060070 Meridian Gyrocompass

Contents

CAUTIONARY NOTICESYour attention is drawn to the following cautionary notices that apply throughout this Manual.

WARNINGThe Meridian Gyrocompass weighs 15.5kg. To avoid personal injury, take proper precautions if you lift or move the equipment.

WARNINGThere is a danger of serious injury from voltages inside the Meridian Gyrocompass. Do not remove the gyrocompass cover unless you have the necessary skills and experience to perform maintenance work on a system of this nature. Always power-off the system before you remove the cover for maintenance work.Observe all local safety regulations as you work on the equipment. Reconnect the safety grounding straps and refit all safety covers to the equipment before you power-on the system.

WARNINGThe Meridian Gyrocompass should be supplied with power from an SELV source as defined in IEC/EN 60950. The power supply source should be switched and protected by a suitable circuit breaker.

CAUTIONThe Meridian Gyrocompass includes precision components and bearings. To avoid causing damage to any part of the System, handle all items with care.

Retain the original packing cases so that you can use them to transport the system when necessary. You will void the warranty if you use improper packing during transportation.

CAUTIONSevere damage to the Meridian Gyrocompass can occur if you move the gyrocompass while the rotor is still spinning without the servo system in operation.

Note that the gyro rotor continues to spin for approximately five minutes after you power-off the system.

To avoid potential damage to the Meridian Gyrocompass, always allow a period of five minutes after power-off for the gyro rotor to come to rest before you attempt to move the gyrocompass.

DPN 060070 © TSS (International) Ltd Issue 3.11 Page 1 of 6

Meridian Gyrocompass

CAUTIONDuring operation, the gyrocompass must remain level to within ±45°. If it experiences tilt greater than 45° in any direction, it will ‘topple’.

Never apply a tilt of more than 45° with the gyro rotor spinning or during the gyrocompass initialisation procedure. Note that the gyro rotor continues to spin for approximately five minutes after you power-off the System.

CAUTIONIf you install the gyrocompass in an enclosed space, make certain there is sufficient ventilation and circulation of free air to allow effective cooling.

CAUTIONPerform maintenance instructions only if you have the skills and experience required, and only when necessary. Inappropriate tampering with the internal controls and components of the gyrocompass can lead to damage or serious performance degradation.NEVER open the gyrocompass cover or make any adjustments inside the gyrocompass unless you are entirely confident in your actions.

CAUTIONRemove power from the gyrocompass before making any connections to external equipment.

CAUTIONYou will void the warranty if you make any modifications to this equipment without prior permission from TSS (International) Ltd.

DO NOT modify this equipment in any way without obtaining permission from TSS (International) Ltd.

CAUTIONYou will void the warranty if you operate the gyrocompass outside the environmental conditions detailed in Section 4 and in BS EN 60945.

Page 2 of 6 Issue 3.11 © TSS (International) Ltd DPN 060070

Contents

CONTENTS

1 INTRODUCTION 1–11.1 System Description 1–31.1.1 Gyrocompass 1–31.1.2 Remote Control Unit 1–41.1.3 Auxiliary Inputs 1–51.1.4 Heading Outputs 1–5

1.2 Principle of Operation 1–5

2 INSTALLATION 2–12.1 Unpacking and Inspection 2–22.2 Physical and Electrical Installation 2–32.2.1 Selecting a location 2–32.2.2 Gyrocompass installation 2–42.2.3 External Remote Control Unit 2–102.2.4 Set the Gyrocompass DIP Switches 2–11

2.3 Alignment 2–132.4 Final Gyrocompass Installation Tests 2–132.5 Installation Drawings 2–14

3 OPERATING INSTRUCTIONS 3–13.1 Control Features 3–23.2 Initial Power-on 3–33.3 Operating Procedure 3–43.3.1 Latitude correction 3–43.3.2 Speed correction 3–53.3.3 DG operating mode 3–5

3.4 Error Modes 3–63.4.1 Loss of GPS 3–63.4.2 Loss of speed log 3–63.4.3 Gyrocompass system warnings and failures 3–7

3.5 Operating Considerations 3–93.5.1 General Operating Considerations 3–93.5.2 Corrections for Speed and Latitude 3–103.5.3 Operating at Extremes of Latitudes 3–103.5.4 Operating Considerations for Vessel Dynamics 3–10

4 TECHNICAL DATA 4–14.1 Specifications 4–14.1.1 Power Requirements 4–14.1.2 Performance (definitions as in ISO 8728) 4–14.1.3 Compensation 4–14.1.4 Environment 4–14.1.5 Signal Inputs 4–24.1.6 Signal outputs 4–24.1.7 Dimensions and Weight 4–24.1.8 Listener load requirement 4–34.1.9 Talker drive capability 4–3



4.1.10 Standards 4–34.2 Data Formats 4–44.2.1 IEC 61162 Serial Data Formats – General information 4–54.2.2 Inputs 4–64.2.2.1 IEC 61162 input signals 4–64.2.2.2 Pulsed input 4–10

4.2.3 Outputs 4–114.2.3.1 IEC 61162 output signals 4–11

4.2.4 IEC 61162 sentence with Checksum 4–154.2.5 Other Output Formats 4–164.2.5.1 Course Recorder Output 4–164.2.5.2 Synchro Output 4–164.2.5.3 Resolver Output 4–164.2.5.4 Stepper S-Code 4–174.2.5.5 Rate of Turn 4–17

5 MAINTENANCE 5–15.1 Built-in Test Equipment 5–15.1.1 Azimuth Drift Adjustment 5–25.1.2 Azimuth Bias Adjustment 5–3

5.2 Test Connector 5–35.3 Diagnostic Output Sentence 5–6


Contents

TABLE OF AMENDMENTS

Old Issue New Issue Date Details

- 2.0 11 May 2000 New release.

2.0 2.0A 12 Dec 2000 Corrected identification of Azimuth Bias potentiometer and other details. Include DIP switch default settings.

2.0A 2.0B 1 Mar 2001 Modify power connection details.

2.0B 2.0C 23 Apr 2001 Add notification to avoid product modifications.

2.0C 3.0 Aug 2002 Substantial amendments to reflect product enhancements.

3.0 3.1 Sept 2002 completion of enhancement features including compliance with IEC 61162.

3.1 3.2 Jan 2003 Minor amendments and description of Diagnostic Output Sentence.

3.2 3.3 Feb 2003 Modification to specifications and addition of Appendix B to demonstrate Certificate of Type Approval.

3.3 3.4 Mar 2003 Minor amendments to a display warning and a note referring to confirming software release.

3.4 3.5 July 2003 Note added regarding modification kit available for alternative orientations when attempting correct speed compensation.

3.5 3.6 August 2003 Minor amendments to specifications throughout.

3.6 3.7 March 2004 Amendments to alarm warning / failure designation.

3.7 3.8 March 2005 Details for High Speed Craft (HSC) operation.

3.8 3.9 May 2005 Updated Distribution board connections and drawing.

3.9 3.9.1 September 2005 Added paragraph to section 3.5.4 explaining potential conflicts with earth connections on distribution board for the HSC.

3.9.1 3.10 June 2006 Revised Company Logo

3.10 3.11 January 2008 Replaced manual setting of DG Mode on distribution board with Alarm Acknowledgement functionality. This enables compatibility with the Compass Changeover System.




Introduction

1 INTRODUCTIONThe Meridian Gyrocompass is a master heading reference instrument that applies the characteristics of a dynamically tuned gyroscope and the effects of gravity and earth rotation to provide a true north reference.

The Meridian Gyrocompass specification makes the System ideal for installation and operation on board vessels of almost any size and in a wide range of applications.

Among the standard features of the Meridian Gyrocompass are:

❐ A short settling time

❐ Operation from a 24V DC electrical supply

This Manual is an important part of the Meridian Gyrocompass. It describes the System and contains full installation and operating instructions. You should retain the Manual with the System for use by personnel who will install and operate it.

Installation and operation of the Meridian Gyrocompass are not complex tasks. However, you should spend time to familiarise yourself with the contents of this Manual before you start to install or use the System. Time spent in identifying the task sequence now will ensure your System is operational in the minimum of time.

WARNINGSWhere appropriate, this Manual includes important safety information highlighted as WARNING and CAUTION instructions. You must obey these instructions:WARNING instructions alert you to a potential risk of death or injury to users of the System.

CAUTION instructions alert you to the potential risk of damage to the System.For your convenience, the Contents section includes copies of all the WARNING and CAUTION instructions included in this Manual.

Throughout this Manual all measurements conform to the SI standard of units unless otherwise indicated.

DPN 060070 © TSS (International) Ltd Issue 3.10 Section 1 Page 1 of 6


For your convenience, this Manual includes several sections, each of which describes specific features of the Meridian Gyrocompass:

You should read sections 1 and 2 before you attempt to install the System:Section 1 contains introductory notes and describes those items supplied as

standard.

Section 2 describes how to select a suitable location for the gyrocompass. This section includes full instructions to install the System and connect it to external equipment.

You should read sections 3 and 4 before you use the System:Section 3 describes how to operate the Meridian Gyrocompass.

Section 4 includes the System specifications and descriptions of the data formats.

You should read sections 5 if you suspect a fault on the System:Section 5 describes how to use the internal 60-way test connector and explains

how to conduct simple adjustments with the gyrocompass housing removed.

This Manual also contains the following appendices:Appendix A explains how a gyroscope can be made north seeking for use in a

gyrocompass.

Appendix B contains copies of Type Approval Certificates.

CAUTIONYou will void the warranty if you make any modifications to this equipment without prior permission from TSS (International) Ltd.DO NOT modify this equipment in any way without obtaining permission from TSS (International) Ltd.

Section 1 Page 2 of 6 Issue 3.10 © TSS (International) Ltd DPN 060070

Introduction

1.1 SYSTEM DESCRIPTIONThe Meridian Gyrocompass comprises two sub-assemblies:

❐ The gyrocompass housing

❐ The Remote Control Unit (RCU)

Figure 1–1 shows the combined gyrocompass housing with the RCU included as an integral unit.

