc at about 14 mA as one of its supply voltages. Because this
voltage is not a normal output of the CAST-V tool power supply, it was provided to the
CS5014 by a local regulator from the -15-Vdc provided by the CAST-V tool power
supply. Negative 15-Vdc enters the regulator through R8, where some of the waste
power is absorbed. Transistor Q1 is controlled by U2/B. U2/B’s positive input (pin 5) isgrounded; all control is through the negative input at pin 6. Approximately 99.3 µA of
current is fed from the+4.5-Vdc regulator through R6 into U2-6, causing the U2-7 output
to go negative, bringing the base of Q1 negative until the Q1 emitter pulls enough
current through R9 to exactly counterbalance the current through R6. The operational
amplifier adjusts its output voltage to maintain the negative input at exactly the same
voltage as the positive input. When the amplifier is working correctly, U2-5 and U2-6 are
at the same voltage. This condition occurs when emitter Q1 is at -5-Vdc.
Input Selector
Analog switch U1 is connected to multiplex eight inputs to one output. The various input
voltages to be measured are divided by resistor networks (R1 into R2 is typical) to get avoltage in the 0- to 5.0-volt range. Each input resistor network is coupled to a 1-µF
capacitor, which provides stability to the voltage reading at the moment the measurement
circuit is connected. If the measurement is of a voltage of absolute magnitude below
5.0-Vdc, the input network does not have a divider resistor to ground. The voltage
selected by the switch appears at U1-8 to be coupled to buffer input U2-3. Selection of
which input to measure is controlled by EPLD counter circuitry (U11/B) coupled to U1
address lines ADR0, ADR1, and ADR2.
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07/97 770.00696 - NW Theory of Operation 2-49
Buffer
Amplifier U2-A is wired as a unity gain buffer. Resistor-capacitor network R4/C15 does
not affect the gain but does provide some input bias current compensation for U2-A.
Output from U2-1 is coupled through R10 into R11 and the ADC. The voltage divider
action of the two resistors raises the 4.5-V measurement range of the ADC to 5 V.
Diodes CR1 and CR2 prevent the ADC from receiving a voltage significantly higherthan the ADC operating voltages.
Digital Circuitry
The slow ADC board is designed to transmit a measurement to the CAST-V
microprocessor board whenever strobed by the processor. When this strobe occurs,
several things happen:
1. The previous measurement value and location is latched into a shift register.
2. The ADC switches from self-calibration mode to measure mode.
3. The ADC latches a new analog value to be measured.4. The new analog value is measured by the ADC.
5. The previous measurement is clocked out to the microprocessor at 9760 baud.
6. The ADC is put into self-calibration mode, in which it remains until the next strobe.
Since everything happens as a result of a strobe, processing of the strobe is discussed
first.
Strobe
A negative-going strobe is applied to J1-13 (SPARE0). The strobe is qualified by the
IOWR signal from the microprocessor at J1-16. Qualification is accomplished by U11/S,U11/U, and U11/F in the EPLD U11. The strobe applied through J1-13 originates at the
microprocessor board. Qualification means that the strobe line must go negative at the
same time as the IOWR line before the ADC begins a measurement. The qualified strobe
connects to U5-1, U6-1, and U7-1, and the three shift registers that clock out the 2 bytes
of data to the microprocessor. The strobe causes the shift registers to latch the last
measurement held at the output of the ADC. The strobe also clears several flip-flops in
the EPLD U11 and preloads U8 in preparation for the transmission of the measurement
to the processor.
Counters
Preloading U8 sets the CO/ZD output of U8 to 1, allowing counter U10 to begincounting. The RCO output of U10 is used to enable U11/D. The clock for U11-D is the
same as U10, and U11/D may be regarded as an extension of U10, making a 5-bit
counter out of a 4-bit counter. Output from U11/D times the shift rate of U5, U6, and U7.
Each shift clock is counted by U8. When 24 shift clocks occur, U8-14 goes low, which
stops the counting of U10 until the next strobe from the tool processor. The shift clocks
coupled to the shift register occur at 9760 Hz.
Counter U11-B in the EPLD counts once for each measurement cycle. Its outputs are
directed to the address lines of U1 to select the channel to be measured. The counter
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2-50 Theory of Operation 770.00696 - NW 07/97
outputs feed shift register U5-4, U5-3, and U5-14 simultaneously. Thus, the strobe pulse
that loads the shift registers with the ADC reading also loads a tag about where the
measurement was made. The first three data bits shifted out of the shift register are the
location of the reading.
EPLDThe remainder of the parts in U11 not already discussed are used to provide timing
margins for the signals used on the assembly. Flip-flop U11/R only allows U11/L and
U11/M to function after a delay time set by the connection to counter output U9-12. Flip-
flop U11-L and U11/M provides a signai to latch the next analog voltage into the ADC
after it has recovered from the transition from calibration to measurement (Figure 2-27).
Some parts (U11/Y, U11/X, U11/2, and U11/AA) are used to gate a monitor program
and ADC into the V40 board. Gating is controlled by U8-14. (The monitor program is
only used in the design phase of the tool and is not available to the field.) The ADC has
uncontested access to the V40 board whenever a measurement is transmitted.
Figure 2-27: Timing Relationships of STROBE, CAL, and HOLDNOT
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Internal Calibration
The CS5014 ADC has an internal calibration routine built into the chip. This calibration
routine begins whenever the CAL input (U4-35) is high. On this board, the ADC is idle
for most of the time between strobes from the microprocessor. The CO/ZD output of U8
is low during this idle time. The CO/ZD output from U8-14 is inverted by U11/H andconnected to the CAL input of the ADC, thus causing the chip to self-calibrate during the
time between measurements.
RS-232 Data Output
Data Output
The RS-232 format requires that data be produced with a plus and minus voltage swing.
The data stream produced by this board has the same arrangement of ones and zeros but
uses a 0- to 5-volt, logic level signal format instead of the bipolar RS-232 format.
The slow ADC card uses three shift registers, US, U6, and U7, to generate the pseudo-
RS-232 signai. The three chips are daisy-chained together by connections from U7-9 to
U6-10 and from U6-9 to U5-10. The U5-9 output is connected to U11-20. EPLD parts
U11-Y, U11-X, U11-Z, and U11-AA are connected to gate the slow ADC into the V40
processor after a measurement has been made and to allow a monitor program to
communicate with the V40 when the ADC is idle. Final output to the V40
microprocessor is from U11-16.
By examination of inputs to the shift registers, the sequence of the bits transmitted can be
seen and are shown in Table 2-6.
Table 2-8: Sequence of Bits Transmitted
Bit No. Device Pin Bit Function
1 U5-6 STOP BIT always high
2 U5-5 START BIT always low
3 U5-4 ADR0 LSB measurement address
4 U5-3 ADR1
5 U5-14 ADR2 MSB measurement address
6 U5-13 DB3 LSB measurement address
7 U5-12 DB4
8 U5-11 DB5
9 U6-6 DB6
10 U6-5 DB7
11 U6-4 STOP BIT always high
12 U6-3 STOP BIT always high
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2-52 Theory of Operation 770.00696 - NW 07/97
Table 2-6: Sequence of Bits Transmitted (concluded)
Bit No. Device Pin Bit Function
13 U6-14 STOP BIT always high
14 U6-13 STOP BIT always high
15 U6-12 START BIT always low
16 U6-11 DB8
17 U7-6 DB9
18 U7-5 DB10
19 U7-4 DB11
20 U7-3 DB12
21 U7-14 DB13
22 U7-13 DB14
23 U7-12 DB15 MSB measurement value
24 U7-11 STOP always high
Note The CRYSTAL CS5014 pin labeled "DB15" is actually the 13th bit of data
transmitted (DB0 through DB2 are missing in the table above).
Output Waveform
Figure 2-28 shows the transmitted waveform from the slow ADC board when all inputs
are at 0. As indicated in the previous table, the first bit transmitted is a STOP bit, or the
first output is a high. The next shift gives a low, or start bit. The third shift gives theLSB of the address until the end of the first byte. Then four stop bits are transmitted, a
start bit, the rest of the data, then a stop bit, and then the output is tristated, as indicated
by the decay curve after the last stop bit. Observation of the waveforms produced by a
working slow ADC Board shows the ADDRESS and DATA bits to be changing
continuously.
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Figure 2-28: Timing Relationships of STROBE, CAL, end RS-232 Output
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Halliburton Energy Services
07/97 770.00696-NW Disassembly and Assembly 3-1
Disassembly and Assembly
IntroductionThis section provides detailed instructions for basic DITS tool and CAST-V scanner
assembly and disassembly.
Tools And Equipment Required• Spanner wrench - P/N 3.42484
• Chassis insertion and removal tool - P/N 3.30014
• DITS contact insertion and removal tool - P/N 3.29991
• Vise
• Miscellaneous handtools
• 18-in. crescent wrench or channel lock pliers
• Soldering iron and H.M.P. solder• RTV sealant - P/N .21102
• Loctite #620 - P/N .80953
• Loctite #242 - P/N .81785
• Loctite #290 - P/N .81784
• Loctite Primer "T" - P/N 789.00265
• Exxon Turbo Oil 2380 - P/N .81792
• Vacuum pump and accessories - (see 770.00013, Evacuation Procedure)
• Oil-fill gage - P/N 707.55673 (supplied with scanner)
• Oil-fill tube - P/N 707.55581 (3 are supplied with scanner)
• Hand pressure pump (Enerpac or equivalent) - P/N .88774
• Threaded ring tool - P/N 707.55578 (supplied with scanner)• Shrink tubing - clear - P/N .83755
• Oil treatment - P/N .22933
• Bearing tool - P/N 707.55615 (supplied with scanner)
• Seal sizing cylinder - P/N 707.55624 (supplied with scanner)
• Wire markers from kit - P/N .60009
Section
3
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3-2 Disassembly and Assembly 770.00696-NW 07/97
Basic DITS Disassembly
Electronics and Directional Sub
Use the appropriate engineering drawings for reference when disassembling the tool
section assembly.
1. Place the tool section assembly on a clean, stable work surface.
2. Remove the female thread protector from the top of the tool section assembly.
3. Adjust the T-handle on the insertion and removal tool to retract its three tabs into the
cylinder. See detail A of Figure 3-1.
4. Insert the insertion and removal tool into the bottom of the tool housing, fitting the
wide slot of the insertion and removal tool over the wide tab of the connector. See
detail B of Figure 3-1.
5. Carefully match the alignment slot on the collar of the insertion and removal toolwith the alignment slot on the housing.
6. Pull back slightly on the T-handle (see detail B, Figure 3-1) and press the release
spring at the bottom of the handle. The spring action pushes in the handle about 0.5
in.
WARNING Be careful not to pinch your fingers when releasing the spring. Thespring moves toward and into the collar when released.
7. Rotate the T-handle 90° in either direction. When the handle reaches the 90°position, the release snaps into the locking position as shown in detail C of
Figure 3-1.8. Push in the spring-loaded release rod until it bottoms. See detail D of Figure 3-1.
The spring-loaded release rod pushes in the button on the connector so that the
button clears the housing.
Note You may need to push in the T-handle to relieve pressure on the release rod.
CAUTION When removing the connector from the housing, be sure to hold in the spring-loaded
release rod until the entire insertion and removal tool has cleared the housing. Releasing
the rod too soon could cause the button on the connector to damage the inner housing.
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07/97 770.00696-NW Disassembly and Assembly 3-3
RELEASE ROD
RELEASE SPRING
ALIGNMENT SLOT
DITS BUTTONA INSERTION / REMOVAL TOOL
B
C
D
E
Figure 3 -1: Removing the DITS Connector from the Pressure Housing
9. With the release rod pushed in to its maximum depth, pull on the T-handle to ease
the electronics chassis out of the housing. As soon as the button on the connector
clears the housing, the release rod springs back into the locking position. Support the
I beam as it is removed.
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3-4 Disassembly and Assembly 770.00696-NW 07/97
Basic DITS Assembly
Electronics and Directional Sub
Use the appropriate engineering drawings for reference when assembling the tool section
assembly.
1. Adjust the T-handle on the insertion and removal tool to draw the three tabs into the
cylinder. See detail A of Figure 3-2.
2. Align the wide slot of the insertion and removal tool with the tabs on the connector.
See detail A of Figure 3-2.
3. While holding the insertion and removal tool and connector together in one hand,
use the other hand to pull back slightly on the T-handle and press the release spring
(see detail B of Figure 3-2) to let the T-handle move forward.
WARNING Be careful not to pinch your fingers when releasing the spring. Thespring moves forward and into the collar when released.
Turn the T-handle 90° in either direction to lock the insertion and removal tool to the
connector. See detail B of Figure 3-2.
4. Carefully match the alignment slot on the collar of the insertion and removal tool
with the slot on the housing. See detail B of Figure 3-2.
Figure 3 -2: Installing the DITS Connector into the Housing
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07/97 770.00696-NW Disassembly and Assembly 3-5
5. Push in the release rod in to maximum depth, and hold it so that the button on the
connector does not damage the inside of the housing. Push the connector, with the
electronics chassis attached, into the housing. (See detail C of Figure 3-2.)
Note Make sure the button on the connector (spring loaded) is locked into the proper
position before releasing the insertion and removal tool.
CAUTION When you are inserting the connector into the housing, be sure to hold in the spring-
loaded release rod until the entire insertion and removal tool has cleared the housing.
Releasing the rod too soon could cause the button on the connector to damage the inner
housing.
6. With the release rod pushed in to maximum depth, press the release spring at the
bottom of the T-handle, and rotate the handle to place the spring below the T-handle.
7. Carefully pull the insertion and removal tool out of the housing.
Disassembly of the Cast-V Scanner
Reference Drawings
• Scanner assembly - 707.55531
• Housing assembly - 707.55532
• Motor assembly - 707.55530
Note Oil inside the scanner is at low pressure. Remove the oil plug slowly and shield
any oil spray with a rag.
Oil Drain
Remove the lower oil-fill plug on the scanner body (Loc. 25) and drain the oil. Remove
the upper oil-fill plug and check the valve (Loc. 25 and 47).
Transducer Holder Removal
Refer to drawing 707.55532.
1. Remove the head by loosening three set screws (Loc. 70) and unscrewing the collar
(Loc. 66). Remove the head carefully to avoid damaging the transducer leads.