The Meridian Gyrocompass applies dynamic tuning to settle automatically to the meridian. Due to the physical principles of a north-seeking gyrocompass, achievable accuracy depends on the operating latitude and the vessel dynamics. To optimise its performance, the Meridian Gyrocompass uses information supplied by external equipment, for example a GPS receiver and a speed log, to apply latitude and speed corrections.

Refer to Appendix A for a simplified explanation of the gyrocompass theory of operation.

1.1.1 GYROCOMPASSFigure 1–1: Gyrocompass housing with integral RCU

Figure 1–1 shows the gyrocompass housing, which contains the following items:

❐ True north seeking dynamically tuned precision gyroscope and gimbal suspension assembly.

❐ Power supply board.

❐ Digital and analogue control boards.

❐ RFI filter and distribution board.

It is a relatively simple operation to install the gyrocompass and you should be able to accomplish this quickly without the need for specialised personnel or equipment. However, note that the gyrocompass weighs 15.5kg and you must take due care when you lift and move it.



The care that you take when you align the gyrocompass housing with the surveyed fore-aft axis of the vessel will have a direct impact on the accuracy of heading measurements delivered by the System. Since the Meridian Gyrocompass is an ideal source of heading information for use by other systems on board, such as radars and satellite communication antennas, the accuracy of its heading measurements will have a wide impact throughout the vessel. You should therefore take care when you install and align the gyrocompass. Refer to Section 2 for full instructions to install, connect and align the Meridian Gyrocompass.

The only component available for user servicing is a 3.15A line fuse inside the gyrocompass housing. In case of failure, refer to Section 5 for instructions on fault diagnosis and maintenance.

1.1.2 REMOTE CONTROL UNITFigure 1–2: Remote Control Unit

The Remote Control Unit (RCU) provides all the functions and indicators necessary to control and operate the Meridian Gyrocompass.

The four-character LED can show a range of information:

❐ Heading in Degrees. 000.0 to 359.9

❐ Latitude. 80S to 80N

❐ Latitude Source

❐ Speed in Knots. 00 to 90

❐ Speed Source

❐ Alarms and Status information

❐ Separate LED indicators show Power On and Compass Ready conditions

Refer to Section 3 for instructions to operate the Meridian Gyrocompass.


Introduction

1.1.3 AUXILIARY INPUTSAuxiliary inputs may be used for the Meridian Gyrocompass to apply latitude and speed corrections.

Ideally, the Meridian Gyrocompass should accept latitude and speed information from external sources such as a GPS receiver or a speed log. However, you may supply this information manually if external sources are not available. The advantage of using GPS or a speed log to provide correction signals is that they allow automatic corrections to be applied without operator intervention.

Section 2 includes instructions to connect and configure the external sources of latitude and speed information.

Section 3 includes instructions to set the latitude and speed manually.

1.1.4 HEADING OUTPUTS

The Meridian Gyrocompass is a self-contained precision navigation instrument that is capable of supplying heading reference information simultaneously to a wide range of equipment on board the vessel. Throughout a typical vessel, applications that can use information supplied by the Meridian Gyrocompass include:

❐ Autopilot

❐ Radars

❐ GPS

❐ Radio direction finder

❐ Course plotter and recorder

❐ Satellite communication systems

❐ Satellite television

To support this wide range of equipment types, the Meridian Gyrocompass can supply heading information simultaneously through multiple channels using any of the common transmission formats.

Refer to Section 4 for a description of the available output channels and their data formats. Refer to Section 2 for details on how to interconnect to other equipment.

1.2 PRINCIPLE OF OPERATIONIn the absence of external influences, a free-spinning gyroscope will try to maintain a fixed orientation in space. The Meridian Gyrocompass exploits this property and uses gravity control and earth rotation to align the gyroscope spin axis with the meridian, i.e. the true north direction.

Refer to Appendix A for the general theory of gyrocompass operation.




Installation

2 INSTALLATIONTo obtain the best performance from the Meridian Gyrocompass you must take care when you install and connect it. This section includes all the information and instructions you will need to complete these tasks.

You should read this section carefully and understand the important instructions that it contains before you begin to install or connect the equipment.

2.1 Unpacking and Inspection Page 2Explains the inspection checks that you should perform as you unpack the Meridian Gyrocompass.

2.2 Physical and Electrical Installation Page 3Choose a suitable location to install the Meridian Gyrocompass. Connect the system to an electrical supply and to external equipment.

2.3 Alignment Page 13The care that you take as you align the Meridian Gyrocompass with the fore-aft datum on the vessel will have a direct influence upon its accuracy.



2.1 UNPACKING AND INSPECTION

WARNINGThe Meridian Gyrocompass weighs 15.5kg. To avoid personal injury, take proper precautions if you lift or move the equipment.

CAUTIONThe Meridian Gyrocompass includes precision components and bearings. To avoid causing damage to any part of the System, handle all items with care.

Retain the original packing cases so that you can use them to transport the system when necessary. You will void the warranty if you use improper packing during transportation.

CAUTIONSevere damage to the Meridian Gyrocompass can occur if you move the gyrocompass while the rotor is still spinning without the servo system in operation.

Note that the gyro rotor continues to spin for approximately five minutes after you power-off the system.

To avoid potential damage to the Meridian Gyrocompass, always allow a period of five minutes after power-off for the gyro rotor to come to rest before you attempt to move the gyrocompass.

The Meridian Gyrocompass undergoes a full series of electrical and mechanical tests during manufacture and before dispatch. The packing case has a special design to protect the contents against shock during transit so that the equipment should arrive without damage or defect.

As soon as possible after you have received the system, check all items against the shipping documents. Inspect all sub-assemblies carefully to check for any damage that may have occurred during transportation. If you see any damage file a claim with the carrier and immediately notify TSS (International) Ltd.

To avoid loss or damage to any components of the system, store all sub-assemblies safely in the packing case until you need to install them. Obey the storage temperature limits listed in Section 4.

Notify TSS (International) Ltd immediately if there are any components missing from the shipment.

The title page of this Manual lists the contact details for TSS (International) Ltd.


Installation

2.2 PHYSICAL AND ELECTRICAL INSTALLATION2.2.1 SELECTING A LOCATIONThere are certain guidelines that you should follow to install the Meridian Gyrocompass successfully:

CAUTIONDuring operation, the gyrocompass must remain level to within ±45°. If it experiences tilt greater than 45° in any direction, it will ‘topple’.

Never apply a tilt of more than 45° with the gyro rotor spinning or during the gyrocompass initialisation procedure. Note that the gyro rotor continues to spin for approximately five minutes after you power-off the System.

❐ The gyrocompass weighs 15.5kg. Choose a mounting location that is level, flat and sufficiently strong to support the unit without flexing or experiencing extreme vibration. The mounting location can be open, as on a chart table, or enclosed within a cabinet.

CAUTIONIf you install the gyrocompass in an enclosed space, make certain there is sufficient ventilation and circulation of free air to allow effective cooling.

❐ Choose a location that protects the Meridian Gyrocompass from damage.

❐ Do not install or operate the Meridian Gyrocompass where the ambient temperature could fall below 0°C or rise above +45°C, or where rapid changes of temperature can occur.

❐ Do not install the Meridian Gyrocompass close to strong mechanical or electrical noise sources, or in a location susceptible to vibration or shock.

❐ Allow a minimum distance of 0.4m between the gyrocompass housing and any standard magnetic compasses.

❐ Choose a location that allows convenient access to install, connect and service the Meridian Gyrocompass. Refer to Figure 2–6 for clearance dimensions.



2.2.2 GYROCOMPASS INSTALLATIONYou must align the Meridian Gyrocompass so that its fore-aft axis is parallel to the fore-aft datum on the vessel. Any misalignment between the gyrocompass housing and the vessel will have a direct effect on the accuracy of heading measurements delivered by the system.

To install the Meridian Gyrocompass you will need the following tools:

❐ Screwdriver 5.5mm × 150mm

❐ Screwdriver 3mm × 75mm

❐ Nut spinner 5.5mm

❐ 8.5mm drill

❐ 3 x M8 bolts of suitable length complete with washers and nuts

❐ Combination spanner 10mm

❐ Adjustable spanner opening to at least 33mm

❐ Suitable cables for the installation as indicated in Table 2–1 .

There should be no need to remove the gyrocompass cover during installation. You may gain access to make signal connections by removing the gland plate assembly, comprising the Gland Plate and the Distribution Board. There is a removable panel on the top of the gyrocompass that allows access to the internal DIP switches and a 60-way test connector.

1. During installation you must align the Meridian Gyrocompass so that its fore-aft axis is parallel with the fore-aft datum on the vessel. It is not necessary for the gyrocompass to be on the vessel centre line. There are alignment marks on the base of the Meridian Gyrocompass to help you achieve the correct alignment.

2. Three elongated securing holes machined into the gyrocompass base allow you to make fine adjustments to alignment after installation. With the gyrocompass positioned accurately, mark the supporting surface with the centre positions for the three securing holes. Refer to Figures 2–5 and 2–6 for dimensions.

3. Remove the gyrocompass and drill three 8.5mm diameter holes, using the marks you have just made on the supporting surface as hole centres. Deburr the holes and remove any swarf.

Table 2–1: Suitable cable types

Purpose Suitable cable

Power supply 7/0.5mm (1.5mm2) HOFR sheathed to BS6883

Synchro heading outputResolver heading outputStepper S-code output

7/0.4mm (1.0mm2) butyl or EP rubber insulated, CSP sheathed, wire braided and CSP oversheathed.

Serial data heading outputSerial data speed inputSerial data latitude input

1/0.85mm (0.6mm2) twisted pair, butyl or EP rubber insulated, CSP sheathed, wire braided and CSP oversheathed.


Installation

4. Reposition the gyrocompass and align it to the fore-aft datum. Use three M8 bolts with washers and nuts to secure the gyrocompass in position.

5. Connect a 24V electrical supply (acceptable range 18V to 36V DC) to the Meridian Gyrocompass at J1, the three-pin power inlet on the Gland Plate. Figure 2–1 shows the Gland Plate.

To prevent any possibility of damage to the gyrocompass while the vessel is moving it is recommended that an uninterruptable electrical supply is used to power the Meridian Gyrocompass.