2. Remove the terminal board (Loc. 73) and unplug the slip-ring wires.
3. Remove the head base and collar by removing the socket head cap screws (Loc. 71).
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3-6 Disassembly and Assembly 770.00696-NW 07/97
Face Seal Removal
Using an 18-in. crescent wrench, remove the seal retainer (Loc. 63). Carefully remove
the face seal assembly (Loc. 62) and spacer (Loc. 60). Take special care to avoid
damaging the face seal mating surfaces.
Housing DisassemblyNote The keys (Loc. 17) are threaded 5/16-18-UNC inside the two bolt holes. Thread a
bolt into these threads to aid in removal of the key.
1. Remove the cap screws and keys at the top of the tool (Loc. 17 and 18), and separate
the DITS sub (Loc. 16) from the keyed housing (Loc. 23).
2. Remove the small retaining ring on the hermetic connector (Loc. 20) to remove the
insulating wafer. Pull straight out on the wire bundle to unplug the wafer. Unsolder
the sockets, and remove the wafer.
3. Remove the bolts and keys (Loc. 17 and 18) and separate the keyed housing (Loc.
23) from the motor housing (Loc. 37). Carefully pull the wire bundle from the keyedhousing.
Mud-Cell Removal
To remove the mud cell transducer (Loc. 31) use tool P/N 707.55578, and unscrew the
threaded ring (Loc. 36). Using a 4-in. long 1/4-20 bolt or all-thread, remove the backup
plate (Loc. 35) and the wave-washer (Loc. 33). Gently push or tap on the front face of
the transducer to remove it.
Motor Assembly Removal1. Remove the bottom set of keys and bolts (Loc. 17 and 18) and carefully remove the
motor, slip ring, and keyed sub assembly.
2. Unsolder wires from terminals (Loc. 48) and loosen the coupling set screws (Loc.
50). Remove the motor-resolver assembly (Loc. 38) from motor mount (Loc. 49) by
removing the four screws (Loc. 75) from the motor mount.
Slip-Ring Removal
Remove the four screws (Loc. 75) attaching the motor mount (Loc. 49) to the keyed sub
(Loc. 59) and remove the mount. Remove coupling (Loc. 50) and pin (Loc. 51) from theslip-ring (Loc. 54) and shaft (Loc. 58). Carefully slide the slip-ring off the shaft while
removing the wires from the shaft bore.
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07/97 770.00696-NW Disassembly and Assembly 3-7
Shaft and Bearing Removal
Use tool P/N 707.55578 to remove the two threaded rings (Loc. 56) from the keyed sub
(Loc. 59). Remove the shaft (Loc. 58) by lightly tapping on the end of the shaft with a
rubber mallet. The shaft drops out with one bearing attached. Remove the other bearing
in the keyed sub.
Assembly of the Cast-V Scanner
WARNING Do not use O-Lube on components during assembly. It is notcompatible with Turbo Oil.
Note All seals, except where noted, are to be lubricated with Exxon Turbo oil 2380.
Use Loctite #242 on all screws unless otherwise noted. Use Loctite #620 only where
noted because of high strength.
Motor-Resolver Assembly
Refer to drawing 707.55530.
1. Mount the resolver assembly on the end of the motor that contains the motor wires.
2. Loctite the keystock (Loc. 2) onto the motor shaft. Install, but do not Loctite, the
extension shaft (Loc. 6) onto the motor shaft.
3. Loctite the resolver rotor (Loc. 1) to the extension shaft (Loc. 6) using Loctite #620,
and push the rotor on until the end of the extension shaft is flush with the top end of the rotor. Use the keystock (Loc. 2) to align the resolver rotor and shaft.
4. Install the resolver mount (Loc. 5) to the motor as shown on 707.55530. Install but
do not tighten the two screws (Loc. 7) in the extension shaft. Install the resolver
stator.
5. Install the resolver retainers (Loc. 3), making sure they are flush with the OD of the
resolver mount (Loc. 5). They must lock into the groove on the OD of the stator.
6. Using a thin-bladed screwdriver, adjust the extension shaft through the 0.5-in. hole
in the resolver mount so that the top of the magnets in the rotor are exactly flush
with the top of the magnets in the resolver stator. Tighten the screws (Loc. 7) to
secure.7. Refer to setup procedure 770.00103 for resolver adjustment.
8. When properly set, the resolver rotates the motor shaft clockwise when seen
downhole.
9. Install the resolver cover (Loc. 9).
10. Wire the motor and resolver according to the wiring diagram on drawing 707.55532.
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3-8 Disassembly and Assembly 770.00696-NW 07/97
Motor Mount Assembly
Refer to drawing 707.55532.
1. Loctite the dowel pins (Loc. 46 and 52) to the motor mount (Loc. 49).
2. Install the eight terminal studs (Loc. 48).
3. Loctite the keystock (Loc. 53) to the motor shaft keyway.4. Slide the flexible coupling (Loc. 50) onto the motor shaft but do not tighten the set
screw.
5. Bolt the motor mount (Loc. 49) to the motor (Loc. 38).
6. Adjust the coupling so that the set screw is visible through the mount access hole
under the solder terminals. Tighten the coupling to the motor shaft.
Shaft Assembly
Refer to drawing 707.55532.
1. Loctite the dowel pin (Loc. 46) to the scanner shaft (Loc. 58) and the keyed sub
(Loc. 59).
2. Using a scribe or pick, remove the snap ring and shields from each side of the
bearings (Loc. 57). Clean out the packing grease, but do not spin the bearing dry
with shop air. Lubricate the bearings with Turbo oil.
CAUTION Do not use the threaded retainer ring (Loc. 56) to seat the bearings (Loc. 57) in the keyed
sub (Loc. 59). Use the bearing installation tool. Do not thread the retainer rings by hand
into the sub before installation of the shaft. If the retainer ring does not thread to bottom
easily, check the threads for burrs, especially around the area where the milled slot and the
threads meet. Use a small three-cornered file to clean the threads.
3. Use bearing installation tool 707.55615 to install the lower (downhole) bearing (Loc.
57) in the keyed sub (Loc. 59). Thread the retaining ring (Loc. 56) in place by hand.
4. Install the shaft (Loc. 58) into the sub.
5. Install the upper bearing (Loc. 57) onto the shaft and seat in the sub. Install the
retaining ring. Tighten both retainer rings using assembly tool 707.55578. Use hand
torque only. Do not wrench on this tool. Lock the rings in place by using a center
punch to stake or lock the threads of the ring to the mating threads of the sub. This is
done by center punching the ring on the top face near the thread area. Do not center
punch the keyed sub surface.
6. Install the O-ring (Loc. 55).
Slip-Ring Installation
Refer to drawing 707.55532.
1. Locate the slip-ring (Loc. 54), and slide a 2-in. long piece of shrink tubing over each
wire that exits the center rotor. Slide the tubing up to the rotor housing, and shrink with
heat.
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07/97 770.00696-NW Disassembly and Assembly 3-9
2. Remove the existing vendor wire labels, and label each wire with markers from the
package (P/N .60009). Cover with clear shrink tubing to retain.
3. Install the slip-ring assembly onto the scanner shaft, and note the position to line up the
3/32-in. hole in the slip-ring hub with the hole in the shaft. Route each wire through the
angled holes in the shaft and out the end so that the labels are visible.
4. Secure the slip-ring to the shaft with pin (Loc. 51). Be careful if pulling the slip-ring
wires out the ID of the shaft so as to not nick or cut the wires.
5. Trim the wires 2-in. from the end of the shaft.
6. Loctite the keystock (Loc. 53) to the shaft.
7. Line up the slot on the OD of the slip-ring body with the dowel pin (Loc. 52) on the
motor mount. Align the shaft with the coupling, and route the wires from the slip-ring
through the 1-in. hole in the motor mount.
8. Bolt the keyed sub and the motor mount together using screws (Loc. 75).
9. Tighten the coupling screws (Loc. 50).
10. Solder the slip-ring wires in numerical order to the terminals. Secure the wires with
high-temperature lacing cord.
Face Seal Installation
Refer to drawing 707.55532).
CAUTION Use extreme care when handling the face seal components. Scratches on the sealing
surfaces cause the seal to leak oil.
1. Lightly lubricate the seal end of the shaft as well as the ID of the rubber bellows (Loc.
62) with S.T.P. Oil Treatment (P/N .22933). Install the seal spacer (Loc. 60) over the
output end of the shaft with the short end facing downhole. Slide the seal assembly
(Loc. 62) (spring and bellows assembly) onto the shaft. Slide the seal along the shaft
several times to ensure the rubber bellows seal lip has not rolled on the shaft.
CAUTION The primary ring must be installed correctly. The tapered end must face downhole to
contact the polished surface of the mating ring.
2. Locate the primary ring, and apply a thin film of silicon grease to the back face of
the ring. Install the primary ring over the shaft, and align the notches on the ring
with ears on the bellows retainer. The grease contacts the rubber bellows, keeping
the primary ring secure against the bellows assembly.
3. Apply a thin film of Turbo Oil to the face of the primary ring.
4. Lubricate the mating ring face and O-ring (Loc. 72) with Turbo Oil and install in the
retainer (Loc. 63) with the polished face uphole toward the primary ring and bellows
assembly.
5. Install the O-ring (Loc. 61) onto the retainer. Thread the retainer in the keyed sub
and tighten.
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3-10 Disassembly and Assembly 770.00696-NW 07/97
Keyed Sub and Motor Housing Assembly
Refer to drawing 707.55532.
1. Loctite the three dowel pins (Loc. 67) in place, and install the O-rings (Loc. 68 and
69) in the head base (Loc. 65).
2. Slip the collar (Loc. 66) over the base, and pull the slip-ring wires through the hole
in the center of the base (Loc. 65). Align the dowel pin (Loc. 46) and install the baseto the scanner shaft (Loc. 58) with the four screws and lock washers (Loc. 71 and
85). Use Loctite #290 on these screws.
3. Solder the pins (Loc. 86) to the slip-ring wires according to Note 17 on the drawing
and plug the wires into the correct numbered socket on the terminal board (Loc. 73).
Cover both the pin and socket with a length of shrink tubing according to Note 18 on
the drawing.
4. Secure the slip-ring wires to the motor OD with high-temperature lacing cord
according to Note 15 on the drawing.
5. Slide the motor assembly into the motor housing (Loc. 37), and align the grooves on
the OD of both housings.6. Install the keys (Loc. 17) using the bolts (Loc. 18).
Mud-Cell Assembly
Refer to drawing 707.55532.
1. Install the O-ring (Loc. 30) onto the mud-cell transducer (Loc. 31) and solder a 24-in.
length of wire (according to the wiring diagram). Cover the joint with RTV.
2. Install the transducer into the housing (Loc. 23) according to the drawing.
3. Install the transducer protector plate (Loc. 32), the wave spring (Loc. 33), and thebackup plate (Loc. 35). A small amount of silicon grease holds the wave spring to the
backup plate during installation. The transducer wires pass through the slot in the
bottom of the backup plate. The dowel pin aligns in the slot in the back of the
transducer.
4. Thread the retainer ring (Loc. 36) in place (the transducer wires must pass through the
center of the retainer ring), and tighten the ring with assembly tool 707.55578. Route
the wires according to notes on the wiring diagram.
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07/97 770.00696-NW Disassembly and Assembly 3-11
Pressure Balance Assembly
Refer to drawing 707.55532.
Note The CGT ring assembly (Loc. 43) must be properly sized before installation into the
pressure balance cylinder (Loc. 40).
1. The CGT ring seal assembly consists of three parts: the two backup rings, the energizer
ring, and the cap seal. See Figure 3-3. Install the energizer ring and the two backup
rings onto the piston (Loc. 42). Place the cap seal into boiling water, and allow it to
soak for approximately 1 min. Remove the cap seal from the water, and carefully
stretch it over the piston and onto the top of the energizer ring and between the backup
rings. Use a piece of lacing cord to stretch and work the cap seal over the piston, but do
not overstretch. After the cap seal is located over the energizer ring, carefully squeeze
the cap seal with your hand to form-fit it around the energizer ring.
CAUTION Insure that the piston is square with the cylinder before insertion. If not square, the cap seal
will be damaged. If the piston is square with the cylinder, the piston slides into the cylinder
easily.
2. Place the piston assembly, without slydring (Loc. 41) installed, into cold water for
about 1 min. Lubricate the ID and ends of sizing cylinder 707.55624 with Turbo Oil
and carefully slide the piston assembly, seal end first, into one end of the cylinder.
Allow this assembly to sit for about 1 min and then remove the piston from the sizing
cylinder, and install the slydring (Loc. 41). Install the piston assembly into the pressure
balance cylinder (Loc. 40) as shown on the drawing.
3. Install the O-rings (Loc. 24 and 27) onto the piston compensator sub (Loc. 39).
4. Thread the sub (Loc. 39) into the cylinder (Loc. 40), and tighten it.
Note The pressure balance cylinder (Loc. 40) is thin-walled material. Do not clamp or
wrench on the OD.
5. Place the spring (Loc. 44) on the back side of the piston and screw on the spring
retainer (Loc. 45). Carefully thread this assembly into the housing (Loc. 23), and
tighten.
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3-12 Disassembly and Assembly 770.00696-NW 07/97
Slydring
Backup Ring
Energizer Ring
Cap Seal
Figure 3 -3: Piston Seals
Motor Assembly and Keyed Housing Assembly
Refer to drawing 707.55532.
1. Route the wires from the motor section through one of two small holes in the keyed
housing. See the wiring diagram for details.
Note The resolver wires must be routed separate from the motor wires.
2. Carefully mate the two housings aligning the grooves on both housings. Install the
keys and bolts (Loc. 17 and 18).
DITS Upper Sub Assembly
Refer to drawing 707.55532.
1. Route the color-coded wire from the motor-resolver assembly through the properly
numbered hole in the hermetic connector wafer, and solder onto the socket. See the
wiring diagram.
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07/97 770.00696-NW Disassembly and Assembly 3-13
2. Install the O-rings (Loc. 68) onto the hermetic connector (Loc. 20) and seat the
connector in the housing.
3. Install the retaining ring (Loc. 22).
4. Install the O-ring (Loc. 21) onto the sub and install the DITS hardware. Wire the
DITS connector to the hermetic connector according to the wiring diagram.
5. Plug the wafer from the motor assembly into the hermetic, and install the waferretaining clip.
6. Complete the wiring according to the wiring diagram.
7. Mate the upper sub to the motor assembly, and install the two keys and cap screws.
Holder and Transducer Assembly
Refer to drawing 707.55531.
1. Refer to assembly drawing 707.55531 for the holder and transducer selection and
installation.
2. Plug the transducer leads to the proper socket on the terminal board (Loc. 73), and
cover both the pin and socket with a piece of shrink tubing.
Oil-Fill Procedure1. There are two evacuation ports on the scanner body and one on the transducer
holder. The upper port on the housing is threaded deeply for a removable check
valve (Loc. 47) as shown on drawing 707.55532. Remove the check valve assembly
when evacuating the tool.
2. Install three oil-fill tubes (P/N 707.55581), and evacuate the tool. Then fill the tool
with Exxon Turbo Oil (P/N .81792) according to Specification 770.00013.
WARNING Do not apply silicon grease around the shaft to seal a vacuum leak atthe face seal. The vacuum leak sucks the grease inside the tool anddamages the sealing surfaces of the face seal. If a leak persists,remove the fill-tube at the bottom of the head, and install the oil plug.Stand the tool vertically with the head in a large can filled with TurboOil. The oil level must completely cover the face seal area. Securethe tool vertically, and continue evacuation.
3. After the tool is oil filled, remove the fill tubes and replace the lower scanner plug
(Loc. 25) and head plug. Install the check valve (Loc. 47) in the upper fill port, andreinstall a fill tube.
Note The check valve must bottom out in the housing to allow room for the plug to be
installed above it.
4. Install a piece of ¼-in. Tygon tubing (or similar tubing) to a hand-pressure pump
filled with Turbo oil. Stroke the pump several times to bleed any air out of the
tubing, and top off the fill tube with oil. Secure the tubing to the fill tube with a
small hose clamp.
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3-14 Disassembly and Assembly 770.00696-NW 07/97
5. Pump the piston back with oil until the score mark on the oil fill gage P/N 707.55673
is aligned with the inside face of the spring cap (Loc. 45). See Figure 3-4 and
drawing 707.55531 for piston set dimensions and gage position.
6. Bleed the pressure off the pump. Remove the oil-fill tube, and install the fill port
plug. It is not uncommon for the check valve to leak a small amount of oil. If the
check valve leaks excessively and does not hold pressure, then remove it and clean
out the valve by depressing the ball and blowing air or soaking the valve in solventto remove any debris between the ball and seat. If the valve continues to leak, use a
small brass flat tip punch to strike the ball from the washer and spring side. Striking
the ball increases the seat sealing area. If the check valve continues to leak
excessively, remove and wrap the threads with Teflon tape. Wrap only the thread
area, and trim away any excess tape.
7. Install the cover (Loc. 28).
OIL FILL GAGE
GAGE MARK
Figure 3 -4: Piston Gage Position
Pressure and Temperature Test
Note This test is for Fort Worth Manufacturing only.
WARNING Do not pressure test the scanner in cold water. Such testing couldcause the transducers to fail.
1. Install the scanner in the chamber.
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07/97 770.00696-NW Disassembly and Assembly 3-15
2. Ramp temperature and pressure to 175°F and 10,000 psi, according to Section 5,
Paragraph 3 of Halliburton Engineering Specification 770.10012.
3. Stabilize the temperature and pressure. Hold these settings for 10 min.
4. When the chamber internal temperature has dropped 125°F or below, the chamber
pressure can be reduced to ambient pressure and the tool removed.
Adjustment of the Motor/Resolver AssemblyThis section provides instructions for positioning the resolver in the motor-resolver
assembly 707.55530.
Equipment Required• CAST-V electronics or simulator board
• DC power supply (current capacity at least 1.0 A)
• Oscilloscope
• 120-Vac, 60-Hz supply
Reference Drawings• 707.55530 Motor Assembly - Scanner
• 707.55567 Modification - Chassis Assembly - DITS CAST to CAST-V
• 707.55595 Chassis Assembly - Electronics - CAST-V
Procedure
Note This procedure is intended to be used with the motor-resolver assembly
707.55530 with no additional hardware attached to the output shaft of the motor.
After the resolver has been mounted to the motor, resolver wires REFA (RED/WHT),
SIN (RED), COS (BLU), and RGND (BLK, YEL & YEL/WHT) are connected to the
CAST-V electronics chassis (refer to Figure 3-5) with connector pins P1-21, P1-14,
P1-15, and P1-22, respectively.
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3-16 Disassembly and Assembly 770.00696-NW 07/97
BLU
RED/WHT
Motor
1 Ampere Capacity Bench Supply20 Vdc Maximum
P1-14
P1-22
P1-15
P1-21
(RGND)
(RGND)
YEL/WHT
YEL
BLK
Resolver
MOT2BLK
MOT1RED
MOT3GRN
(SIN)RED
(RGND)(COS)
(REFA)
INSTRUMENTPOWERSOURCE
PIN 13PIN 14
AC VoltageInput
VariableVoltage
Transformer
IsolationTransformer
V40 DSPDATAACQ.
PREAMP/FIRE
– +
Figure 3 -5: Setup Connections for Resolver Adjustment with the CAST Tool
If the simulator board is used, make the resolver connections as shown in Figure 3-6.
Figure 3 -6: Setup Connections for Resolver Adjustment with the Simulator Board
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07/97 770.00696-NW Disassembly and Assembly 3-17
Fixed Position Alignment
The following steps align the motor rotor and stator to a fixed position. This fixed
position ensures that the commutation sequence and direction of rotation is correct.
1. Rotate the rotor by hand until the rotor keyway is aligned with the orientation hole
located under the resolver mounting flange (Figure 3-7).
MOTOR HOUSING
RESOLVERSTATOR
WIRES
Figure 3 -7: Relationship of the Keyway to the Orientation Hole at Electrical Zero
2. Connect motor wires 2 (BLK) and 3 (GRN) together.
3. Using a dc power supply with sufficient current capacity (> 1.0 A), connect motor
wire 1 (RED) to the positive terminal, and connect motor wires 2 (BLK) and
3 (GRN) to the negative terminal.
CAUTION Motor windings have low resistance and require less than 8 V to develop 1 A of current.
Keep the current below 1.5 A.
4. Turn on the dc power supply. Apply 1 A to the motor to lock the rotor in place. The
rotor keyway aligns exactly with the motor orientation hole upon the application of
power. The motor rotor and stator are now aligned. Proceed immediately to Step 3
while maintaining power to the motor.
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3-18 Disassembly and Assembly 770.00696-NW 07/97
Electrical Zero Alignment
The following steps align the resolver stator with the resolver rotor to obtain electrical
zero (EZ). At EZ, a +5-V pulse is generated at pin U1-35 on the R-to-D board
707.55561.
1. Use a scope probe to monitor the voltage level at U1-35 on the R-to-D board. Set the
scope to AUTO TRIGGER to view only the steady-state dc level at this pin.
2. Rotate the resolver stator by hand until the voltage at U1-35 shifts to +5-V as
observed on the scope.
3. While maintaining the voltage level at +5-V, tighten the clamps that hold the
resolver stator in place. The +5-V output voltage is sensitive to the orientation of the
resolver rotor and stator.
4. Turn off the dc motor power supply and the ac tool power supply.
5. Disconnect the motor wires from the dc power supply. Separate motor wires 2
(BLK) and 3 (GRN). Connect all three motor wires to the tool chassis by P1, as
shown in Figure 3-8, or to the simulator board as shown in Figure 3-9.
BLU
RED/WHT
Motor
1 Ampere (or Greater) Capacity0 to 150 Vdc Maximum
P1-14
P1-22
P1-15
P1-21
(RGND)
(RGND)
YEL/WHT
YEL
BLK
Resolver
(SIN)RED
(RGND)
(COS)
(REFA)
INSTRUMENTPOWERSOURCE
PIN 13PIN 14
AC VoltageInput
VariableVoltage
Transformer
IsolationTransformer
V40
MOT + MOT –
DSPDATA
ACQ.PREAMP/FIRE
+ –
P1-36
P1-35
P1-37
MOT2BLK
MOT1RED
MOT3GRN
Figure 3 -8: Run Connections for the Motor with the CAST Tool
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07/97 770.00696-NW Disassembly and Assembly 3-19
– +
+
RATE0TACHRATE2RATE1START
Resolver
Motor
COMMUTATORJ1-15
J2-5 J1-9
J2-10
J1-13
J2-4 J1-8
J2-9
J1-12
J2-3J2-15
J1-3
J2-8
J1-8
J2-2J2-14
J1-2
J2-7 J1-15
J1-6
J2-1J2-13
J1-1
J2-6 J1-10
-15+15+5GND
POWER SUPPLY
COS
SIN
RGND
REFAORG
YEL
GRN
BLU RED
BLK,YEL,YEL/WHT (3 WIRES)
BLU
RED/WHT
150uF
J 3 7
J 3 7
J 3 8
J 3 8
J 3 9
J 3 9
J 3 6
J 3 2
J 3 5
J 3 1
Power Supply0 to 150 Vdc at 1 amp
MOT A+MOT A –
MOT B+
REF A
COS
RGND
SIN
MOT B–
MOT C+
MOT C–
BLK
RED
GRN
MOT2
MOT1
MOT3
WHT/YEL
WHT/ORN
WHT/RED
Figure 3 -9: Run Connections for the Resolver Setup with the Simulator Board
CAUTION When examining signals on the commutator board do not touch the chassis while
touching the case of transistors Q1, Q4, or Q7. The commutator drive waveform will
become unbalanced, allowing high surge currents to blow FETs.
Turn on the tool power (120-Vac). As a quick check to monitor the EZ setting, rotate the
rotor by hand until the rotor keyway is roughly aligned with the orientation hole under
the resolver mounting flange (refer to Figure 3-7). As previously in Step 3, monitor the
EZ voltage with an oscilloscope or voltmeter. As the rotor keyway passes through the
location of the orientation hole, there should be a +5-Vdc pulse at U1-35 on the R-to-D
board (707.55561).
Note This step is only meant to serve as a visual check. However, if the angular
difference between the rotor keyway and the orientation hole is noticeable when the +5-
V pulse occurs, loosen the resolver stator clamps, and repeat Steps 3 through 5.
Apply dc motor power sparingly. The motor begins to spin at around 3-Vdc.
Note Do not spin the motor at high speeds or for an extended time at low speeds.
Motor bearings are only lightly lubricated. This spinning could damage bearings.
Motor-resolver setup is now complete. Disconnect the motor and resolver wires from the
electronics, and complete the assembly of the scanner.
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Halliburton Energy Services
07/97 770.00696-NW Calibration and Verification 4-1
Calibration and Verification
IntroductionThis section contains instructions on calibration.
Calibration of the Directional SubThis subsection discusses the calibration and testing of directional sub chassis assembly
(707.55562) used in directional sub assembly (707.55572).
General
The directional sub for the CAST-V tool contains a biaxial inclinometer (707.30905), atwo-axis magnetometer sensor assembly (.77800), and a compass board (707.55574).
Power is obtained from the CAST-V electronics package. All output signals from the
directional sub are near dc and are further processed at the slow ADC board in the
CAST-V electronics package.
Several FA on the compass board require adjustment for calibration of the
magnetometer. FA values must be adjusted with the same sensor assembly connected to
the board as to be used in the finished tool.
Biaxial inclinometer adjustments at the compass board consist of two FAs. The
inclinometer itself is a purchased item requiring no internal adjustments. The
inclinometer adjustments on the compass board match the signal level from the
inclinometer to the ADC measurement range.
After calibration, a heat run is made to 175°C with the directional chassis in a heated
sleeve so that the chassis can be rotated and tilted as heat is applied. Data are recorded
for QC files at this time.
Section
4
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4-2 Calibration and Verification 770.00696-NW 07/97
Equipment
This calibration procedure is accomplished without the CAST-V electronics, but with
standard lab test equipment for all measurements. Equipment required is as follows:
• power supply, ±15-Vdc at 100 mA, metered
• digital voltmeter, 4 ½-in. digits
• calibration stand assembly (707.55635)
• 37-pin DITS connector to mate to top of tool with leads for testing
• ohmmeter (Triplet 630 NS or equivalent)
• electrically heated sleeve for the chassis which will mount in test stand
• oscilloscope
• gaussmeter (necessary only if local earth flux levels are unknown).
Magnetometer AdjustmentCalibration must be done in a building with no substantial amount of iron or steel. The
flux field of the earth must be parallel throughout the space that the tool measures. This
procedure assumes a normal (approximately 0.5-gauss) magnetic field strength.
Many of the adjustments depend on the exact characteristics of the sensor assembly and
its precise orientation to the earth's magnetic field. Therefore, the compass board cannot
be adjusted correctly without a calibration stand assembly.
The test stand must be aligned with magnetic north. Use a magnetic compass held at the
approximate position of the sensor assembly for reference. When the stand is locked in a
vertical position, the fixed pointer on the rotating protractor (as opposed to the fixed
deviation, or tilt, protractor) points directly at magnetic north.
Install the directional chassis into the test stand as shown in Figure 4-1. Ensure that the
DITS button on the chassis assembly is aligned with the "0 degree" mark on the
protractor, which measures the rotation of the tool. At this point, the DITS button of a
chassis installed in the stand faces exactly north when zero on the protractor is set to the
fixed pointer of the stand. Hang the compass board loose on the wiring harness so that
the adjustments are accessible. Connect the wiring to the meters and power supplies, as
shown in Figure 4-2.
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07/97 770.00696-NW Calibration and Verification 4-3
707.71547
707.55619
.86540
707.55562
707.5561.11346 (3)
Figure 4 -1: Test Stand Setup
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4-4 Calibration and Verification 770.00696-NW 07/97
Figure 4 -2: Test Setup Wiring
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07/97 770.00696-NW Calibration and Verification 4-5
Adjustment Procedure
The following procedure is used to adjust the compass board. The sensor drive signal is
adjusted first. Then the amplifiers and other electronics are adjusted to condition the
signals from the sense coils.
1. Temporary resistors should be installed in all FA slots. Approximate values are as
follows:
• R37 = 1740 Ω
• R19 = 13 k Ω
• R20 = 13 k Ω
• R18 = 10 k Ω
• R1 = 10 k Ω
• R11 = 20 k Ω
2. Apply power while observing current from the supply:
• Positive supply current should be < 45 mA.• Negative supply current should be < 40 mA.
Note Current varies with the position of the chassis. Position the chassis horizontally,
and rotate 360° while watching the current meter. Use the largest current reading seen
during the rotation.
3. Adjust the frequency of U3 (connect a counter or scope to either end of R42) by
adjusting FA resistor R37. Set the frequency should to 27 ± 2 kHz.