6. Connect the ship’s safety ground to the earthing stud adjacent to the power connector.

Figure 2–1: Gyrocompass gland plate

CAUTIONRemove power from the gyrocompass before making any connections to external equipment.

Fuse

3.15AF

Compass Min. Safe Dist.

Build Standard No.

Serial No.

Mfg. Date

m

Watford, England.

CAUTION

Before removing the cover or the RCU

unit, remove the gland plate and

disconnect the RCU cable (TB1/17-22)

from the distribution board.

Gland plate release screws

Cover plate release screws



7. Make all necessary signal connections to the Meridian Gyrocompass at the Distribution Board. The Distribution Board accepts open tails for all connections. Pass cables through available glands in the Gland Plate. Glands A, D, E, F and J (identified in Figure 2–5) accept cables up to 18mm diameter, while all other glands accept cables up to 14mm diameter. Refer to Figure 2–3, and Tables 2–3 and 2–4 for cable connection details.

8. To maintain EMC compliance, connect all the wire braiding on the cables to the M3 grounding posts on the inside surface of the Gland Plate as shown in Figure 2–2.

Figure 2–2: Termination of wire braided cables

9. Refit the Gland Plate, making certain there are no trapped wires or cables.


Installation

Figure 2–3: Gyrocompass distribution board

Table 2–2: J1 – Power supply input pin details

Pin Description

1 Protective ground

2 +24V DC

3 0V

T B 6T B 5 T B 8T B 7

T B 4



Table 2–3: Input Signals

Signal description Signal type Distribution Board connector

Alarm Acknowledgement Voltage free contact close TB1/1(N/O) TB1/2 (CC)

GPS input IEC 61162 RS232 TB1/3 TB1/4 (0V)

GPS input IEC 61162 RS422 TB1/5 (A) TB1/6 (B)

Log input IEC 61162 RS232 TB1/7 TB1/8 (0V)

Log input IEC 61162 RS422 TB1/9 (A) TB1/10 (B)

Log OK TB1/11 TB1/12 (0V)

Log TTL pulses TB1/13 (+) TB1/14 (0V)

Log relay Voltage free contact close TB1/15 (+) TB1/16 (0V)

RCU 24V in TB1/17 (+) TB1/18 (–)

RCU On/Off TB1/19 (N/C) TB1/20 (ON)

RCU Communications RS422 TB1/21 (S+) TB1/22 (S-)

Rx Spare – TB1/23 TB1/24 (0V)


Installation

Table 2–4: Output Signals

Signal description Signal type Distribution Board connector

Channel 2 IEC 61162 RS232 (all data) TB2/1 TB2/2 (0V)

Channel 1 IEC 61162 RS232 (all data) TB2/3 TB2/4 (0V)

Channel 2 IEC 61162 RS422 (all data) TB2/5 (B) TB2/6 (A) TB4 (C)

Channel 1 IEC 61162 RS422 (all data) TB2/7 (B) TB2/8 (A) TB4 (C)

Heading TTL S-type TB2/9 (5V) TB2/10 (L1)TB2/11 (L2) TB2/12 (L3)TB2/13 (0V)

Heading Synchro/resolver TB2/14 (36V) resTB2/15 (26V) synTB2/16 (0V) syn/resTB2/17 (S1) synTB2/18 (S1) resTB2/19 (S2) syn/resTB2/20 (S3) syn/resTB2/21 (S4) res

Gyro fail Voltage free contact closure TB2/22 (CC)TB2/23 (normally closed, opens on failure)TB2/24 (normally open, closes on failure)

System Fail TTL TB2/25 TB2/26 (0V)

Gyro ready Voltage free contact closure TB2/27 (CC)TB2/28 (open when not ready, closes when ready)TB2/29 (closed when not ready, opens when ready)

Gyro ready TTL TB2/30 TB2/31 (0V)

Channel 2 IEC 61162 RS232 TB3/1 TB3/2 (0V)



Channel 2 IEC 61162 RS422 TB3/7 (B) TB3/8 (A) TB5 (C)









Rate of turn Analogue ±10V TB3/25 TB3/26 (0V)

Course recorder IEC 61162 RS232 TB3/27 TB3/28 (0V)



2.2.3 EXTERNAL REMOTE CONTROL UNITThe standard Meridian Gyrocompass has the Remote Control Unit (RCU) mounted integrally and available for immediate operation.

There may be applications where you prefer to install the RCU at some distance from the gyrocompass unit. A mounting kit, part number 929190, is available to use in these circumstances. The kit includes the following items:

❐ RCU housing

❐ Mounting bracket

❐ Blanking plate for the gyrocompass housing

There is no need to remove the gyrocompass cover to install the RCU externally:

1. Release and remove the four M3 screws at the corners of the RCU that secure it to the gyrocompass housing.

2. Remove the seven Gland Plate release screws marked A in Figure 2–1. Remove the Gland Plate. Note the connection sequence of the RCU cable at TB1/17–22 so that you can restore the same connections through the extension cable.

3. Disconnect the RCU cable at TB1/17–22.

4. Lift the RCU away from the gyrocompass.

The cable run between the gyrocompass and RCU must not exceed 100 metres.

5. Use the bracket with the mounting kit to fix the RCU to a desk or to a bulkhead. You may also flush mount the RCU in a panel. Choose a suitable location to mount the RCU:

❐ The mounting surface can be vertical or horizontal according to requirements.

❐ Avoid installing the RCU where it might experience severe shock or vibration.

❐ Choose a location for the RCU that allows a clear view of the display.

6. Use the two star knobs supplied to fit the RCU into the mounting bracket. Tilt the unit to a convenient viewing and operating angle and then lock it in place by tightening both star knobs.

7. Supply and fit a cable to connect the RCU to TB1/17–22 on the Distribution Board. The cable must have three screened twisted pairs and should not exceed 100 metres in length. Route the cable through a vacant cable gland on the Gland Plate and make the correct connections to the TB1 terminals.

8. Refit the Gland Plate and secure it in place using the seven release screws.

9. Fit the blanking plate to fill the gap left in the cover by the RCU.

Section 2 Page 10 of 18Issue 3.11 © TSS (International) Ltd DPN 060070

Installation

2.2.4 SET THE GYROCOMPASS DIP SWITCHES

1 There is a removable panel on top of the gyrocompass that allows access to the two internal DIP switches (shown in Figure 2–4) without the need to remove the main gyrocompass cover. Release and remove the three securing screws to lift off the panel.

2. Refer to Tables 2–5 and set the DIP switches carefully for the specific requirements of your installation. Do not adjust the settings of other preset controls inside the gyrocompass.

3. Refit the access panel to the top of the gyrocompass cover.

Figure 2–4: Location of DIP switches.



The DIP switch settings described in this table are only applicable to gyrocompasses fitted with software versions BPR 0161 (Main) and BPR 0114 (RCU) or later. If necessary, you can view the software versions of the main and the RCU processors by pressing both the Up and the Down selection buttons simultaneously. The display will toggle between indications of the main processor software version (with prefix 'M') and the RCU software (with prefix 'R'). The display will continue to toggle for several seconds after you release the buttons and will then return to the heading indication.

Table 2–5: SW1 and SW2 DIP switch settingsFactory default settings appear in bold and are marked with an asterisk in this table.

SW1 DIP Switches SW2 DIP Switches

Switch number

and settingFunction

Switch number

and settingFunction

1OnOffOnOff

2OnOnOffOff

Speed Log Input Type100 pulses per nautical mile200 pulses per nautical mile400 pulses per nautical mileLOG Serial Data*

1On

Off

Output Sentences typesAnalogue ROT Scaling +/- 60deg/minute = +/- 10VAnalogue ROT Scaling +/- 20deg/s = +/- 10V*

2OnOff

Channel 2 Heading decimal placesTwo decimal placesOne decimal place*

3OnOffOnOff

4OnOnOffOff

Channel 1 Baud / Update rate38k4 50Hz9600 10Hz4800 10Hz4800 1Hz

3OnOff

Channel 1 Checksum fieldChecksum transmittedNo Checksum transmitted*

4OnOff

Channel 2 Checksum fieldChecksum transmittedNo Checksum transmitted*

5OnOffOnOff

6OnOnOffOff

Channel 2 Baud / Update rate38k4 50Hz9600 10Hz4800 10Hz4800 1Hz

5 OnOffOnOff

6OnOnOffOff

Channel 1 Output SentencesAll Data (1Hz only)HDT + ROTROT onlyHDT only*

7OnOff

Channel 1 Heading Decimal placesTwo decimal placesOne decimal place*

7 OnOffOnOff

8OnOnOffOff

Channel 2 Output SentencesAll Data (1Hz only)HDT + ROTROT onlyHDT only*

8On

Off

Vessel DynamicsFor HSC applications(for serial numbers later than 3500)Standard Control Mode*

Notes: 1. If you set All Data Output Sentence, the update rate will default to 1Hz.2. For full IEC 61162 compliance, a checksum must be transmitted.


Installation

2.3 ALIGNMENTIt is important to align the gyrocompass to the vessel accurately. Any misalignment between the housing and the vessel will appear directly as a fixed error in heading measurements. Because measurements from the Meridian Gyrocompass are available for use by diverse systems around the vessel, any misalignment between the gyrocompass and the fore-aft datum might have a significant impact in many other areas of application.

There are several methods you may use to align the gyrocompass to the vessel fore-aft datum:

❐ Align the gyrocompass to the fore-aft datum using a known reference line, such as a surveyed bulkhead or frame member. The marks on the gyrocompass base plate are precision indicators of the gyrocompass alignment orientation.

To achieve correct speed compensation, the gyrocompass must be orientated so that the gland plate faces the forward end of the vessel. Note that modification kits are available for alternative gyrocompass orientations.

❐ Use the services of a marine surveyor to align the gyrocompass precisely with the fore-aft datum.

Remove any residual misalignment by making minuscule adjustments to the gyrocompass mounting plate. When you have achieved perfect alignment, tighten the securing bolts fully to lock the gyrocompass in position.

2.4 FINAL GYROCOMPASS INSTALLATION TESTSAfter you have installed the gyrocompass and power supplies are available to it, perform the following installation tests:

1. Power-on the gyrocompass by following the instructions in sub-section 3.2. Wait for three hours before you perform the following tests.