4. Refer to the waveforms in Figure 4-3. The OSCOUT (U3-4) triggers the one-shot
U6/A. The trailing edge of U6/A-6 triggers U6/B, which generates a negative-goingpulse timed to encompass the moment of saturation of the sensor. The saturation is
visible with a scope connected to TP-1. The negative-going pulse is visible with a
scope connected to TP-5. It is not necessary to exactly center the moment of
saturation in the TP-5 pulse. If the timing and the position of the gate look good,
then proceed.
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4-6 Calibration and Verification 770.00696-NW 07/97
Figure 4 -3: Gate Timing Relationships on the Compass Board
5. Compare output waveforms at TP-2 and TP-4 to Figure 4-4, trace B. Rotating the
tool changes the amplitude and polarity, but the waveshape should be similar. An
exact match is not required, but if the waveforms are not similar, problems will arise
later in this procedure.
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07/97 770.00696-NW Calibration and Verification 4-7
Figure 4 -4: Signal Waveforms on the Compass Board.
6. Measure dc voltage at the positive lead of TP-6. The voltage at TP-6 should be 9- to
12-Vdc.
Note "J1" refers to the upper 37-pin DITS connector of the directional sub.
As the chassis is rotated, an ideal plot of MAGX and MAGY output voltages (measured
with a digital voltmeter at J1-25 and J1-24) shows sine and cosine waveforms
symmetrical about ground. To get closer to ideal, adjust the peak amplitudes of MAGX
and MAGY to get the same peak voltage for positive and negative swings.
7. Rotate the chassis assembly through a full 360° and note the polarity and amplitude
of the output signal at MAGX (J1-25). Locate the point in the rotation where the
amplitude peaks, and note the voltage. Rotate the coils 180° to the opposite peak
polarity, and again note the voltage. These two voltages differ a little in amplitude.
Adjust R19 FA until the opposite polarity peak voltages are the same magnitude.
Repeat the adjustment procedure until the symmetry is correct (1% match is usually
obtainable).
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4-8 Calibration and Verification 770.00696-NW 07/97
Note Ensure that the positive peak of the MAGX (J1-25) voltage occurs when the
DITS button is pointed north (near 0°).
8. Switch the voltmeter to MAGY (J1-24). Once again rotate the chassis assembly, and
note the peak voltage swings. Set R20 FA to adjust the voltage swings to obtain
equal plus and minus peak readings. When symmetry has been established, note the
peak positive voltage for use in the next step.
Note Ensure that the peak positive MAGY (J1-24) voltage swing occurs when the
chassis is rotated to near 90°.
9. Switch the voltmeter to MAGX (J1-25), and rotate the chassis to get a peak positive
output. Use R11 FA to set the amplitude of the peak voltage to the same as was
recorded in Step 8.
Rotation of the chassis assembly yields the same plus and minus voltage peak swings out
of MAGX and MAGY. All that remains is to electrically rotate the output of MAGY to
be exactly 90° from the zero of MAGX.
10. Connect a digital voltmeter to MAGY (J1-24). Rotate the chassis assembly to get
zero volts on the meter. Set the movable pointer on the rotating protractor to a
convenient reference point (0 degrees or 180 degrees).
11. Connect the digital voltmeter to MAGX (J1-25). Rotate the chassis assembly until
the voltmeter reads zero. This point should occur exactly 90° from the point of
rotation noted in step 10. The zero point is probably off from the point noted in Step
10 by 90° plus or minus a few degrees (an error of 5° or less is expected). Adjust R1
FA until the MAGX zero point occurs exactly 90° from the MAGY zero as noted in
Step 10.
Recheck of Magnetometer Adjustment
To recheck the magnetometer adjustments, rotate the chassis assembly in the test standwhile observing that:
1. The peak amplitude for plus and minus output of each axis is near the same peak
voltage.
2. The 0-V point for the MAGX (J1-25) occurs at 90° from the 0-V point of the MAGY
(J1-24).
3. The MAGX and MAGY output voltages are equal when the test stand protractor
indicates 45 ± 1° from the MAGY zero.
Install the compass board in the chassis. Rotate the chassis until the DITS button points
to magnetic north 0° on the protractor). Loosen the fasteners (Loc. 34 on drawing
707.55562), and adjust the position of the sensor to get 0 V out of the MAGY (J1-24)output. Tighten the fasteners after adjustment is complete.
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07/97 770.00696-NW Calibration and Verification 4-9
Inclinometer Adjustment
The purpose of this section is to provide instructions on test stand setup to hold the
chassis horizontal.
Adjustment Procedure
1. Apply power, and meter the INCLX (J1-26) and INCLY (J1-27) output voltages.
2. Rotate the chassis until the INCLX voltage peaks (either positive or negative). At
this point, adjust trim pot R10 to get exactly 4.00-Vdc output.
3. Rotate the chassis until the INCLY (J1-27) voltage peaks. Adjust R8 to get exactly
4.00-Vdc output.
Quality Control Data Collection (And Temperature
Testing)
Collect the data to be filed. Data collection consists of a series of voltmeter readingstaken at ambient temperatures followed by similar voltmeter readings taken with chassis
at 175°C. Enter each voltmeter reading into the data collection sheets provided or copies
of the sheet. The steps below outline the procedure used to complete the data sheets.
Page 1, Data Sheet Instructions
1. Using an ohmmeter, perform the continuity checks required for entries 1 through 13.
2. Install the chassis in the heated sleeve, but do not turn on sleeve power yet.
3. Connect power to the chassis and record the current drain from the ±15-Vdc supply
to the chassis.4. Record the peak voltage from the INCLX axis output (chassis horizontal and rotated
to get peak). INCLX peaks positive when the DITS button is up.
SPECIFICATION : INCLX peak voltage is 4.00 ±0.02-Vdc at ambient temperature.
5. Record the peak voltage from the INCLY output (chassis horizontal and rotated to
get peak. The maximum positive voltage occurs when the DITS button is rotated
clockwise 90°).
SPECIFICATION : INCLY peak voltage is 4.00 ±0.02-Vdc at ambient temperature.
Page 2, Data Sheet Instructions1. Adjust the chassis assembly to vertical, and set MAGY (J1-25) to 0-Vdc with the
DITS button pointing north. Adjust the pointer on the stand until it points to zero on
the protractor.
2. Rotate the chassis assembly, recording the MAGX (J1-25) and MAGY (J1-24)
voltages at 45° increments for a full rotation.
3. At each of the 45° increments, calculate the angle measured as shown below.
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4-10 Calibration and Verification 770.00696-NW 07/97
θ θ
θ φ=
××
+arctan
sin
cos
ΑΑ
,
where
A = peak amplitude of MAGX or MAGY
• ACos(θ) = MAGX = Signal at J1-25 (upper DITS connector)
• ASin(θ) = MAGY = Signal at J1-24 (upper DITS connector)
θ = angle measured from magnetic north
φ = rotator to place the angle in the right quadrant
The operator is obtained by examination of the polarity of the voltages seen at the
x-axis and y-axis output. For the magnetometer circuitry we are discussing, is
determined as follows:
• If MAGX is positive,
• and MAGY is positive, then = 0
• and MAGY is negative, then = 360
• If MAGX is negative,
• and MAGY is negative, then = 180
• and MAGY is positive, then = 180
The angle calculated from the voltages is recorded on the form provided.
SPECIFICATION : The calculated angle is < ±1.5° from protractor readings at ambient
temperature.
4. Measure the voltage at J1-28.
SPECIFICATION : The temperature sensor voltage at 25°C will be 1.36 ±0.1-Vdc. (If
the temperature at test is other than 25°C, correct at the rate of 0.005 V/ °C)
5. Heat the directional sub to 175°C and repeat Steps 1 through 4, using the elevated
temperature specifications below.
SPECIFICATION : At 175°C, the calculated angle will be < ±3° from ambient
protractor readings.
SPECIFICATION : The temperature sensor voltage at 175°C will be 2.24 ±0.1-Vdc.
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07/97 770.00696-NW Calibration and Verification 4-11
HALLIBURTON LOGGING SERVICES
QUALITY CONTROL RECORDS
DIRECTIONAL SUB
DIRECTIONAL SUB SERIAL No.____________________________
INCLINOMETER SERIAL No._______________________________
PROJECT No.___________________________________________
TECHNICIAN AT TEST____________________________________
DATE OF TEST__________________________________________
PAGE 1 OF 3
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4-12 Calibration and Verification 770.00696-NW 07/97
DATA COLLECTION SHEET
FOR DIRECTIONAL SUB
DC MEASUREMENTS AT AMBIENT
1. Continuity from J1-1 to P1-1 (Y/N) _____
2. Continuity from J1-2 to P1-2 (Y/N) _____
3. Continuity from J1-3 to P1-3 (Y/N) _____
4. Continuity from J1-4 to P1-4 (Y/N) _____
5. Continuity from J1-5 to P1-5 (Y/N) _____
6. Continuity from J1-6 to P1-6 (Y/N) _____
7. Continuity from J1-7 to P1-7 (Y/N) _____
8. Continuity from J1-8 to P1-8 (Y/N) _____
9. Continuity from J1-9 to P1-9 (Y/N) _____
10. Continuity from J1-10 to P1-10 (Y/N) _____
11. Continuity from J1-14 to P1-14 (Y/N) _____
12. Continuity from J1-15 to P1-15 (Y/N) _____
13. Continuity from J1-20 to P1-20 (Y/N) _____
14. Continuity from J1-21 to P1-21 (Y/N) _____
15. Continuity from J1-22 to P1-22 (Y/N) _____
16. Continuity from J1-35 to P1-35 (Y/N) _____
17. Continuity from J1-36 to P1-36 (Y/N) _____
18 Continuity from J1-37 to P1-37 (Y/N) _____
19. Current from +15-Vdc supply _____mA
20. Current from -15-Vdc supply _____mA
21. Inclinometer INCLX peak voltage _____Vdc
22. Inclinometer INCLY peak voltage _____Vdc
DIRECTIONAL SUB SERIAL No. INCLINOMETER SERIAL No.
________________________ ______________________
PAGE 2 OF 3
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07/97 770.00696-NW Calibration and Verification 4-13
DATA COLLECTION SHEET FOR
DIRECTIONAL SUB HEAT TEST
MAGX
Vout AMBIENT
MAGY
Vout AMBIENT
CALC.
ANGLE,DEG.
MAGX
Vout 175 °C
MAGY
Vout 175 °C
CALC.
ANGLE,DEG.
0 DEG
45 DEG
90 DEG
135 DEG
180 DEG
225 DEG
270 DEG
315 DEG
INC.
Vmax
N/A N/A
TEMP. N/A N/A N/A N/A
TECHNICIAN DATE
____________________________ __________________________
DIRECTIONAL SUB SERIAL No. INCLINOMETER SERIAL No.
___________________________ __________________________
PAGE 3 OF 3
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4-14 Calibration and Verification 770.00696-NW 07/97
Directional Sub CheckThe directional sub requires two types of measurement checks: a magnetometer
measurement check (the azimuth) and an inclinometer measurement check (the relative
bearing). The two-axis magnetometer measures the tool orientation with respect to
magnetic north, while the two-axis inclinometer measures tool orientation with respect
to the high side of hole, and hole deviation. Thus, setup the directional sub on the test
stand, powered up by the logging system, and place it in several positions so that
readings from the test stand and the logging system can be taken and compared.
Comparing the readings from the logging system and the test stand determines the
operating condition of the directional sub.
Test Stand Setup
Refer to Figure 4-5, and use the following steps to ensure the directional sub is operating
properly.
Figure 4 -5: Vertical Stand Position
1. Place test stand 707.71547 on a flat, smooth surface, far away from metal that might
disturb the earth’s magnetic field.
2. Using a compass, align the test stand with respect to magnetic north.
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07/97 770.00696-NW Calibration and Verification 4-15
3. Adjust the three screws at the base of the test stand until the stand is level using a
carpenter’s level or equivalent. Use the level to set the cradle vertically, and then set
the adjustable pointer on the semicircular disc to 0°.
Installing The Directional Sub Chassis
Install directional sub chassis assembly 707.55562 onto the test stand (see Figure 4-5).1. Install the adapter (707.55618) onto the test stand using three socket-head cap screws
(0.11346). Notice that the threads of these screws are metric.
2. Mount the directional sub chassis in the test stand by inserting the lower DITS
connector into the adapter (707.55618). Place the upper bracket (707.55619) over the
top DITS connector and clamp it to the test stand. Ensure that the chassis can be rotated
freely and that the top bracket is placed low enough on the tool to allow the jumper
cable to be plugged into the top of the directional sub.
3. Connect the 37-pin jumper cable (3.48659) from the top of the directional chassis and
to the bottom of the CAST-V electronics (707.55598). Use the standard 19-pin DITS
jumpers to connect the DSTU/D2TS and the cablehead to complete the toolstring.
4. Ensure that the EXCELL 2000 logging system is set up properly (refer to the EXCELL
2000 CLASS Logging System User’s Guide, 770.01032). Next, enter “Service Selection
2330” on the EXCELL 2000, and then select the DGR configuration to display
azimuth, relative bearing and deviation on the standard logging screen.
Magnetometer Check
Use the following to check the directional sub magnetometer.
1. Position the directional sub chassis and cradle to vertical with the pointer on the semi-
circular disc set to 0°.
2. Rotate the directional sub chassis and cradle until the fixed pointer on the cradle aligns
with 0° on the circular disc. The DITS button is now aligned with north, and the
logging screen displays 0 ±3 ° for AZIMUTH.
Note: If the value for the azimuth is not within ±3°, refer to the Directional Sub
Calibration Procedure (770.10566) for instructions on adjusting the magnetometer
circuitry. If the value of the azimuth is consistently off tolerance in the same direction (for
example, each reading is 3.5° clockwise of the true azimuth), then either the magnetometer
sensor is out of position, or the test stand is not oriented correctly. In either case, it may not
be necessary to go through the entire directional sub calibration procedure.
3. Rotate the directional sub chassis and cradle clockwise at 45° increments, and
compare the circular disc readings with the logging screen AZIMUTH readings. If
both readings are within ±3° at each increment, then the directional sub
magnetometer is functioning correctly.
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4-16 Calibration and Verification 770.00696-NW 07/97
Inclinometer Check
Use the following to check the directional sub inclinometer.
1. With the directional sub chassis and cradle still positioned to vertical (as in Step 3 of
Test Stand Setup), verify that the reading for DEVIATION on the logging screen
displays
0 ± 2°.2. Incline the directional sub chassis and cradle to 45° and then 90° (see Figure 4-6).