2. Check the vessel heading against a known reference mark on a chart. Typically this could be the alongside position of the fitting-out dock. Alternatively, accurately survey an object at least five kilometres ahead of the vessel using the fore-aft line as a datum.

3. Check the displayed gyrocompass heading at intervals to make certain it is consistent with the surveyed vessel heading.

4. If there is an error larger than ±0.5°, re-check the vessel fore-aft datum to confirm that it is correct.

5. Check that all the repeaters are accurately aligned with the gyrocompass heading and make certain they maintain their alignment at all times while the gyrocompass is powered-on.



2.5 INSTALLATION DRAWINGSFigure 2–5: Gyrocompass installation – Sheet 1

30 330340

170

110

160

SE130

140

120

150

7090

8010

0E

NE60

40

50

250

230

190180 200S 210 220

SW 240

N

NW

320

27 0260

W280

300290

310

20 10 0 350

24VDC Fuse3.15AF

CAUTIONBefore removing the cover or the RCU

unit, remove the gland plate anddisconnect the RCU cable (TB1/17-22)



Installation

Figure 2–6: Gyrocompass installation – Sheet 2

30 330340

170

110

160

SE130 140

120

1 5 0

7090

8010

0E

NE60

40

50

250

230

190180 200S

210 220SW 24 0

N

NW

320

27 0260

W280

300290

310

20 10 0 350

24VDC Fuse3.15AF

CAUTIONBefore removing the cover or theRCU

unit, remove the gland plate anddisconnect the RCU cable (TB1/17-22)




Figure 2–7: RCU installation – Table mount


Installation

Figure 2–8: RCU installation – Flush mount




Operation

3 OPERATING INSTRUCTIONSThis section explains how to power-on and configure the Meridian Gyrocompass after installation. Refer to Section 4 for an explanation of the data formats relevant to the System.

3.1 Control Features Page 2The RCU provides all the controls you will need to operate the Meridian Gyrocompass. It also includes a four-character display panel that shows the heading indication, any alarm messages and error codes.

3.2 Initial Power-on Page 3Explains how to power-on the Meridian Gyrocompass after installation and describes the initialisation sequence.

3.3 Operating Procedure Page 4Explains how to select the latitude and speed correction sources, and how to set the latitude and speed manually if necessary.

3.4 Error Modes Page 6Identifies the system error modes. Use these indicators to identify a possible fault condition.

3.5 Operating Considerations Page 9Includes general advice for operating the Meridian Gyrocompass on a vessel and on high speed craft.



3.1 CONTROL FEATURESFigure 3–1: RCU front panel features

The RCU front panel includes all the operator controls for the Meridian Gyrocompass:Table 3–1: RCU Control and Indicator functions

Control Function

Power switch. Recessed to prevent accidental operation.

Selection Up. Press to increase display brightness.

Selection Down. Press to decrease display brightness

Latitude. Press to display current Latitude source and correction value. Use in conjunction with the Selection Up and Selection Down buttons to pre-set Latitude source and correction value.

Speed. Press to display current Speed source and correction value. Use in conjunction with the Selection Up and Selection Down buttons to pre-set Speed source and correction value.

Alarm. Press to silence the audible alarm.

012.3 Four digit alphanumeric display.Note: The display can show additional information by alternating the display contents at 0.5Hz. This is indicated throughout the manual as, for example, L52N + SGPS

Power lamp (red) Indicates that the Meridian Gyrocompass is switched on when 24V DC nominal power is connected.

Ready lamp (green)

Indicates that the Meridian Gyrocompass has settled and a True Heading is available.

Table 3–2: RCU display formats

Format Function

Heading0123.40123.4 + DG0123.4 + DG_L

Heading OnlyHeading with DG mode set at the RCUHeading with DG mode set by latitude greater than 80 deg


Operation

3.2 INITIAL POWER-ONThe Meridian Gyrocompass starting cycle is fully automatic after power is applied. For correct operation Latitude and Speed correction must be applied.

1. Check that there is a nominal 24V DC electrical supply available to the gyrocompass. The acceptable supply range is 18V to 36V DC.

To ensure continuous operation, the power supply for this unit should have a 200W power rating.

2. To start the Meridian Gyrocompass press the power switch on the RCU.

3. Check that the red ‘Power’ lamp on the RCU illuminates. This lamp indicates only that the Meridian Gyrocompass is receiving power and does NOT indicate a settled condition. The instrument illumination will be at maximum during the initialisation sequence. Even at its maximum setting, the instrument illumination may be difficult to see in bright ambient lighting.

4. The RCU will activate the audible alarm for about 1 second. The display will indicate T.E.S.T. and the ‘Ready’ lamp will be lit for about 10 seconds while the system performs a series of self-tests. After successful completion of the self-tests, the display will show the current Gyrocompass dial heading and the ‘Ready’ lamp will go off until the Gyrocompass has settled.

Initially the indicated heading could be inaccurate by as much as 180°. The indicated heading should not be relied on until the Gyrocompass has settled, indicated by an illuminated ‘Ready’ lamp.

5. Set the source of latitude information by following the instructions in sub-section 3.3.1.

6. Set the source of speed information by following the instructions in sub-section 3.3.2.

Speed (by pressing the Speed button)S_01 + S.MANS_01 + S.GPSS_01 + S.LOGS_01 + P.LOG

Speed value with Manual selected speed sourceSpeed value with GPS selected speed sourceSpeed value with LOG selected speed source (serial data input)Speed value with LOG selected speed source and Pulse Log DIP switch set (pulse input)

Latitude (by pressing the Latitude button)L.52N + L.MAN

L.52S + L.MAN

L.52N + L.GPS

Latitude value in the Northern Hemisphere with Manual selected Latitude sourceLatitude value in the Southern Hemisphere with Manual selected Latitude sourceLatitude value with GPS selected Latitude source

Table 3–2: RCU display formats

Format Function



7. Use the Selection Up and Selection Down buttons to adjust the RCU illumination level to a comfortable setting.

8. Wait for the gyrocompass to settle. This will occur automatically and will take upwards of 24 minutes depending on initial heading offset and sea conditions. The Meridian Gyrocompass signifies its settled condition by illuminating the green ‘Ready’ lamp.

9. If necessary, you can view the software versions of the main unit and the RCU by pressing both the Selection Up and Selection Down buttons simultaneously. The display will toggle between indications of the main unit software version (with prefix ‘M’) and the RCU software version (with prefix ‘R’). The display will continue to toggle for several seconds after you release the buttons and will then return to the heading indication.

3.3 OPERATING PROCEDUREThe Meridian Gyrocompass will settle automatically after power-on, to provide a true north reference. The system requires only latitude and speed correction, applied manually or from external sources, to perform to the specified accuracy.

Ideally, the Meridian Gyrocompass should accept latitude and speed information from external sources such as a GPS receiver or a speed log, which allow the System to apply corrections automatically.

3.3.1 LATITUDE CORRECTION

1. Press and hold the Latitude selection button.

2. Use the Selection Up and Selection Down buttons to set the local latitude manually. The display will show the latitude in one-degree increments in the range 80°N to 80°S, for example L70N

❐ To select automatic latitude compensation from a GPS receiver, use the Selection Up and Selection Down buttons to scroll beyond 80°N or 80°S until the display shows LGPS.

If there is no valid input available from a GPS receiver, the display will indicate a LGPS alarm after 30 seconds.

3. Release both buttons to set the latitude to the displayed value or to set the gyrocompass to use GPS as the source of automatic latitude correction. The display will indicate the latitude setting and latitude source for several seconds and will then return to the normal heading display.

If you input the operating latitude manually, remember to change the setting when necessary. Note that, in medium latitudes, a 10° error in setting the operating latitude will result in a compass error of approximately 0.5°.


Operation

3.3.2 SPEED CORRECTION1. Press and hold the Speed selection button.

2. Use the Selection Up and Selection Down buttons to set the speed manually in the range zero to 90 knots.

❐ To select automatic speed compensation from a GPS receiver or a speed log, use the selection up button to scroll beyond 90 knots until the display shows SGPS or SLOG.

If there is no valid input available from a speed log or GPS receiver, the display will indicate a SLOG or SGPS alarm after 30 seconds.

3. Release both buttons to set the speed to the displayed value or to set the gyrocompass to use GPS or a speed log as the source of automatic speed correction. The display will indicate the speed setting and speed source for several seconds and will then return to the normal heading display.

If you input the vessel speed manually, remember to set the average vessel speed and to change the setting when necessary. Return the setting to zero on completion of the voyage. For a vessel steaming in a northerly direction, a 5-knot error in speed setting will generate an error of approximately 0.5°.

3.3.3 DG OPERATING MODE

❐ To select Directional Gyro (DG), use the Selection Up and Selection Down buttons to scroll beyond 80°N or 80°S until the display shows DG.

In this mode you can use the Meridian Gyrocompass as a direction indicating instrument all the way up to the poles. If the gyrocompass has settled on north immediately prior to entering the DG mode, it will continue to provide a useful indication of the northerly direction for a period, but will not continue to seek north. The length of time that the direction indication remains valid depends entirely on the gyro drift characteristics.

DG mode will be automatically enabled for latitudes settings greater than 80° applied from the GPS input.The gyrocompass will not north seek while operating in the DG mode.



3.4 ERROR MODESThe Meridian Gyrocompass has three possible Error modes:

1. Loss or corruption of GPS signal2. Loss or corruption of speed log signal3. Gyrocompass system warnings and failures

3.4.1 LOSS OF GPSThis failure mode can occur when you have selected GPS as the source of speed or latitude information and the signal corrupts or becomes lost for a period of 30 seconds. You can recognise this condition by the following indications:

❐ The display shows S.GPS + FAIL for the loss of speed correction information.

❐ The display shows L.GPS + FAIL for the loss of latitude correction information.

❐ The audible alarm will sound.

Press the Alarm button to cancel the audible alarm.

1. The Gyrocompass will use the last valid speed and latitude values.

2. The RCU will continue to show the alarm message until a valid input signal is re-established or a different input source is selected.

3. If the valid input signal has not been established within a period of 30 minutes the audible alarm will be enabled.

3.4.2 LOSS OF SPEED LOGThis failure mode can occur when you have selected speed log as the source of speed information and the signal corrupts or becomes lost for a period of 30 seconds. You can recognise this condition by the following indications:

❐ The display flashes SLOG + FAIL for the loss of selected serial data source information.

❐ The display flashes PLOG + FAIL for the loss of pulsed selected source information.


Press the Alarm button to cancel the alarm.

1. The Gyrocompass will use the last valid speed value.

2. The RCU will continue to show the alarm message until a valid input signal is re-established or a different input source is selected.

If a valid input signal has not been established within a period of 30 minutes the audible alarm will be enabled.


Operation

3.4.3 GYROCOMPASS SYSTEM WARNINGS AND FAILURESThe Meridian Gyrocompass has a built-in system that monitors operation of the gyrocompass. The functions that this system checks are split into two categories.

❐ Warning conditions

❐ Failure conditions

A failure condition will result in the Gyroscope power supply being disabled. Refer to the maintenance section 5 before activating the Power Supply.

Warning ConditionsIf the gyrocompass detects a warning condition, it will use two methods to alert you:

❐ The display shows <Message> + FAIL



Table 3–3: Gyrocompass warning codes

The RCU will continue to show the alarm message until the fault condition has been removed. If the fault condition has not been removed within a period of 30 minutes the audible alarm will be enabled. Refer to sub-section 5.1 which outlines some simple checks that you can make to rectify these fault conditions. If necessary contact TSS (International) Ltd or an approved local service agent for assistance.

<Message>RCU Screen Definition of warning code

dc + fail Internal DC power supply is outside operating limits

ac + fail Internal AC power supply is outside operating limits

rdc + fail Loss of internal timing signals

Temp + fail Over or under operating temperature range

rMT + fail Loss of serial communication link with the RCU



Failure Conditionsf the Meridian Gyrocompass detects a failure condition, it will use six methods to alert you:

❐ The display shows <Message> + FAIL


❐ The ‘Ready’ lamp will extinguish.

❐ The Gyro Fail relay will activate.

❐ Serial output will transmit empty sentences.

❐ Stepper output will transmit an illegal code.


Table 3–4: Gyrocompass failure codes

This failure is considered to be an unrecoverable fault condition, possibly due to a component failure.

To prevent damage to the Gyroscope the power supplies to it will be disabled.

The Gyrocompass will be disabled until it has been reset by the operator. Refer to the maintenance section 5 before activating the Power Switch.

<Message>RCU Screen Definition of failure code

rot + Fail Rate of Turn exceeds 300o/s


Operation

3.5 OPERATING CONSIDERATIONS3.5.1 GENERAL OPERATING CONSIDERATIONS❐ You should leave the Meridian Gyrocompass running continuously. Power-off the

system only during long periods of lay-up, for example during vessel dry-docking. To power-off the Meridian Gyrocompass, press the ‘Power’ button. The heading display will go blank and the front panel lamps will switch off. The gyro rotor will take approximately five minutes to come to rest.

❐ If you intend to leave the system powered-off for an extended period, you should arrange to run the gyrocompass for a period of at least thirty minutes at intervals of six months or less.

❐ The Meridian Gyrocompass has full protection against interruption of its electrical supply. It will re-start and align itself automatically on restoration of electrical power. The heading indication will be accurate when the RCU ‘Ready’ lamp is on.

❐ Monitor the Meridian Gyrocompass performance regularly. When functioning correctly, and provided the correct Speed and Latitude compensations are applied, the heading error in latitudes up to 60° and for speeds up to 25 knots will normally be less than 0.75° regardless of the vessel manoeuvres.

❐ Never move the gyrocompass with the gyro rotor spinning unless you leave the servos operational. Note that the gyro rotor continues to spin for a period of approximately five minutes after you power-off the gyrocompass.



3.5.2 CORRECTIONS FOR SPEED AND LATITUDE❐ Gyrocompass operational accuracy depends, to a large extent, upon accurate

corrections for speed and latitude being applied.

❐ Most users find that the facilities for the automatic application of speed and latitude corrections, via signal inputs from GPS and/or ships log, are a convenient method of applying corrections.

❐ However, users should be aware that if the input signal contains the wrong information, then the wrong corrections will be applied. For instance, it has been noted that some GPS installations, under certain circumstances, will output a “valid” signal with the speed and latitude fields set to all zeros indicating that the vessel is stationary on the equator.

❐ An incorrect input of speed and/or latitude will cause the gyrocompass to indicate an incorrect heading and in the case of extreme errors could cause, in certain circumstances, the gyrocompass to come out of the “Ready mode”.

3.5.3 OPERATING AT EXTREMES OF LATITUDES❐ As latitude increases (north or south) the magnitude of the horizontal component

of the Earth’s rotation rate reduces in proportion to the cosine of latitude. Consequently, the effectiveness of the gyrocompasses north seeking action reduces with increasing latitude.

❐ At latitudes greater than 80o it is recommended that the gyrocompass be operated in the DG (Directional Gyro) mode.

❐ If correction for the effect of latitude on the vertical component of Earth’s rotation is made manually via the RCU, then correction is available to 80o. Thereafter, the directional gyro mode should be manually selected. Errors in the indicated heading will increase with time and increasing latitude above 80o to a maximum of approximately 0.25o /hour. To re-align the gyrocompass, operating latitude must be reduced below 80o and the gyrocompass mode of operation re-selected.

❐ If correction for the effect of latitude on the vertical component of Earth’s rotation is made automatically via a serial data input, then correction is available above 80o and directional gyro mode is automatically selected above this latitude. The compass will still be subject to small inherent drifts while operating in this mode. Reversion to the gyrocompass mode will be made automatically when the serial data latitude input falls below 80o.

3.5.4 OPERATING CONSIDERATIONS FOR VESSEL DYNAMICS

❐ The gyrocompass gravity control gives rise to errors whenever the gyrocompass accelerates or decelerates along the north-south line, that is whenever the northerly speed or course changes. These errors are caused by the inertia of the pendulous element of the gyro, which produces a torque about the horizontal axis and therefore a precession in azimuth. This effect, called ballistic deflection, causes an increase in error during acceleration.

❐ The precession in tilt that arises from the damping component of gravity control is called ballistic tilt. The combined effects of ballistic tilt and ballistic deflection cause the gyrocompass to tilt downwards. Because of the factors that guide the behaviour of a damped gyroscope, the gyro spin axis will return to the settled position by the normal anticlockwise spiral after the acceleration has ceased.


Operation

❐ In the Meridian Gyrocompass, gravity control comes from an accelerometer (pendulum), which generates an electrical signal related to the tilt of the gyro spin axis. This devices has two important design features; it is heavily damped and the range of output is restricted to a small angle.

The use of accelerometer damping by the Meridian Gyrocompass is of prime importance in the reduction of a particularly serious form of ballistic error called inter cardinal rolling error. This type of error occurs most noticeably when the vessel steams on an inter cardinal heading while rolling simultaneously through a significant angle.

If the gyrocompass is installed at some distance above the vessel centre of roll rotation, as is usually the case on commercial vessels, the resulting lateral acceleration components along the east-west and north-south axes of the gyrocompass combine to build an error in the northerly settle point.

If the effect persists for long enough, this error might become as large as several degrees. However, by damping the accelerometer using a time constant several times larger than the vessel rolling period, inter cardinal rolling errors are significantly reduced.

❐ Another form of ballistic error arises from north-south accelerations generated by vessel manoeuvres. Such accelerations can arise from changes in speed and/or course. By limiting the angular output of the accelerometer, the Meridian Gyrocompass reduces the error potential typically to less than one degree.

❐ It is also possible to eliminate acceleration effects by temporarily operating the compass in the DG (Directional Gyro) mode. In this mode gravity control is used for tilt corrections only, so that ballistic effects would cause negligible heading error during short-term acceleration periods. The DG mode can be selected manually from the control panel.

❐ If the special gyro control mode for HSC is selected, the DG mode will be applied automatically in conditions of high accelerations.

This mode of control is recommended for High Speed Craft and other vessels which may be subjected to high accelerations induced by rapid changes of speed or heading.Under these conditions, operation in the standard control mode can cause automatic reversion to the settle mode and consequently larger dynamic heading errors.

❐ The Meridian Gyrocompass complies with all requirements of IMO Resolution A.821(19), Performance Standards for Gyrocompasses for High-Speed Craft.

❐ On earlier versions of the gyrocompass distribution board, the earth connections displayed on Figure 2.3 Gyro Distribution board may not be present for High Speed Craft (HSC).




Technical Data

4 TECHNICAL DATA4.1 SPECIFICATIONS

CAUTIONYou will void the warranty if you operate the gyrocompass outside the environmental conditions detailed in Section 4 and in BS EN 60945.

4.1.1 POWER REQUIREMENTSVoltage 24V DC (acceptable range 18V to 36V DC)

Power consumption 3A at power on, 1.2A continuous (The power supply capacity should exceed 200W)

CAUTIONThe Meridian Gyrocompass should be supplied with power from an SELV source as defined in IEC/EN 60950. The power supply source should be switched and protected by a suitable circuit breaker.

To comply with the requirements of IMO Resolution A.821(19), Performance Standards for Gyrocompasses for High Speed Craft, power to the gyrocompass should be delivered by an uninterruptable power supply.

4.1.2 PERFORMANCE (DEFINITIONS AS IN ISO 8728)Settle point error 0.35° sec latitude

Static error 0.1° sec latitude RMS

Dynamic accuracy 0.3° sec latitude (Scorsby andIntercardinal motion tests)

Settle point repeatability 0.25° sec latitude

Follow up speed 200°/s

Time to settle within 0.7° Less than 45 minutes with a ±30° initial heading offset

4.1.3 COMPENSATIONLatitude compensation range 80°N to 80°S

Speed compensation range 0 to 90 knots

4.1.4 ENVIRONMENTOperating environment EN 60945:1997 designated category

‘weather protected’

Operating temperature 0°C to +45°C (to ISO 8728)–15°C to +55°C (with reduced accuracy)

Storage temperature –25°C to +80°C



4.1.5 SIGNAL INPUTSLatitude IEC 61162 message string via RS232 or

RS422 from GPS

Speed Pulse or contact closure at 100, 200 or 400 per nautical mile from speed log.