Compare the semi-circular disc reading to the logging screen DEVIATION reading for
each setting. The semicircular disc readings and the logging screen DEVIATION
readings should be within ±2°.
ADJUSTABLEPOINTER
SEMI-CIRCULAR
DISC
COUNTERCLOCKWISEINCLINATION
SOUTH NORTH
CIRCULARDISC
FIXED POINTER90°
Figure 4 -6 : Stand Position for 90-Degree Inclination
3. Incline the directional sub chassis and cradle to 5° on the semicircular disc (see
Figure 4-7) and rotate the directional sub and cradle to 0° on the circular disc. The
logging screen should display 0 ±2° for RELATIVE BEARING.
Note: The accuracy and stability of the relative bearing reading decreases in deviations
of less than 2°.
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07/97 770.00696-NW Calibration and Verification 4-17
Figure 4 -7 : Stand Position for 5-Degree Inclination
4. With the directional sub and cradle set at a 5° deviation, rotate the cradle circular disc
clockwise in 45° increments, and monitor the circular disc reading and the RELATIVE
BEARING reading on the logging screen at each increment. The circular disc readingsand the RELATIVE BEARING readings should agree within ±2°.
5. Repeat Step 4 at 45° and 90° deviations (counterclockwise from 5°). If the circular disc
readings and the logging screen RELATIVE BEARING readings are within ±2° for
each setting, then the directional sub inclinometers are functioning correctly.
Switch to the Processed Telemetry Logging Screen, and verify that the temperature as
indicated on the logging screen is within 9° of the ambient temperature.
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Halliburton Energy Services
07/97 770.00696-NW Troubleshooting 5-1
Troubleshooting
IntroductionThis section addresses the testing of a complete CAST-V electronics chassis assembly
(707.55595) or a DITS CAST modified to CAST-V by 707.55567.
Required Equipment• Digital voltmeter
• Dual trace storage oscilloscope
• PC with 1553 bus adapter card (3.35000)
• CAST-V monitor program - CMON.EXE (707.55634)
• Ground isolated variable voltage (0- to 120-Vac) supply
• 0- to 150-Vdc 1.5-A supply (Sorenson DCS 600-1.7 or equivalent)
• Dial-A-Source or equivalent reference dc supply
• DITS 37-pin jumper cable with breakout box
• Test transducer with fixturing (Figure 5-1)
• Sine wave oscillator, 300 to 500 kHz with 10-V p-p output level
• 50-Ω step attenuator, 3-dB steps to -60 dB
• AC voltmeter, HP 400 EL or equivalent
• Miscellaneous handtools
• Load box for testing power supply
• 5-Vdc load = 5 Ω
• +15-Vdc load = 50 Ω
• -15-Vdc load = 50 Ω• 400-Vdc load = 80.6 k Ω
• Jumper to intercept tool wiring to inverter board (refer to Figure 5-2 for jumper
wiring and parts list)
Recommended devices:
• HP355D provides 0 to 120 dB in 10-dB steps
• HP355C provides 0 to 12 dB in 1-dB steps
Section
5
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5-2 Troubleshooting 770.00696-NW 07/97
CAST-V TestingA test setup as shown in Figure 5-1 is recommended.
CAUTION Use the ground isolation transformer in the 120-Vac power circuit. If deleted, the chassis
will be 60-Vac above earth ground when powered up, possibly destroying the test
equipment and chassis components and delivering electrical shocks to personnel.
All the items illustrated in Figure 5-1 are not necessarily required until the final heat test.
A slightly different test setup is required (Figure 5-3) for testing the accuracy of the
amplifier chain in the signal path.
Figure 5-1: Bench Test Wiring Diagram
Resistance Tests
Perform the resistance checks provided in Appendix A, “Resistance Measurements.”
Correct all wiring errors indicated by the resistance measurements before proceeding.
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07/97 770.00696-NW Troubleshooting 5-3
Power Supply (Drawing 707.50606)
Inverter board 707.50602 and preregulator board 707.50605 work together to provide
+5-, ±15-, and +400-Vdc for the operation of the CAST-V electronics. During the
procedure refer to Figure 5-2, and schematics 707.50600 (Inverter - CAST Power
Supply) and 707.50603 (Preregulator - CAST Power Supply).
Figure 5-2: Block Diagram of the Cast-V Power Supply
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5-4 Troubleshooting 770.00696-NW 07/97
Setup Procedure
Remove screws, and loosen the boards from the chassis to provide easy access for
adjustments. The setup procedure requires that power be applied to the tool,
measurements be made at various places on the boards, FA resistors be set, and the
boards be reinstalled in the electronics chassis.
WARNING Do not operate the power supply with a short on any of the outputs.The input filter capacitor serving that output may overheat, swell,and possibly burst.
Note Determine the location of capacitors C9, C10, and C11 on the inverter board
before powering up the tool. If excessive operating current is detected (in excess of
250 mA at 120-Vac input), or if C9, C10, or C11 are self-heating, kill power
immediately (the self-heating is from excessive ripple current, not faulty parts).
Disconnect the tool electronics from the power supply by unplugging the connector from
J1. Connect the CAST load box (Figure 5-3) to connector Jl and the CAST-V wiring
harness to provide a load until power supplies are adjusted.
+15
R3 R5R4
R2
R1
J1-20J1-20
J1-19J1-19
J1-18J1-18
J1-17J1-17
J1-16J1-16
J1-15J1-15J1-14J1-14
J1-13J1-13
J1-12J1-12
J1-11J1-11
J1-10J1-10
J1-9J1-9
J1-8J1-8
J1-7J1-7
J1-6J1-6
J1-5J1-5
J1-4J1-4
J1-3J1-3
J1-2J1-2
J1-1J1-1 P2-1 P2-1
P2-2 P2-2
P2-3 P2-3
P2-4 P2-4
P2-5 P2-5
P2-6 P2-6
P2-7 P2-7
P2-8 P2-8
P2-9 P2-9
P2-10 P2-10
P2-11 P2-11
P2-12 P2-12
P2-13 P2-13
P2-14 P2-14P2-15 P2-15
P2-16 P2-16
P2-17 P2-17
P2-18 P2-18
P2-19 P2-19
P2-20 P2-20+400
+5
-15
PowerSupplyBoards
Tool
WiringHarness
COMPONENT PART NUMBER SOURCE
R1, R2 40 K VPR10F(40K) - ND DIGIKEYR3 5 OHMS VPR10F(5.0) - ND DIGIKEY
R4, R5 50 OHMS VPR10F(50) - ND DIGIKEYP2 .76909 HALLIBURTON
J1 .76900 HALLIBURTON
Figure 5-3: Load Resistances for Power Supply Testing
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07/97 770.00696-NW Troubleshooting 5-5
Power Supply Adjustment
Use the following steps to adjust the power supplies:
1. Apply power to the tool by turning up the variable transformer. Monitor the dc
voltage at the positive lead of C2 (chassis-mounted) as the variable transformer is
adjusted. Set the voltage to approximately 92-Vdc.
2. Use an oscilloscope to observe the waveforms at either end of R14 and R15 on theinverter board. A square wave should be present at each part. If the duty cycle is not
close to 50%, the current limiter (sense circuit across R16) may have problems.
3. Check the temperature on capacitors C9, C10, and C11 (just touch them lightly with
your finger). They should be cool. If any noticeable heating is occurring, then there
is an excessive current drain on the output filtered by that capacitor. If any self-
heating is evident, troubleshoot the short before proceeding.
4. Set the frequency of the square wave at R15 to between 18 and 20 kHz by adjusting
R7.
5. Check the waveform at the drains of Q2 and Q3. Each drain should show a square
wave of approximately 140 to190 V peak, with the negative edge at near ground
potential. The peak amplitude voltage becomes more predictable after setup is
complete.
6. On the preregulator board, connect a digital voltmeter to U1-8. Clip R-box across
R16, and adjust R16 to get exactly 10-Vdc at U1-8. Install a 1% RN55 resistor
(nearest value to the R-box reading) in the R34 position on the board. If zener CR11
voltage is near specification limit (>6.5-Vdc), R16 may be adjusted as well to get
exactly 10-Vdc out. If CR11 does not regulate between 6.15- to 6.78-Vdc, replace it.
7. Connect a voltmeter to the +5-Vdc output. A convenient point for this is the 5-V
turret terminals at the uphole end of the I beam part of the tool chassis. On the
preregulator board, connect the R-box across R12, and adjust to set voltage to
5 ±0.05 Vdc. Install a 1% RN55 resistor (nearest value to the R-box reading) in theR13 FA position on board.
8. Measure the voltage at the CR17 cathode (chassis-mounted zener). The voltage
should be 82 ±4 Vdc (not a specification, just a check of normal operation).
9. Vary the output voltage of the variable transformer from 100- to 140-Vac while
watching the +5-Vdc output level. The +5-Vdc output should change less than
0.05 V with any input voltage in the specified range.
10. Measure the voltage at the +15-Vdc output (the +15-V chassis terminal is
convenient). Voltage should be between +15- and +15.7-Vdc. This voltage is not
regulated with precision, and drops with increasing temperature.
11. Measure the voltage at the -15-Vdc output (the -15 V chassis terminal is convenient).Voltage should be between -15- and -15.7-Vdc. This voltage is not regulated with
precision and drops with increasing temperature.
12. Connect the voltmeter to the +400-V terminal on the chassis. Use the preregulator
board FA R27 (nominal 120 k Ω) to adjust the voltage to 400 ±4-Vdc.
Turn off the tool, remove the test load circuitry, and reconnect the power supply to the
chassis electronics.
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5-6 Troubleshooting 770.00696-NW 07/97
Parallel/Serial RTU-B Board (Drawing 3.85601)
Setup Procedure
1. Install termination resistor R1 according to the instructions on electronics chassis
assembly drawing 707.55595 (or 707.55567, if modifying a DITS CAST).
2. Configure board jumpers JMP1-JMP4 as follows:
• JMP1 — short pin 2 to pin 7
• JMP2 — unused
• JMP3 — short pin 1 to pin 14, short pin 3 to pin 12, short pin 6 to pin 9, short
pin 7 to pin 8
• JMP4 — short pin 1 to pin 8
3. Copy the CAST-V PC monitor program (CMON.EXE) into the PC to be used for
troubleshooting. From the DOS prompt, type “CMON.EXE” to run the program. The
main menu is displayed on the screen. For operating instructions, refer to
Appendix B, “CAST-V PC Monitor Program.”
4. Apply 120-Vac instrument power to the CAST-V electronics chassis.
5. From the main menu of the monitor program, type any key to begin the 1553
communication with the CAST-V.
Troubleshooting
1. If the monitor program displays error message “DITS ERROR 9,” the PC does not
recognize the 1553 bus adapter. Check for proper installation of the 1553 bus adapter
and proceed.
2. If the monitor program displays error message “DITS ERROR 8,” 1553 buscommunication with the CAST-V has not been established. Ensure that 120-Vac has
been applied to the tool. If 120-Vac is present, make sure that all tool dc power
supplies (+5, ±15, and +400 V) are functioning properly. If all supply voltages are
correct, then either the RTU-B board is bad, or something is wrong with the wiring
between the RTU-B and V40 CPU boards.
3. After 1553 communication has been established, there are no error messages and the
monitor program updates the screen with scan data.
Note Until the motor is spinning, the CAST-V does not update new scans, and the
monitor program only writes zeros to the screen.
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07/97 770.00696-NW Troubleshooting 5-7
R-to-D Board (Drawing 707.55561)
Setup Procedure
Apply 45 Vdc motor power to CAST-V electronics chassis. At this time, the scanner
head spins at around 5.0 rps. If the V40 CPU board is working, the motor speed is
echoed to the Mtr Speed parameter on the monitor screen. If the scanner head is notturning properly, then proceed to the following section “Troubleshooting.” Otherwise,
continue with board checkout.
1. Using an oscilloscope, make sure that the onboard oscillator at J2-4 (REFA) is
providing a sine wave of approximately 4-V p-p at 5 kHz. If the oscillator is set
properly, proceed to Step 2.
2. While the motor is spinning, monitor pins J2-5 (COS) and J2-7 (SIN). These signals
have an amplitude and phase that vary with the position of the motor armature. These
signals should be similar and should be sinusoidal in shape. If they are not, the
problem lies either in the wiring harness between the lower tool connector and the
board or within the scanner assembly. If the signals look good, go to Step 3.
3. With the scanner head spinning, monitor pins J1-8 (TACH/REF) and J1-15
(START). When the face of the transducer (mounted in the scanner head) passes
through the point on the tool housing corresponding to the DITS BUTTON, a +5-V
pulse occurs at J1-8. If the tool is in openhole mode, there are 200 pulses at J1-15 for
every pulse at J1-8. In cased-hole mode, there are 100 pulses at Jl-15 for every pulse
at J1-8.
Troubleshooting
1. If the scanner head is not spinning (or is cogging as it spins) and the current meter on
the dc power supply is excessively high (>1.0 A), then a transistor (FET) has
probably been blown on the commutator board. Turn off the dc motor power and
proceed to the section, “Commutator Board (Drawing 707.55559).”
2. If the scanner head is not spinning and the tool is not drawing any motor current
(supply current <5 mA), make sure that pin U4-12 has +5 V. If the voltage at this pin
is 0 V, then check for a bad EP310 (U4). If U4 is good, then the V40 CPU has not
properly initialized the R-to-D board. Proceed to the section, “V40 CPU Board
(Drawing 707.55666).”
Commutator Board (Drawing707.55559)
The following tests assume that a scanner with an adjusted resolver transformer isavailable. If the resolver transformer must be adjusted, use procedure 770.00103. The
scanner is used to provide a realistic test for the evaluation of the commutator board and
R-to-D board. If problems are encountered at any step, go to the following
“Troubleshooting” section.
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5-8 Troubleshooting 770.00696-NW 07/97
Setup Procedure
1. Turn OFF instrument power to the electronics chassis.
2. Slowly increase the motor power supply until 50-Vdc is reached while observing the
current meter on the Sorenson power supply. Current should be less than 0.005 A.
3. Set the Sorenson to 0-Vdc and turn on instrument power. The monitor program
begins 1553 communication with the tool.
4. Again turn up the Sorenson until the scanner motor begins revolving (probably at
less than 10-Vdc). Current drain from the Sorenson should be under 700 mA. If
current is acceptable, set the Sorenson to 50-Vdc.
5. Using a 10× probe on an oscilloscope, compare the waveform on the drains of Q3,
Q6, and Q9 on the commutator board with those provided in Figure 5-4, trace C.
(Figure 5-4, traces A and B, are gate drive waveforms provided for reference.)
6. Set the Sorenson to 45-Vdc. The monitor program screen indicates approximately
5.0 rps at Mtr Speed (screen updates for motor speed are slow). If the motor seems to
be rotating smoothly, motor current is normal, and the waveforms at the drains of
each FET pair are normal, proceed to the section, “V40 CPU Board (Drawing707.55666).”
Figure 5-4: Waveforms from Commutator Board FET Drains
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07/97 770.00696-NW Troubleshooting 5-9
Troubleshooting
Motor current should be nearly zero with no instrument power. If excessive current is
drawn with no instrument power applied, look for wiring errors first and then for blown
FETs.
For reference, Figure 5-4, trace C, is the drain waveform on an N-FET/P-FET pair.
Figure 5-4, trace A, is the drive waveform to a typical P-FET gate. When the P-FET gate
goes negative, the drain of the P-FET switches to near the supply voltage. Figure 5-4,
trace B, is the waveform for the N-FET gate. The N-FET switches its drain to near
ground whenever the Figure 5-4, trace B, waveform goes positive.
In practice, if the Sorenson current meter shows high current at low voltages, both the
P-FET and the N-FET in a pair may be blown, shorting the motor voltage directly to
ground.
Cogging, dead spots in the rotation, or roughness usually indicates only one blown FET.
The various components that drive the FETs rarely blow.
If the gate drive waveforms are not correct, check the wiring between R-to-D board and
commutator board. If the wiring is correct, ensure that the R-to-D board is generating
gate drive voltages (MOTR_A+, MOTR_A-, MOTR_B+, MOTR_B-, MOTR_C+, and
MOTR_C-) on schematic 707.55561.
V40 CPU Board (Drawing 707.55666)
Testing of the V40 CPU board requires that a scanner be connected to the chassis and
that motor power be applied to rotate the scanner. Ensure that 1553 communication has
been established between the PC and the CAST-V (no DITS errors on the monitor
screen).
Setup Procedure
1. With the scanner rotating, make sure that the Scan ID parameter is incrementing and
that it is a value from 0 to 255. If the scanner is rotating, but Scan ID reads zero, go
to Step 3 to determine if the problem lies with the V40 board or the acquisition
control and DSP board.
2. At 45-Vdc, the scanner rotates approximately 5.0 rps. This value is echoed to the
Mtr Speed parameter on the monitor screen.
Note Motor speed is a slow data channel therefore, it takes a few seconds for the new
motor speed to update to the screen.
3. Check the parameters in Table 5-1 to make sure that the V40 is correctly processingslow-channel data. If any of these parameters are incorrect, the V40 CPU Board is
probably bad. Otherwise, go to Step 4.
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Table 5-1: Parameters in the V40 CPU Slow-Channel Data Processing
Parameter Value Description
Tool Mode OPEN Default, openhole mode
Gate Start 30.0 Default, in µs
Casing OD 0 Default, in thousandths
Eff. Radius 0 Default, in thousandths
Wfm. Flag OFF Default
4. With the scanner head spinning, monitor the signal at pin J1-42 with a scope. This
signal is the interrupt to the V40 CPU indicating that a new scan has been acquired.
If there is no signal at this pin or if the frequency of the signal is not equal to one
pulse per scanner rotation, then check the wiring between the V40 CPU board and
the acquisition control and DSP board. Otherwise, there is a problem with the DSP
board.
Slow ADC Board (Drawing 707.55587)
The slow ADC board assembly is mounted at the bottom of the electronics chassis
assembly. Many of the voltages measured by the slow ADC come from the directional
sub through connector P1 on the chassis assembly. The input connections to the slow
ADC are accessed through the breakout box in the 37-pin DITS jumper shown in
Figure 5-1.
The following procedure tests all major board functions. Note that INCL and MAG
readings update rapidly and that Motor V, Motor I, and Temp updates are slower. The
scanner does not have to be rotating for the first of these tests and will only be powered
up for the Motor V and Motor I tests.
Setup Procedure
1. Visually inspect the slow ADC Assembly to ensure that the jumper from J2-3 to
J2-12 is in place.
2. Connect the voltage reference source (Dial-A-Source or equivalent) to the bottom
tool connector, as shown in Figure 5-1.
3. Switch the voltage reference to the inputs as indicated in Table 5-2. At each point,
the monitor program indicates the reference voltage input within the tolerances
indicated in the table. Check each input with positive input voltages first. Then
repeat the test with negative input voltages.
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Table 5-2: Slow ADC Voltage Reference
Input Voltage Input Voltage Read
INCLX ±4.00 ±3.98 to 4.02
INCLY ±4.00 ±3.98 to 4.02
MAGX ±4.00 ±3.98 to 4.02
MAGY ±4.00 ±3.98 to 4.02
INCLX ±0.05 ±0.046 to 0.054
INCLY ±0.05 ±0.046 to 0.054
MAGX ±0.05 ±0.046 to 0.054
MAGF ±0.05 ±0.046 to 0.054
4. Connect Dial-A-Source to TEMP lead and set to 1.55-Vdc. The monitor program
reading of Temp should be 100 ±3°C.
5. Set the Sorenson to 50-Vdc. The scanner begins revolving. The monitor programindicates 50- ±2-Vdc at Motor V. The current meter of the Sorenson shows the same
current as is indicated at Motor I ±5%.
Troubleshooting
If the monitor program is not updating new readings from the slow ADC, make sure that
connector P30 is secured to the V40 CPU board at connector J2. If it is, then check for
strobes from the V40 serial port at pin J1-13. If there are not any strobes, the problem is
either the V40 CPU board or the wiring between the slow ADC and V40 CPU boards.
Preamplifier/Fire Board (707.55668)
The transducer setup shown in Figure 5-5 is used to provide realistic signals for test
purposes. Insulate the transducer wires from the water in the bucket. Transducer wires of
2 ft or less are desirable. Transducer wires of up to 6 ft can be used, but longer leads
should be of shielded wire or twisted pair. Lead polarity is not important. The important
aspects of the test setup are:
• repeatable known spacing from transducer to target
• parallel spacing between the face of the transducer and the target
• known thickness of the target
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0.300
TARGET
TESTTRANSDUC
1.50
1.50
2.00
Figure 5-5: Stand Test Target Setup (distances in in.)
Connections from the test transducer to the tool are made with clip leads or solder
connections to preamplifier/fire board terminals TP-4 (connected in parallel to J1/P21) or
TP-5 (connected in parallel to J2/P20). Coax connectors P20 and P21 are unplugged
when using the test transducer. Do not connect the test transducer in parallel with the
scanner transducer during testing. Finally, do not make or break connections to the
transducer while the firing circuit is operating. Shorts to ground at the preamplifier/fire
board transducer connections blow the FETs generating the fire pulse.
Setup Procedure
Use the following steps to test the preamplifier/fire board. If problems are encountered at
any step, proceed to the “Troubleshooting” section.
1. Turn power OFF to the motor and electronics chassis assembly.
2. Connect the test transducer to TP-5. Disconnect the coax cable from connector J2.
3. Apply instrument power to the electronics chassis assembly. Apply motor power to
the chassis (30-Vdc is enough). Confirm rotation of the scanner head.
4. Monitor test point TP-2 (FIRE). A +5-Vdc pulse at this pin begins the firing process.
5. Using a 10× probe, examine the waveform at TP-5. The waveform should be similar
to that shown in Figure 5-6. If the waveform is similar, turn off instrument power,
disconnect the test transducer, and reconnect the coax cable from the scanner to J2.
6. Connect the test transducer to TP-4. Disconnect the coax cable from J1. Apply power
to the tool. Confirm rotation of the scanner head.
7. Connect an oscilloscope to TP-1. Positive 5-Vdc pulses should be visible, but occur
less frequently than on TP-2. The pulses at this point occur when the mud-cell firing
circuit is enabled.
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8. Using a 10× probe, examine the fire-pulse waveform at TP-4. The waveform should
be similar to that shown in Figure 5-6. (The fire-pulse at TP-4 occurs infrequently,
and is easiest seen using a storage or digital oscilloscope.) If the pulse at TP-4 is
similar to Figure 5-6, turn off instrument power, disconnect the transducer from
TP-4, and reconnect the coax cable to J1.
Testing of amplifier gains on the preamplifier/fire board is done at a later stage (gain
range testing).
Figure 5-6: Fire-Pulse Waveform
Troubleshooting
If there are no pulses at TP-2, make sure that there is activity on pins J5-20 (TACH/REF)and JS-36 (START) of the acquisition control and DSP board. If not, there is either a
wiring problem between the DSP board and the R-to-D board or there is a problem with
the R-to-D board. However, if there is activity on these pins, check for pulses at J5-47
(FIRE) on the DSP board. If there are no pulses, something is wrong with the DSP
board. Correct the DSP board problem and continue with preamplifier/fire board
checkout.
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Data Acquisition Board (Drawing 707.41002)
Setup Procedure
1. Connect the digital voltmeter to the positive lead of C29. Adjust measured voltage to
4.00 ±0.02-Vdc using FA resistor R31 (nominal 85 k Ω).
2. Ensure that the scanner head is spinning and that the measurement transducer is
firing properly within its test fixture. Using a scope probe, monitor pin U10-28. This
is the input to the 8-bit ADC (MP7684).
3. Refer to Appendix B for the following discussion. If the Tool Mode parameter on the
PC monitor screen is set to OPEN, then the tool is in openhole mode and the signal
at U10-28 (as seen on the oscilloscope) looks similar to Figure B-2 (Appendix B).
The transit times are not the same because the target distances are different, but the
signal character is similar. If there is no acoustic signal or if the waveform does not
look right, proceed to “Troubleshooting.” Otherwise, go to Step 4.
4. Switch into waveform mode by typing . The Wfm. Flag parameter should be ON.
If the waveform on the lower portion of the monitor screen looks similar to thewaveform in Figure B-2, then the digitized waveform is transferred properly from the
data acquisition board to the acquisition control and DSP board. If not, proceed to
“Troubleshooting.” Otherwise, disable waveform mode (by typing ), and go to
Step 5.
5. Switch to cased-hole mode by typing and entering . If the Tool Mode parameter
is set to CASED, then the tool is in cased-hole mode and the signal at U10-28 (as
seen on the oscilloscope) looks similar to Figure B-3. If there is no acoustic signal or
if the waveform does not look right, proceed to “Troubleshooting.” Otherwise, go to
Step 6.
6. Switch to waveform mode by typing . The Wfm. Flag parameter should be ON. If
the waveform on the lower portion of the monitor screen looks similar to the
waveform in Figure B-3, then disable waveform mode (by typing), and proceed to
the section :Acquisition Control and DSP Board (Drawing 707.55665).” However, if
the waveforms are not similar, go to “Troubleshooting.”
Troubleshooting
Disconnect coax connector P17 from the data acquisition board. Check connector P18 on
the preamplifier/fire board for acoustic signal. If there is no signal, the problem lies in
the preamplifier/fire board. Otherwise, the problem lies either in the data acquisition
board or in the wiring between the preamplifier/fire and data acquisition boards.
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Acquisition Control and DSP Board (Drawing 707.55665)
To successfully reach this point in the test procedure, most of the electronics and
firmware on the acquisition control and DSP board must be working properly. The
amplitude and transit time values need to be checked to guarantee a good measurement.
Setup Procedure1. Ensure that the scanner head is spinning and that the measurement transducer is
firing properly within its test fixture.
2. Refer to Appendix B during the following discussion. Make sure that the tool is in
openhole mode by typing and entering . When the Tool Mode parameter is set to
OPEN, switch to waveform mode by typing. If the waveform on the lower portion
of the monitor screen is similar to the waveform in Figure B-2, then the DSP
firmware is gain-ranging the acoustic signal.
3. A crosshair is displayed on the monitor screen at the location of the transit time pick.
This crosshair coincides with the onset of the reflected acoustic signal. If the
crosshair is moving around by more than four or five samples, then check forexcessive baseline noise (>30 mV) caused by the analog electronics. Correct the
noise problem, and go to Step 4.
Note The transit time pick MUST be stable to guarantee a good log. Otherwise, the
DSP firmware is not consistently picking on the same portion of the waveform.
4. Disable waveform mode (by typing ), and note the transit time value for the first
shot of scan data (refer to Appendix B, Figure B-4). This value is displayed in
hexadecimal format and must be converted to decimal counts. Convert a transit time
value from counts to actual time units (µs) using the following equation.
Transit time counts × 0.2 µs/ count = transit time
The calculated transit time value for the first shot of scan data is echoed to the Shot 1 DT
parameter on the monitor screen. Using the Figure 5-5 test setup as an example, transit
time is 255 counts.
255 counts × 0.2 µs/ count = 51 µs
A transmit time of 51 µs should be echoed at Shot 1 DT. The speed of sound in water
(for round trip travel) is approximately 34 µs/in. Therefore,
51
inin.
µ
µ
s
s3415
/ ..=
A distance of 1.5 in. is consistent with the distance from the transducer to the test target.
5. Switch the tool to cased-hole mode by typing and entering . When the Tool Mode
parameter is set to CASED, switch to waveform mode by typing . If the waveform
on the lower portion of the monitor screen is similar to the waveform in Figure B-3,
then the DSP firmware is gain-ranging the acoustic signal.
6. Disable waveform mode by typing . Note the transit time value for the first shot of
scan data as in Figure B-5 (Appendix B). This value is identical to the transit time
pick for the openhole mode.
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Gain-Range Testing
The following procedure tests the gain-ranging function of the acquisition electronics.
The amplifier stages can be found on the preamplifier/fire and data acquisition boards.
The switching of amplifiers is controlled by the acquisition control and DSP board.
Use the test setup in Figure 5-7 for the gain-range tests.
If a 10-dB/step attenuator is used with a 1-dB/step attenuator to get the necessary 3-dBsteps, connect the two attenuators in series.
The procedure includes a complete test of the scanner transducer channel. The mud-cell
channel is only tested at two input levels, and the levels are chosen to test the
components on the preamplifier/fire board not common to the scanner transducer.
Test Procedure
1. With instrument power disconnected, connect the apparatus as shown in Figure 5-7.
Connect the attenuator output to TP-5 on the preamplifier/fire board with the J2 coax
disconnected. Connect the attenuator ground near the preamplifier/fire board.