IEC 61162 message string at 4800 baud via RS232 or RS422 from GPS or speed log

4.1.6 SIGNAL OUTPUTSS-type heading 1 × step-by-step, 6 steps per degree (TTL

level) update limited to 20o/s to prevent repeater misalignment

Synchro heading 1 × 26V 400Hz (11.8V maximum line-to-line),sector value 360°

Resolver heading 1 × 36V 400Hz (8V maximum per phase),sector value 360°

Analogue rate of turn 1 × rate of turn ±60°/min (±10V) or ±20°/s (±10V)

Serial data outputs 6 × RS23211 × RS422

Serial data formats IEC 61162 updated at 1Hz , 10Hz or 50Hz. Course recorder output (heading, date, time)

Status/alarm 5V TTL power/gyro failureVoltage free power/gyro failure contacts5V TTL system readyVoltage free system ready contacts

4.1.7 DIMENSIONS AND WEIGHTDimensions 344mm (H) × 267mm (W) × 440mm (D)

Weight 15.5kg

RCU size (when mounted externally) 96mm (H) × 192mm (W) × 108mm (D)

RCU weight 0.75 kg

Disposal

WARNINGDo not dispose of by fire or compacting, as toxic fumes, dust or liquids may be released.

❐ Units contain electrical and electronic components which should be disposed of in accordance with current waste disposal practices.

Units may be returned to the manufacturer for safe disposal.

Section 4 Page 2 of 18 © TSS (International) Ltd Issue 3.11 DPN 060070

Technical Data

4.1.8 LISTENER LOAD REQUIREMENTThe gyrocompass presents a listener load of 1.6mA typical at 2V or 3.5mA typical at 5V to all serial data input signals.

Figure 4–1: Listener input circuit

4.1.9 TALKER DRIVE CAPABILITYThe gyrocompass has a talker drive capability of 150mA to ground.

Derived from 26C31 line drivers.

4.1.10 STANDARDSThe Meridian Gyrocompass is designed to meet the requirements of the following:

❐ IMO Resolution A.424 (XI), Performance Standards for Gyrocompasses❐ IMO Resolution A.821 (19), Performance Standards for Gyrocompasses for High

Speed Craft❐ ISO 16328:2001, Gyrocompasses for High Speed Craft❐ BS EN 60945 (2002), General Requirements - Methods of testing and required

test results❐ BS EN ISO 8728:1999, Shipbuilding – Marine Gyrocompasses❐ BS 6217:1981, Graphical Symbols for use on Electrical Equipment❐ CE marking❐ Electromagnetic Compatibility (EMC) Directive❐ The Marine Equipment Directive 96/98/EC

❐ IEC 61162-1:2000(E) Maritime navigation and radio communication equipment and systems - Digital interfaces. Note that IEC 61162-1:2000(E) is closely aligned with NMEA 0183 version 2.30

❐ USCG, United States Coast Guard Type Approval



4.2 DATA FORMATS

Set the DIP switches according to your specific input and output requirements. You will find the instructions to do this in sub-section 2.2.4.

Inputs – Refer to sub-section 4.2.2Acceptable input formats:❐ Latitude information using serial IEC 61162 GNS, RMC, GLL or GGA sentences. If

more than one of these formats is available, the Meridian Gyrocompass makes its selection in the stated preference order. Refer to Figures 4–3, 4–4, 4–5 and 4–6 respectively for a description of these formats.

❐ Datum reference using IEC 61162 DTM sentence. The latitude offset is not used to correct the gyroscope latitude information, however the DTM sentence is re-transmitted.

❐ Speed information using serial IEC 61162 VBW, RMC, VTG or VHW sentences. The sentences can contain speed information using knots and/or km/h. The Meridian Gyrocompass will use the speed in knots if available, in preference to speed in km/h. If more than one of these formats is available, the Meridian Gyrocompass makes its selection in the stated preference order. Refer to Figures 4–8, 4–4, 4–9 and 4–10 respectively for a description of these formats.

❐ If an RMC sentence is used it must contain both speed and latitude information.

❐ TTL-compatible pulsed speed input with a TTL-level signal or contact closure.

Outputs – Refer to sub-section 4.2.3Serial output formats:The Meridian Gyrocompass transmits selected information through RS232 and RS422 serial lines using the IEC 61162 format. The serial transmission can be at either 4800, 9600 or 38400 baud, with updates occurring at 1Hz, 10Hz or 50Hz as defined by the setting of the DIP switches.

Other output formats:

❐ Synchro Heading Output

❐ Resolver Heading Output

❐ Stepper S-code Heading Output

❐ Rate of turn using a bipolar analogue voltage in the range ±10V

The following sub-sections describe each of the formats supported by the Meridian Gyrocompass .


Technical Data

4.2.1 IEC 61162 SERIAL DATA FORMATS – GENERAL INFORMATIONThe Meridian Gyrocompass accepts and transmits asynchronous serial data using 8 data bits, one stop bit and no parity through RS232 and RS422 transmit-only lines. The data bits occur in each packet with the least significant bit first. The most significant bit of the 8-bit character will always be zero.

Figure 4–2: Serial data format

All data is interpreted as ASCII characters that form IEC 61162 sentences split into individual fields. All fields, including null fields, are separated by commas.

The IEC 61162 format requires a checksum – if included, the checksum occurs as an additional field immediately before the carriage return line-feed characters. It consists of an asterisk (*) followed by a checksum derived by exclusive OR-ing the eight data bits of each valid character preceding the asterisk, but excluding the $ symbol, in the sentence. The absolute value of the checksum is transmitted in ASCII characters representing the value in HEX. For circumstances where the Meridian Gyrocompass retransmits serial data using the same IEC 61162 sentence format supplied by an external source, it will recalculate any checksum and insert the new value into the output sentence.

IEC 61162 sentences are usually transmitted once per second, however you can set a DIP switch to select a transmission update rate of either 1, 10 or 50 per second. The outputs are grouped into two channels that can be set independently. The All Data output option of heading, latitude, speed, datum, rate of turn and time sentences will always be transmitted at 1Hz.



4.2.2 INPUTS4.2.2.1 IEC 61162 INPUT SIGNALS

The Meridian Gyrocompass will accept sentences in both the IEC 61162-1:2000(E) and NMEA 0183 version 2.1 data formats.

In the following descriptions of input sentences, the Meridian Gyrocompass uses the data fields marked ‘XXX’ in the IEC 61162 sentence. The system does not use the fields marked ‘???’ and their descriptions are included here for completeness only. The gyrocompass will recognise the arriving sentence format and will extract the required data from it automatically.

GPS Interface (see Table 2-3 for connection details)The Meridian Gyrocompass can accept speed, latitude, date and time inputs at the GPS interface in IEC 61162 format using GNS, RMC, GLL, GGA, VTG, VHW and ZDA sentences.

Figure 4–3: IEC 61162 GNS input sentence structure

Figure 4–4: IEC 61162 RMC input sentence structure

$??GNS,??????.??,XXXX.XX,X,?????.??,?,X--X,??,?.?,?.?, [CRLF]?.?,?.?,?.?*??

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rG

NS

Sfix

data

UT

Cof

posi

tion

Nor

th/S

outh

Latit

ude

(ddm

m.m

m)

Long

titud

e

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Eas

t/Wes

t

Diff

eren

tial r

efer

ence

stat

ion

ID

Che

cksu

mfie

ld

Age

ofdi

ffere

ntia

l dat

a

Geo

idal

sepe

ratio

n,m

Ant

enna

altit

ude,

m, r

e:m

ean-

sea-

leve

l (ge

oid)

HD

OP

Tota

l num

ber

ofsa

telli

tes

inus

e,0-

99

Mod

eIn

dica

tor

$??RMC,??????.??,X,XXXX.XX,X,?????.??,?,X.X,?.?,??????,?.?,?,X[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rR

ecom

men

ded

Min

GP

Sda

ta

UT

Cof

posi

tion

(hhm

mss

.ss)

Latit

ude

(ddm

m.m

m

Mne

mon

icfo

rN

orth

orS

outh

Sta

tus,

A=

valid

, V=

Nav

. Rec

eive

rw

arni

ng

Long

itude

(ddd

mm

.mm

)

Mne

mon

icfo

rE

ast o

rW

est

Mag

netic

varia

tion

indi

cato

rea

stor

Wes

t

Gro

und

spee

din

knot

s

Mag

netic

varia

tion

inde

gree

s

Cou

rse

over

grou

ndin

degr

ees

Dat

eof

fix

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Mod

eIn

dica

tor


Technical Data

Figure 4–5: IEC 61162 GLL input sentence structure

Figure 4–6: IEC 61162 GGA input sentence structure

Figure 4–7: IEC 61162 DTM input sentence structure

$??GLL,XXXX.XX,X,?????.??,?,??????.??,X,X[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rge

ogra

phic

alLa

t and

Lon

Latit

ude

(ddm

m.m

m)

Long

itude

(ddd

mm

.mm

)

Mne

mon

icfo

rN

orth

orS

outh

Mne

mon

icfo

rE

ast o

rW

est

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

UT

Cof

posi

tion

(hhm

mss

.ss)

Sta

tus

Mod

eIn

dica

tor

$??GGA,??????.??,XXXX.XX,X,?????.??,?,X,??,?.?,?.?,?,?.?,?,?.?,????[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rG

PS

fixda

ta

UT

Cof

posi

tion

(hhm

mss

.ss)

Latit

ude

(ddm

m.m

m

Mne

mon

icfo

rN

orth

orS

outh

Long

itude

(ddd

mm

.mm

)

Mne

mon

icfo

rE

ast o

rW

est

GP

Squ

ality

indi

cato

r

Num

ber

ofsa

telli

tes

inus

e(0

0-

12)