2. Remove FET driver chip U4 (D469A) from the preamplifier/fire board.
3. Apply instrument and motor power (30-Vdc) to the CAST-V electronics chassis. The
scanner is rotating.
4. From the main menu of the monitor program, type any key to begin the 1553
communication with the CAST-V.
5. Observe the Shot 1 Pk parameter on the monitor screen. Set the generator to 500
kHz. Set the attenuator to 0 dB, and adjust the signal generator until Shot 1 Pk reads
“4.0XXX volts,” where X reflects a “doesn't care” status.
6. Increase attenuation in -3-dB steps (decreasing signal amplitude), and take readings
from Shot 1 Pk on the monitor screen. Enter the values in Table 5-3 and compare thevalues to tolerance limits. When a -10-dB step is required, always set the 1-dB
attenuator first.
Example: When changing from -12 to -15 dB, first change the 1-dB attenuator from -12
to -5 dB. Then, increase the 10-dB attenuator from 0 to -10 dB.
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07/97 770.00696-NW Troubleshooting 5-17
SINE WAVESIGNAL
GENERATOR50 OHM
50 OHMATTENUATOR
ACVOLT METER
AC INSTRUMENTPOWER SOURCE
PREAMP / FIREBOARD
PERSONALCOMPUTER WITHDITS CARD ANDMONITOR PROG.
TP5
TP4
J2
J1
D469
HYBRID
Figure 5-7: Gain Test Setup
7. Set the attenuator to provide 60 dB of attenuation. Decrease attenuation in 3-dB steps
(increasing signal amplitude) and take readings from Shot 1 Pk on the monitor
screen. Enter the Shot 1 Pk values in Table 5-4.
8. Turn OFF tool power. Disconnect the generator from TP-4. Reconnect the coax to
J2.
9. Disconnect the coax from J1. Connect the attenuator output to TP-5. Apply
instrument and motor power. The test setup is now connected to test the mud-cell.
(The update rate on the mud-cell is slower than on the scanner transducer, but only
two points need to be checked.)
10. Set the attenuator to 0-dB attenuation (Do not recalibrate generator output. Use the
same output level as in Step 5). Enter the Mud Pk voltage in Table 5-5.
11. Set the attenuator to -60 dB. Enter the Mud Pk voltage in Table 5-5.
12. Turn OFF power and disconnect the attenuator from the preamplifier/fire board.
Reconnect the coax to connector J1.
13. Check all readings against the limits provided in Tables 5-3 through 5-5. If all
readings are within limits, gain testing is complete. Reinstall D469 into the U4
socket.
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Table 5-3: Gain Test, Increasing Attenuation and Decreasing Amplitude
Step Gain (dB)
Nominal Peak V
Minimum Peak V
Maximum Peak V
Shot 1 Pk Voltage
0 0 4.0000 4.0000 4.0000
1 -3 2.8284 2.5456 3.1113
2 -6 2.0000 1.8000 2.20003 -9 1.4142 1.2728 1.5556
4 -12 1.0000 0.9000 1.1000
5 -15 0.7071 0.6364 0.7778
6 -18 0.5000 0.4500 0.5500
7 -21 0.3536 0.3182 0.3889
8 -24 0.2500 0.2250 0.2750
9 -27 0.1768 0.1591 0.1945
10 -30 0.1250 0.1125 0.1375
11 -33 0.0884 0.0795 0.0972
Table 5-4: Gain Test, Decreasing Attenuation and Increasing Amplitude
Step Gain (dB)
Nominal Peak V
Minimum Peak V
Maximum Peak V
Shot 1 Pk Voltage
12 -60 0.0039 0.0035 0.0043
13 -57 0.0055 0.0050 0.0061
14 -54 0.0078 0.0070 0.0086
15 -51 0.0110 0.0099 0.0122
16 -48 0.0156 0.0141 0.017217 -45 0.0221 0.0199 0.0243
18 -42 0.0313 0.0281 0.0344
19 -39 0.0442 0.0398 0.0486
20 -36 0.0625 0.0563 0.0688
21 -33 0.0884 0.0795 0.0972
22 -30 0.1250 0.1125 0.1375
23 -27 0.1768 0.1591 0.1945
Table 5-5: Gain Test, Mud-Cell Channel
Attenuator Setting
Nominal Peak V
Minimum Peak V
Maximum Peak V
Mud Pk Voltage
0 dB 4.0000 3.5000 4.3000
-60 dB 0.0039 0.0035 0.0043
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07/97 770.00696-NW Troubleshooting 5-19
Heat Test and QC Data Collection
Collection of data for QC files and heat testing requires that the electronics chassis
assembly be placed in a Dispatch oven, while connected as shown in Figure 5-8. After
confirming correct tool function, ambient data readings for both cased-hole and openhole
mode are entered into the form provided. The chassis assembly is then heated to 350°F
and soaked for 1 hour, and elevated temperature readings are entered into the form
provided. Data are then evaluated, and a final inspection is given to the tool.
Procedure
1. Place the electronics chassis assembly in the Dispatch oven. Sleeve the chassis
assembly, or place it in the oven to prevent hot spots on the tool chassis. Connect a
thermocouple digital temperature gage to the chassis.
2. Collect data to fill the “Ambient” columns on the data sheet provided.
3. Heat the oven to 350°F, and hold for 1 hour.
4. Collect data to fill the “350°F” columns on the data sheet provided.
5. Compare all readings to ensure that temperature drift is within the limits provided.
6. Terminate the oven test, and allow the chassis to cool to ambient temperature.
7. Carefully inspect the tool for heat-induced damage. (Be sure to check the capacitors
in the power supply for signs of swelling or leakage.)
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CAST-V HEAT TEST DATA
TOOL SERIAL No.
Variable Ambient Cased-
Hole
Ambient Open Hole
350 ° F Cased-Hole
350 ° F Openhole
Normal Tolerance
Shot 1 DT
(µs)
±1 µs
Shot 1 Pk
(V)±10%
Motor V
(V)
±10%
Motor I
(A)±10%
Scan ID
Counting?
Yes/No
Mud DT ±10%
+5-Vdc ±100 mV
+15-Vdc +0/-1-Vdc
-15-Vdc -0/+1-VdcINCLY
1Good/Bad
400-Vdc ±10-Vdc
1 If the directional sub is connected in the test setup, rotate the sub to get the INCLY
reading to near 0-Vdc out. Record voltages, but only look for an obvious failure.
ATTACHMENTS:
1. Screen prints of cased-hole and openhole waveforms taken at ambient temperature.
2. Screen prints of cased-hole and openhole waveforms taken at 350°F.
TECHNICIAN NAME DATE OF TEST
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07/97 770.00696-NW Troubleshooting 5-21
Dial-A-SourceVoltage ReferenceBreak-out
Box
ClipLead 0 to 150 vdc at 1.5 amp
Sorenson Power Supply
Dispatch oven containingelectronics chassis Assembly
Isolated ACpower source
Transducer in
water-filledtest fixture
Personal computer withDits Exerciser card
installed
Directional sub(optional)
ScannerMud cell pointed upand filled with water
Figure 5-8: Oven Test Setup
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Halliburton Energy Services
07/97 770.00696-NW References 6-1
References
IntroductionThis section contains reference material and information about the DITS CAST tool
upgrade to the CAST-V.
ManualsThe following manuals are available as references for the CAST-V:
• CAST-V Field Operations Manual - Image Mode, 770.00700
• CAST-V Field Operations Manual – Cased Hole, 770.00709
• CAST-V Engineering Documentation Package, 770.00710
DITS CAST Tool Upgrade to the CAST-VDITS CAST tools upgraded to the CAST-V configuration require power supply board
assembly, 707.50606, to be modified. This procedure explains how to modify the DITS
CAST power supply to obtain the higher output voltages required by CAST-V. The
higher output voltages are necessary to ensure proper operation of the motor drive
circuitry at elevated temperatures.
Reference Drawings• DITS CAST to CAST-V Electronics Chassis Modification, 707.55567
• Power Supply PC Board Assembly, 707.50606
• Toroid Transformer, 707.50607
• Inverter PC Board Assembly, 707.50602
• Preregulator PC Board Assembly, 707.50605
Section
6
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6-2 References 770.00696-NW 07/97
General Information
CAST-V tools use a toroid transformer, P/N 707.50607, revision B, that has a different
winding structure than the toroid transformer previously used on DITS CAST tools. The
DITS CAST toroid transformer, P/N 707.50607, revision NW, must be replaced with a
revision B transformer or modified by adding additional windings to the existing
transformer. Additional changes to the power supply circuitry are necessary to
compensate for replacement or modification of the transformer. After completion of thisprocedure the output of the ±15-Vdc increases from 14.5- to 15.5-Vdc.
Transformer Identification
The vendor identifies toroid transformer 707.50607 by serial numbers as follows:
• revision NW is serial numbers 001 through 045
• revision A was never manufactured
• revision B is serial numbers 046 and up
Upgrade Procedure
1. Remove the power supply board assembly from the electronics chassis, and locate
the toroid transformer 707.50607 on inverter board 707.50602.
2. Remove the nut and washer from the mounting screw retaining the transformer to
the PC board. Unthread the screw from the Teflon cone, and remove it from the
board. Save all hardware.
3. Carefully remove the transformer from the PC board, and remove as much RTV as
possible without damaging the transformer.
Note If transformer 707.50607, revision NW, is now replaced with 707.50607, revisionB, then proceed directly to Step 6.
4. Using 24 AWG Teflon insulated wire (P/N .83489), make two windings, each with
one turn (see Figure 6-1). It is not necessary to tape the new windings to the core.
When mounted to the board, the transformer mounting cone and RTV adequately
secure the wire windings. The added windings also do not overlap where the
mounting cone could crush the insulation and short the wires.
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07/97 770.00696-NW References 6-3
Note:"One turn" on a toroid requires that the wire pass through the center hole of the toroid only once.
Positioning of the wire around the toroid perimeter is not important.
Figure 6 -1: Toroid Winding
5. Referring to Figure 6-2, make the added turn connections. If connected correctly, the
voltage from the added turns add to the voltage from W5 and W6 on transformer
707.50607. The peak-to-peak voltage at turret 4 is 2 V higher than the peak-to-peak
voltage at the junction of the added turn at WHT/RED. Similarly the peak-to-peak
voltage at terminal 8 will be 2 V higher than the peak-to-peak voltage at the added
turn at WHT. The ±15-Vdc outputs each increase to approximately 15.5-Vdc.
6. Reattach the transformer to the PC board using the original hardware.
7. Replace resistors R20, R21, and R32, located on preregulator board 707.50605, as
indicated below.
• R20. Replace P/N .73379 (15K, 3W) with P/N .02168 (10K, 3W).
• R21. Replace P/N .73379 (15K, 3W) with P/N .02168 (10k, 3W).
• R32. Replace P/N .73608 (5K, 3W) with P/N .25193 (6.2K 3W).
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6 -4
R ef er en c e
s
7 7
0 . 0 0 6 9 6 -NW
0 7 / 9 7
F i g ur e 6 -2 : Wi r i n g of M o d i f i e d T
r an sf or m er
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Halliburton Energy Services
07/97 770.00696-NW Resistance Measurements A-1
Resistance Measurements
IntroductionThis appendix provides preventive maintenance (PM) measurement criteria for the
CAST-V electronics chassis.
Downhole End Resistance Measurements
Table A -1: Downhole End Resistance Measurements
From To Read Scale Items Checked
(Note 1) (Note 2)
1 Chassis Short RX1 Ground for scanner transducer
2(±) Chassis 2.4-2.7 k Ω RX100 Scanner Xducer signal (slight diode
effect)
3(±) Chassis >4 k Ω Rx100 Slow ADC ID input
4 - 6 Chassis Short RX1 Chassis ground connection
7(±) Chassis 2.4-2.7 k Ω RX100 Mud transducer signal (slight diode effect)
8 Chassis Short RX1 Chassis ground connection
9 Chassis Short RX1 Ground for mud transducer
10 Chassis Short RX1 Chassis ground connection
11 Chassis Short RX1 Chassis ground connection
12 - 13 N.C.
14(+) Chassis 15-20 k Ω RX100 Resolver sine (diode effect)
14(-) Chassis 7.5-10 k Ω RX100 Resolver sine (diode effect)
15(+) Chassis 15-20 k Ω RX100 Resolver cosine (diode effect)
15(-) Chassis 6-8 k Ω RX100 Resolver cosine (diode effect)
16(+) Chassis 50-120 RX1 5-Vdc power (large diode effect)
16(-) Chassis <10 RX1 5-Vdc power (large diode effect)
17(+) Chassis 2600 RX100 +15-Vdc power (large diode effect)
17(-) Chassis 470 RX100 +15-Vdc power (large diode effect)
Appendix
A
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A-2 Resistance Measurements 770.00696-NW 07/97
Table A-1: Downhole End Resistance Measurements (concluded)
From To Read Scale Items Checked
(Note 1) (Note 2)
18(+) Chassis 480 RX100 -15-Vdc power (large diode effect)
18(-) Chassis 2200 RX100 -15-Vdc power (large diode effect)
19 N.C.
20 Chassis Short RX1 Resolver shield21(±) Chassis 2.5-6 k Ω RX100 Ref A - Res. Drv. Signal (slight diode
effect)
22 Chassis Short RX1 Resolver Gnd
23 N.C.
24 Chassis 70-90 k Ω RX10K Input to slow ADC
25 Chassis 70-90 k Ω RX10K Input to slow ADC
26 Chassis 70-90 k Ω RX10K Input to slow ADC
27 Chassis 70-90 k Ω RX10K Input to slow ADC
28 Chassis 70-90 k Ω RX10K Input to slow ADC
29 Chassis Short RX1 Chassis ground connection
30-34 N.C.35 (-) Chassis <10 RX1 FET body diode in commutator bd. Q2
36 (-) Chassis <10 RX1 FET body diode in commutator bd. Q5
37 (-) Chassis <10 RX1 FET body diode in commutator bd. Q8
35 (+) Chassis >3000 RX100 FET body diode in commutator bd. Q2
36 (+) Chassis >3000 RX100 FET body diode in commutator bd. Q5
37 (+) Chassis >3000 RX100 FET body diode in commutator bd. Q8
35 (+) Pin 13
Uphole
<100 RX1 FET body diode in commutator bd. Q3
36 (+) Pin 13
Uphole
<100 RX1 FET body diode in commutator bd. Q6
37 (+) Pin 13Uphole
<100 RX1 FET body diode in commutator bd. Q9
35 (-) Pin 13
Uphole
>3000 RX100 FET body diode in commutator bd. Q3
36 (-) Pin 13
Uphole
>3000 RX100 FET body diode in commutator bd. Q6
37 (-) Pin 13
Uphole
>3000 RX100 FET body diode in commutator bd. Q9
NOTE 1: The sign in parentheses indicates polarity of meter lead connected to test point.
NOTE 2: All readings taken with a Simpson 260. Different brands of meters show different
resistances in checking nonlinear circuits, that is, circuits with diodes present.
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07/97 770.00696-NW Resistance Measurements A-3
Uphole End Resistance Measurements
Table A -2: Uphole End Resistance Measurements
From To Read Scale Items Checked
(Note 1) (Note 2)
1 2 55 RX1 DITS transformer and line resistors3 N.C.
4 Chassis Open (DITS shield)
5 - 12 N.C.
13 14 5 - 7 RX1 Power transformer continuity
13 (-) Chassis 10-30 RX1 Mot. switching FET body diodes turned on
13 (+) Chassis 1.5-2.0 k Ω RX100 Mot. switching FETs turned off. (large
capacitor charge time)
14 (-) Chassis 10-30 RX1 Mot. switching FET body diodes turned on
14 (+) Chassis 1.5-2.0 k Ω RX100 Mot. Switching FETs turned off. (large
capacitor charge time)
15 N.C.16 19 5 - 7 RX1 Power transformer continuity
16 Chassis 3 - 5 RX1 Auxiliary power connection to chassis
17 N.C.
18 N.C.
19 Chassis 3 - 5 RX1 Auxiliary power connection to chassis
NOTE 1: The sign in parentheses indicates polarity of meter lead connected to test point.
NOTE 2: All readings taken with a Simpson 260. Different brands of meters show different
resistances in checking nonlinear circuits, that is, circuits with diodes present.
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Halliburton Energy Services
07/97 770.00696-NW CAST-V PC Monitor Program B-1
CAST-V PC Monitor Program
IntroductionThis C language program serves as a mechanism for sending tool commands and
monitoring tool data without a surface system. The communication scheme between the
CAST-V and the PC is 1553 Manchester.
Required Equipment• 386 or higher microprocessor
• VGA or higher monitor
• 1553 bus adapter 3.35000
• CAST-V PC Monitor Program - CMON.EXE (707.55634)
OperationTable B-1 describes the tool commands available to the user (refer to Figure B-1).
Table B-1: Tool Commands of the CAST-V PC Monitor Program
Command Description
Switches tool modes in the CAST-V. Select OPEN for openhole mode
and CASED for cased-hole mode. The tool echoes its current mode of
operation to the Tool Mode parameter on the monitor display.
Toggles the CAST-V between sending scan data and waveform data.
When the tool is sending scan data (default), the Wfm. Flag is OFF, and
scan data is displayed on the lower portion of the screen. When the tool
is sending waveform data, the Wfm. Flag is ON, and 128 µs of
waveform is displayed on the lower portion of the screen.
Defines the start point of the scan data display. This number is the offset
in words into the scan data from the fire-pulse.
Appendix
B
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B-2 CAST-V PC Monitor Program 770.00696-NW 07/97
Table B-1: Tool Commands of the CAST-V PC Monitor Program (concluded)
Command Description
Sets the start position in counts1 of the gating function in the acquisition
electronics. All digital processing on the transducer signal begins at this
location in the waveform.
Sends the casing OD in thousandths of an inch, to the CAST-V for use
by the thickness algorithm. The casing OD is echoed to the Casing OD
parameter on the monitor display.
Sends the effective tool radius in thousandths of an inch, to the CAST-V
for use by the thickness algorithm. The effective tool radius is echoed to
the Eff. Radius parameter on the monitor display.
Pauses the display and the 1553 communication with the CAST-V.
or Help. Displays the help command menu.
Quit.
1 1 Count = 0.2 µs
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07/97 770.00696-NW CAST-V PC Monitor Program B-3
CAST-V PC Monitor Program (707.55634 -.NW)
Commands:
m
t
s
g
ce
Spacebarh,?
q
Set Tool Operating Mode (OPEN/CLOSED)
Toggle Waveform Display Mode (ON/OFF)
Set Data Display Start Point
Set Gate Start Position
Set Casing OD
Set Effective Tool Radius
Pause displayHelp. Display this Menu.
Quit
Refer to CAST-V Electronics Assy Test Procedure (770.10511) for detailedoperating instructions.
TYPE ANY KEY TO CONITINUE
Figure B-1: PC Monitor Program Main Menu
After a command is sent to the tool, the command information is echoed to the bottom of
the monitor display in the following format (refer to Figure B-2):
Command sent- X Y,
where:
X is the command sent to the tool in hexadecimal format
Y is the corresponding data in decimal format.
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B-4 CAST-V PC Monitor Program 770.00696-NW 07/97
Scan ID
Mtr Speed (rps)
Tool Mode
Gate Start (us)
Casing O.D.
Eff. RadiusVersion
Wfm. Flag
163
5.1
OPEN
30.0
0
0C
ON
INCLX (V)
INCLY (V)
MAGX (V)
MAGY (V)
Motor V (V)
Motor I (A)Temp (Deg C)
-3.156
-3.210
-1.883
-2.704
0.277
-0.006-1566.258
Mud Pk
Mud Pk Gain
Mud DT (us)
Mud Sum
Mud Sum Gain
Mud Target TkAzimuth (Deg)
Wfm. DT (us)
0
0
0.0
0
0
0235.1
53.8
Command sent- F6 150
10 us./div.
COMMAND ECHO
PEAK AMPLITUDE
TRANSIT TIME PICK
Figure B-2: Waveform Data for Openhole Mode
Interpretation:
Critical tool parameters are displayed in the top portion of the monitor display.
Table B-2 describes each parameter.
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07/97 770.00696-NW CAST-V PC Monitor Program B-5
Table B-2: Tool Parameters of the CAST-V PC Monitor Program
Parameter Description
Scan ID Number of current scan. An incrementing Scan ID value (0 to 255) is
an indication that the 1553 communication is still active and that the
CAST-V is updating new scan data to the surface.
Mtr Speed Speed in rps of the spinning scanner head. This value is useful in
determining whether or not the head is rotating at the correct speed.
In cased-hole mode, this value should not exceed 10.0 rps (downhole
processing limitation). In openhole mode, this value should not
exceed 15.0 rps (telemetry limitation).
Tool Mode Current operating mode (OPEN/CASED). OPEN (default) indicates
that the tool is in the openhole mode. CASED indicates that the tool
is in the cased-hole mode.
Gate Start Start position of the gate in µs for the digital processing of the
transducer signal.
Casing OD Outside diameter of the casing. This parameter is needed by theCAST-V firmware as input to its thickness algorithm. The casing OD
in thousandths of an inch, is echoed from the tool to this screen
location.
Eff. Radius Effective spinning radius of the transducer from the centerline of the
tool housing. This parameter is needed by the CAST-V firmware as
input to its thickness algorithm. The effective radius in thousandths
of an inch, is echoed from the tool to this screen location.
Version Current number of the CAST-V firmware.
Wfm. Flag Waveform mode flag. This parameter is ON when the waveform
mode is enabled and OFF when waveform mode is disabled.
INCLX Raw voltage measured by the slow ADC board of output from the x-
coordinate of the inclinometer.
INCLY Raw voltage measured by the slow ADC board of output from the y-
coordinate of the inclinometer.
MAGX Raw voltage measured by the slow ADC board of output from the x-
coordinate of the magnetometer.
MAGY Raw voltage measured by the slow ADC board of output from the y-
coordinate of the magnetometer.
Motor V DC voltage supplied to the commutator board. This value is echoedfrom the tool and differs from the Sorensen voltage meters whenever
cable resistance is present.
Motor I DC current drawn by the scanner motor. This value is echoed from
the tool and should be equivalent to the value seen at the Sorensen
supply within a few mA.
Temp Temperature in °C within the directional sub housing.
Table B-2: Tool Parameters of the CAST-V PC Monitor Program (concluded)
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B-6 CAST-V PC Monitor Program 770.00696-NW 07/97
Parameter Description
Shot 1 Pk Gain-recovered amplitude in volts for the first shot of scan data. This
is the amplitude of the signal measured at the transducer. This value
is not displayed in waveform mode.
Mud Pk Gain-recovered amplitude (in volts) for the mud cell. This is the
amplitude of the signal measured at the transducer. This value is notdisplayed in waveform mode.
Mud Pk Gain System gain in 3-dB steps for the peak window of the mud-cell
transducer.
Mud DT Delta-T (or transit time) pick for the mud-cell transducer. Distance
from the mud-cell to the target is approximately 1.25 in.
Mud Sum Sum value within the resonance window of the mud-cell transducer.
This value is not gain recovered.
Mud Sum Gain System gain in 3-dB steps for the resonance window of the mud-cell
transducer.
Mud Target Measured thickness in thousandths of an inch, of the mud-cell target.
The mud-cell target is 0.3 in. thick.
Azimuth Clockwise angle in degrees from the DITS button to magnetic north.
This value is calculated from the raw voltages of MAGX and
MAGY.
Shot 1 DT Transit time in µs for the first shot of scan data. This value is not
displayed in waveform mode.
Wfm. DT Transit time in µs of the acquired waveform. This value is only
displayed in waveform mode.
In waveform mode Wfm. Flag is ON, 128 µs of waveform are displayed on the lowerportion of the monitor screen. Mud-cell information is not updated in waveform mode.
Examples of openhole and cased-hole waveforms can be found in Figures B-2 and B-3,
respectively.
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07/97 770.00696-NW CAST-V PC Monitor Program B-7
Scan ID
Mtr Speed (rps)
Tool Mode
Gate Start (us)
Casing O.D.
Eff. RadiusVersion
Wfm. Flag
196
4.9
CASED
30.0
0
0C
ON
INCLX (V)
INCLY (V)
MAGX (V)
MAGY (V)
Motor V (V)
Motor I (A)Temp (Deg C)
-1.614
-1.642
-1.271
-1.550
0.207
-0.006-1041.214
Mud Pk
Mud Pk Gain
Mud DT (us)
Mud Sum
Mud Sum Gain
Mud Target TkAzimuth (Deg)
Wfm. DT (us)
0
0
0.0
0
0
0230.6
54.0
10 us./div.
PEAK AMPLITUDE
12.8 Secµ
RESONANCEWINDOW
TRANSIT TIME PICK
Figure B-3: Waveform Data for Cased-Hole Mode
When the waveform mode is disabled Wfm. Flag is OFF, scan data are displayed on the
lower portion of the monitor screen. Scan data are represented as four-digit hexadecimal
values, each value corresponding to one word of raw telemetry. These data have slightly
different formats, depending on the mode of CAST-V operation (OPEN/CASED).
In openhole mode (OPEN), each firing of the measurement transducer produces two
words of telemetry. For instance, the first shot in a scan consists of the first two words;
the second shot consists of the next two words. The first hexadecimal word can be
broken down into bytes. In Figure B-4, byte 1 is the system gain of the peak window in
3-dB steps, and byte 2 is the peak amplitude in raw ADC counts. The second
hexadecimal word (bytes 3 and 4) is the transit time pick in 0.2-µs counts. The data for
the next shot reside at words 3 and 4 (bytes 5 through 8), and the pattern repeats. Inopenhole mode, there are 200 shots per scan.
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B-8 CAST-V PC Monitor Program 770.00696-NW 07/97
Scan ID
Mtr Speed (rps)
Tool Mode
Gate Start (us)
Casing O.D.Eff. Radius
Version
Wfm. Flag
160
5.0
OPEN
30.0
00
C
OFF
0
12
24
36
48
60
72
84
96
108
120
132
144
156
952
952
952
952
952
952
952
952
952
952
952
952
952
952
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
952
INCLX (V)
INCLY (V)
MAGX (V)
MAGY (V)
Motor V (V)Motor I (A)
Temp (Deg C)
Shot 1 Pk (V)
-2.181
-2.210
-1.562
-2.000
0.207-0.006
-1236.569
0.90598
Mud Pk
Mud Pk Gain
Mud DT (us)
Mud Sum
Mud Sum GainMud Target Tk
Azimuth (Deg)
Shot 1 DT (us)
0.90598
10
53.0
0
00
232.0
54.0PEAK AMP
GAIN
TRANSIT TIME
Figure B-4: Scan Data for Openhole Mode
In cased-hole mode (CASED), each transducer firing produces four words of telemetry.
In Figure B-5, byte 1 is the system gain of the peak window and byte 2 is the peak
amplitude. The second hexadecimal word (bytes 3 and 4) is the transit time pick. The
third hexadecimal word (bytes 5 and 6) is the sum of the resonance window. Byte 7 is
the system gain of the resonance window, and byte 8 is the thickness step2 of the casing.
The data for the next shot reside at words 5 through 8 (bytes 9 through 16), and the
pattern repeats. In cased-hole mode, there are 100 shots per scan.
2 (Thickness step × 0.002 in./step) + 0.2 in. = casing thickness.
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Scan ID
Mtr Speed (rps)
Tool Mode
Gate Start (us)
Casing O.D.
Eff. RadiusVersion
Wfm. Flag
94
4.9
CASED
30.0
0
0C
OFF
0
12
24
36
48
60
72
84
96
108
120
132
144156
957
957
957
957
957
957
957
957
957
957
957
957
957957
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E
10E10E
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
11321132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
11321132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
1132
11321132
957
957
957
957
957
957
957
957
957
957
957
957
957957
957
957
957
957
957
957
957
957
957
957
957
957
957957
863
863
871
873
872
86B
867
86F
86B
868
879
86A
874867
86A
865
873
86A
869
877
86C
86C
872
86A
875
877
86C868
86C
866
868
875
86C
869
86E
870
86A
875
86A
870
87586D
INCLX (V)
INCLY (V)
MAGX (V)
MAGY (V)
Motor V (V)
Motor I (A)Temp (Deg C)
Shot 1 Pk (V)
-2.650
-2.689
-1.746
-2.377
0.277
-0.006-1402.950
0.96122
Mud Pk
Mud Pk Gain
Mud DT (us)
Mud Sum
Mud Sum Gain
Mud Target TkAzimuth (Deg)
Shot 1 DT (us)
0.96122
8
54.6
2910
18
300233.7
54.0PEAK AMP
GAIN
TRANSIT TIME RESONANCE SUM RESONANCE GAIN
THICKNESS STEP