Hor

izon

tal d

ilutio

nof

prec

isio

n

Ant

enna

altit

ude

rela

tive

tom

ean

sea

leve

l

Mne

mon

icfo

rm

etre

s

Mne

mon

icfo

rm

etre

s

Geo

idal

sepa

ratio

n

Age

ofdi

ffere

ntia

l GP

Sda

ta

Diff

eren

tial r

efer

ence

stat

ion

(000

0-

1023

)

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

$??DTM,???,?,?.?,?,?.?,?,?.?,???*hh[CRLF]

Talk

erid

entif

ier

Mne

mon

icfo

rD

atum

refe

renc

e

Loca

l dat

umsu

bdiv

isio

nco

de

Latit

ude

offs

et

Loca

l dat

um

Ref

eren

ceda

tum

Nor

th/S

outh

Che

cksu

mfie

ld

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Long

itude

offs

et

Eas

t/Wes

t

Alti

tude

offs

et, m



Figure 4–8: IEC 61162 VBW input sentence structure

Figure 4–9: IEC 61162 VTG input sentence structure

Figure 4–10: IEC 61162 VHW input sentence structure

$??VBW,?.?,?.?,?,X.X,?.?,X,?.?,?,?.?,?*hh[CRLF]Ta

lker

iden

tifie

r(a

nych

arac

ters

)

Mne

mon

icfo

rD

ual g

roun

d/w

ater

spee

d

Long

itudi

nal w

ater

spee

d,kn

ots

Sta

tus:

wat

ersp

eed,

A=

valid

, V=

not v

alid

Tra

nsve

rse

wat

ersp

eed,

knot

s

Long

itudi

nal g

roun

dsp

eed,

knot

s

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Tra

nsve

rse

grou

ndsp

eed,

knot

s

Sta

tus:

ster

ngr

ound

spee

d,A

=va

lid, V

=no

t val

id

Che

cksu

mfie

ld

Sta

tus:

grou

ndsp

eed,

A=

valid

, V=

not v

alid

Ste

rntr

ansv

erse

wat

ersp

eed,

knot

s

Sta

tus:

ster

nw

ater

spee

d,A

=va

lid, V

=no

t val

id

Ste

rntr

ansv

erse

grou

ndsp

eed,

knot

s

$??VTG,?.?,?,?.?,?,X.X,X,XX.X,X,X[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rgr

ound

cour

sean

dsp

eed

Mne

mon

icfo

rT

rue

head

ing

Mne

mon

icfo

rM

agne

tiche

adin

g

Cou

rse

inde

gree

san

dte

nths

Mne

mon

icfo

rkn

ots

Spe

edin

knot

s

Spe

edin

km/h

Mne

mon

icfo

rkm

/h

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Cou

rse

inde

gree

san

dte

nths

Mod

ein

dica

tor


Technical Data

Figure 4–11: IEC 61162 ZDA input sentence structure

Log Interface (see Table 2-3 for connection details)The Meridian Gyrocompass can accept speed inputs at the Log interface in IEC 61162 format using VBW, VTG and VHW sentences only.

Figure 4–12: IEC 61162 VBW input sentence structure

Figure 4–13: IEC 61162 VTG input sentence structure

$??ZDA,XXXXXX.XX,XX,XX,XXXX,??,??[CRLF]Ta

lker

iden

tifie

r(a

nych

arac

ters

)

Mne

mon

icfo

rT

ime

and

Dat

e

Day

ofm

onth

(01

to31

)

Mon

thof

year

(01

to12

)

UT

C(h

hmm

ss.s

s)

Loca

l zon

eho

urs

(00

to±

13)

Yea

r

Loca

l zon

em

inut

es(0

0to

+59

)

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

$??VBW,?.?,?.?,?,X.X,?.?,X,?.?,?,?.?,?*hh[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rD

ual g

roun

d/w

ater

spee

d

Long

itudi

nal w

ater

spee

d,kn

ots

Sta

tus:

wat

ersp

eed,

A=

valid

, V=

not v

alid

Tra

nsve

rse

wat

ersp

eed,

knot

s

Long

itudi

nal g

roun

dsp

eed,

knot

s

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Tra

nsve

rse

grou

ndsp

eed,

knot

s

Sta

tus:

ster

ngr

ound

spee

d,A

=va

lid, V

=no

t val

id

Che

cksu

mfie

ld

Sta

tus:

grou

ndsp

eed,

A=

valid

, V=

not v

alid

Ste

rntr

ansv

erse

wat

ersp

eed,

knot

s

Sta

tus:

ster

nw

ater

spee

d,A

=va

lid, V

=no

t val

id

Ste

rntr

ansv

erse

grou

ndsp

eed,

knot

s

$??VTG,?.?,?,?.?,?,X.X,X,XX.X,X,X[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rgr

ound

cour

sean

dsp

eed

Mne

mon

icfo

rT

rue

head

ing

Mne

mon

icfo

rM

agne

tiche

adin

g

Cou

rse

inde

gree

san

dte

nths

Mne

mon

icfo

rkn

ots

Spe

edin

knot

s

Spe

edin

km/h

Mne

mon

icfo

rkm

/h

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Cou

rse

inde

gree

san

dte

nths

Mod

ein

dica

tor



Figure 4–14: IEC 61162 VHW input sentence structure

4.2.2.2 PULSED INPUT

The Meridian Gyrocompass can accept a speed input as a series of pulses or contact closures occurring at a frequency of 100, 200 or 400 per nautical mile as selected by a DIP switch. Refer to Table 2-5. The gyrocompass determines the vessel speed by reference against the microprocessor timing circuits. The speed pulses do not need to have a particular mark/space ratio, although they should be TTL-level. Contact closures should be of good quality and electrically floating.


Technical Data

4.2.3 OUTPUTS4.2.3.1 IEC 61162 OUTPUT SIGNALS

The Meridian Gyrocompass can output serial data through RS232 and RS422 transmit-only serial lines using the IEC 61162-1:2000(E) format. The output of each channel can be set independently, using DIP switches, to contain either:

1. Heading - as described below, OR

2. Heading and Rate of turn - as described below, OR

3. Rate of turn only - as described below, OR

4. All data - all information described below, transmitted in the order stated

❐ Heading information is transmitted using an HDT format sentence. The resolution of the heading information can be set to one or two decimal places at the DIP switches. Refer to Figures 4–15 for a description of this output format.

❐ Rate of turn information is transmitted using a ROT format sentence. Refer to Figure 4–16 for a description of this output format.

❐ Speed information is transmitted using a VTG format sentence if the gyrocompass is configured for manual or a pulsed speed log input. The VTG sentence also has provision for Heading and this is inserted at a resolution as set by the DIP switches. Refer to Figure 4–18 for a description of this output format. If the gyrocompass is configured for a GPS speed input and the speed information arrives at the gyrocompass in either VBW, RMC, VTG or VHW format, then the gyrocompass will retransmit the received format modifying the sentence to include the HE talker identifier. Refer to Figures 4–17, 4–21, 4–18, and 4–19 for a description of these output formats.

❐ Datum reference is retransmitted if the DTM sentence is received on the GPS input. The gyrocompass will re-transmit the received sentence modifying it to include the HE talker identifier. Refer to Figure 4–24 for a description of this output format.

❐ Latitude information is transmitted using a GLL format sentence if the gyrocompass is configured for manual latitude input. Refer to Figure 4–22 for a description of this output format. If the gyrocompass is configured for a GPS latitude input and the latitude information arrives at the gyrocompass in either GNS, RMC, GLL, or GGA format, then the gyrocompass will retransmit the received sentence modifying the sentence to include the HE talker identifier. Refer to Figures 4–20, 4–21, 4–22 and 4–23 for a description of these output formats.

❐ Date and time information is transmitted using a ZDA format sentence. The gyrocompass will transmit the ZDA sentence including the HE talker identifier. If this information is received from a GPS source, all fields will be retransmitted. If there is no valid date and time from an external source, the gyrocompass will transmit the ZDA sentence with empty data fields. Refer to Figure 4–25 for a description of this output format.

If the All Data output format is selected at the DIP switches, the transmission update rate for that channel will be at 1Hz regardless of the setting of the channel update rate.The All Data output is not suitable for HSC applications.



In the following descriptions of output sentences, the gyrocompass sets the contents of fields marked XXX and leaves unchanged the fields marked ???

Figure 4–15: IEC 61162 HDT output sentence structure

Figure 4–16: IEC 61162 ROT output sentence structure

Figure 4–17: IEC 61162 VBW output sentence structure$HEVBW,?.?,?.?,?,?.?,?.?,?,?.?,?,?.?,?*hh[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rD

ual g

roun

d/w

ater

spee

d

Long

itudi

nal w

ater

spee

d,kn

ots

Sta

tus:

wat

ersp

eed,

A=

valid

, V=

not v

alid

Tra

nsve

rse

wat

ersp

eed,

knot

s

Long

itudi

nal g

roun

dsp

eed,

knot

s

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Tra

nsve

rse

grou

ndsp

eed,

knot

s

Sta

tus:

ster

ngr

ound

spee

d,A

=va

lid, V

=no

t val

id

Che

cksu

mfie

ld

Sta

tus:

grou

ndsp

eed,

A=

valid

, V=

not v

alid

Ste

rntr

ansv

erse

wat

ersp

eed,

knot

s

Sta

tus:

ster

nw

ater

spee

d,A

=va

lid, V

=no

t val

id

Ste

rntr

ansv

erse

grou

ndsp

eed,

knot

s


Technical Data

Figure 4–18: IEC 61162 VTG output sentence structure

In GPS mode, only the talker identifier is changedIn manual mode, the magnetic course fields are empty.

Figure 4–19: IEC 61162 VHW output sentence structure

Figure 4–20: IEC 61162 GNS output sentence structure

$HEVHW,???.?,?,???.?,?,??.?,?,??.?,?[CRLF]

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rve

ctor

head

ing

and

wat

ersp

eed

Mne

mon

icfo

rT

rue

head

ing

Mne

mon

icfo

rM

agne

tiche

adin

g

Hea

ding

inde

gree

san

dte

nths

Mne

mon

icfo

rkn

ots

Spe

edin

knot

s

Spe

edin

km/h

Mne

mon

icfo

rkm

/h

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Hea

ding

inde

gree

san

dte

nths

$HEGNS,??????.??,????.??,?,?????.??,?,????,??,?.?,?.?, [CRLF]?.?,?.?,?.?*??

Talk

erid

entif

ier

(any

char

acte

rs)

Mne

mon

icfo

rG

NS

Sfix

data

UT

Cof

posi

tion

Nor

th/S

outh

Latit

ude

(ddm

m.m

m)

Long

titud

e

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Eas

t/Wes

t

Diff

eren

tial r

efer

ence

stat

ion

ID

Che

cksu

mfie

ld

Age

ofdi

ffere

ntia

l dat

a

Geo

idal

sepe

ratio

n,m

Ant

enna

altit

ude,

m, r

e:m

ean-

sea-

leve

l (ge

oid)

HD

OP

Tota

l num

ber

ofsa

telli

tes

inus

e,0-

99

Mod

eIn

dica

tor



Figure 4–21: IEC 61162 RMC output sentence structure

Figure 4–22: IEC 61162 GLL output sentence structure

In GPS mode, only the talker identifier is changedIn manual mode, the longitude and UTC fields are empty.

Figure 4–23: IEC 61162 GGA output sentence structure


Technical Data

Figure 4–24: IEC 61162 DTM output sentence structure

Figure 4–25: IEC 61162 ZDA output sentence structure

4.2.4 IEC 61162 SENTENCE WITH CHECKSUMWhen the checksum is to be sent with any of the above IEC 61162 sentences, it appears as an extra field inserted before the carriage return character as shown by example in Figure 4-25.

Figure 4–26: IEC 61162 sentence with optional checksum

The checksum consists of an asterisk followed by the checksum calculated by exclusive OR-ing the eight data bits of each valid character preceding the asterisk, but excluding the ‘$’ symbol, in the sentence. The Meridian Gyrocompass transmits the absolute value of the checksum in ASCII characters representing the value in HEX.

$HEDTM,???,?,?.?,?,?.?,?,?.?,???*hh[CRLF]Ta

lker

iden

tifie

r

Mne

mon

icfo

rD

atum

refe

renc

e

Loca

l dat

umsu

bdiv

isio

nco

de

Latit

ude

offs

et

Loca

l dat

um

Ref

eren

ceda

tum

Nor

th/S

outh

Che

cksu

mfie

ld

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter

Long

itude

offs

et

Eas

t/Wes

t

Alti

tude

offs

et, m

$HEZDA,??????.??,??,??,????,??,??[CRLF]

Talk

erid

entif

ier

Mne

mon

icfo

rT

ime

and

Dat

e

Day

ofm

onth

(01

to31

)

Mon

thof

year

(01

to12

)

UT

C(h

hmm

ss.s

s)

Loca

l zon

eho

urs

(00

to±

13)

Yea

r

Loca

l zon

em

inut

es(0

0to

+59

)

Car

riage

retu

rnLi

ne-f

eed

char

acte

rs

Sta

rtch

arac

ter



4.2.5 OTHER OUTPUT FORMATS4.2.5.1 COURSE RECORDER OUTPUT

The following ASCII data shall be transmitted on the Course Recorder Output every minute, in a suitable format to be output on an 80 column line printer.

359.99 True Lat 52 N Spd 10 Kts UTC 13:34:01 01/01/2001

❐ Date and time will only be output if a valid ZDA sentence is available on the GPS input.

4.2.5.2 SYNCHRO OUTPUT

The synchro heading output is available continuously at TB2 on the Distribution Board while the gyrocompass is powered-on – refer to Table 2-4 for connector details. The output is at 11.8V maximum line-to-line voltage derived electrically from a 1:1 resolver driven directly by the gyrocompass azimuth gimbal. The synchro reference voltage is a nominal 26V 400Hz supply generated internally.

Electrical loading specification:

❐ Not less than 5k between any two S lines.

❐ Not less than 1k between the two R lines.

4.2.5.3 RESOLVER OUTPUT

The resolver heading output is available continuously at TB2 on the Distribution Board while the gyrocompass is powered-on – refer to Table 2-4 for connection details. The output is at 8V maximum voltage per phase signal from a 1:1 resolver driven directly by the gyrocompass azimuth gimbal. The resolver reference voltage, which is generated internally, can be set nominal 36V 400Hz or 10V 400Hz by jumper JP30 on PCB929066. The factory default setting is 36V 400Hz.

The resolver sine and cosine outputs must be electrically isolated from each other. Contact the TSS (International) Ltd Service Department for technical advice if necessary.

Electrical loading specification:

❐ Not less than 5k between any two S lines.

❐ Not less than 1k between the two R lines.

Table 4–1: Course Recorder Output Sentences

Heading 999.99

Latitude 99

Hemisphere N or S

Speed Kts 99

Time hh:mm:ss

Date dd/mm/yy


Technical Data

4.2.5.4 STEPPER S-CODE

The stepper S-code output is available continuously at TB2 on the Distribution Board while the gyrocompass is powered-on – refer to Table 2-4 for connection details.

The stepper output is a TTL compatible S-encoded signal with a 10mA sink capacity.

4.2.5.5 RATE OF TURN

The ROT output is calculated by the internal processor updated at 10Hz and made available continuously at TB3 on the Distribution Board while the gyrocompass is powered-on – refer to Table 2-4 for connection details.

The ROT output is a bipolar analogue voltage in the range ±10V to represent rates of turn from –60° to +60° per minute or –20° to +20° per second by DIP-switches. Refer to Table 2-4 . Positive rates of turn are to starboard.




Maintenance

5 MAINTENANCEWARNING

There is a danger of serious injury from voltages inside the Meridian Gyrocompass . Do not remove the gyrocompass cover unless you have the necessary skills and experience to perform maintenance work on a system of this nature. Always power-off the system before you remove the cover for maintenance work.Observe all local safety regulations as you work on the equipment. Reconnect the safety grounding straps and refit all safety covers to the equipment before you power-on the system.

CAUTIONPerform maintenance instructions only if you have the skills and experience required, and only when necessary. Inappropriate tampering with the internal controls and components of the gyrocompass can lead to damage or serious performance degradation.NEVER open the gyrocompass cover or make any adjustments inside the gyrocompass unless you are entirely confident in your actions.

There is very little need for user maintenance on the Meridian Gyrocompass and you should never need to remove the covers.

The following sub-sections explain some very basic procedures that you may attempt if you suspect the system has developed a fault. If you are in any doubt, contact TSS (International) Ltd for advice and technical assistance before you begin any maintenance work on the system.

5.1 Built-in Test Equipment Page 1The Meridian Gyrocompass performs a self-test routine during the initialisation sequence and monitors its status continually during normal operation. Any deviation from normal operation appears as an error message, with the cause declared as a message on the four-character display panel. This sub-section explains some very basic tests and adjustments that you may perform on the system.

5.2 Test Connector Page 3There is a 60-way test connector that allows you to measure critical voltages and signals.

5.1 BUILT-IN TEST EQUIPMENTA Test Box (TSS (International) Ltd part number 929220) is available to facilitate connection to the 60-way connector.

In Subsection 3.4.3 there is a list of warning codes and failure codes delivered by the built-in test equipment if it detects a fault in the gyrocompass. In these conditions, the four-character display will show <Message> + FAIL



If the built in test equipment detects a fault, use the following table to investigate the cause. You can measure the voltages and signals on the pins of the 60-way test connector (refer to Table 5.2 for details of the test connector).

5.1.1 AZIMUTH DRIFT ADJUSTMENTYou may use the following procedure to measure and, if necessary, adjust the azimuth drift:

1. Ensure that the gyrocompass is static and is operating in DG mode with the Speed input set manually to zero and the Latitude set to local latitude. Refer to sub-sections 3.3.1 to set the latitude, 3.3.2 to set the speed and 3.3.3 to set DG mode.

2. Note the initial heading (H1) shown on the RCU display.

3. Wait for one hour and then note the heading (H2) shown on the RCU display.

4. Calculate the azimuth drift rate (H2 – H1) degrees per hour.

5. Use a digital meter set to measure DC volts and monitor the Tilt Bias between pins 30 and 51 of the 60-way test connector (with the positive test lead on pin 30).

Table 5–1: Test Measurements

Failure Code Measure Expected value Signal source

dc+failFailure of DC power supply

DC supply42 (+ve) to 4344 (+ve) to 4317 (+ve) to 1850 (+ve) to 5152 (+ve) to 5145 (+ve) to 18

18V DC to 36V DC+24V DC ±0.5V DC–24V DC ±0.5V DC+5V DC ±0.1V DC+15V DC ±0.2V DC–15V DC ±0.2V DC+5V DC (+0.2V/–0.7V DC)

Ship’s mains/PSUDC/DC PSUDC/DC PSUDC/DC PSUControl Board analogueControl Board analogueControl Board analogue

ac+failFailure of AC power supply

19 to 4320 to 4321 to 4358 to 4357 (+ve) to 18

2.5V AC ±0.125V AC @ 19.2kHz14V AC ±1V @ 480Hz (18V AC ±1.5V at start (1-min))14V AC ±1V @ 480Hz (18V AC ±1.5V at start (1-min))12V AC ±0.2V @ 400Hz+5V DC ±0.2V DC

Control Board analogueControl Board analogueControl Board analogueControl Board analogueControl Board analogue

rdc+FailFailure of synchro-to-digital converter

58 to 4353 (+ve) to 5154 (+ve) to 51

12V AC ±0.2V @ 400Hz(5.4V DC ±0.5V DC) × sin heading(5.4V DC ±0.5V DC) × cos heading

Control Board analogueControl Board analogueControl Board analogue

rMT+failLoss of RCU communication

50 way IDC Cable (Part Number B929157)+ 5V DC Power Supply5 way Cable Loom (Part Number B929161)

ROT+failRate of turn exceed limit

>300o/s Check Gyro connection to the analogue PCB

Temp+failTemperature exceeds operat-ing range

<-20oC>+60oC

Check operating environment and ventilation


Maintenance

6. Adjust the Tilt Bias potentiometer RV7 by 400mV × drift rate (°/hr). You must turn the potentiometer anticlockwise to compensate for azimuth drift towards higher readings. Figure 2–4 shows the location of the Tilt Bias potentiometer.

7. Repeat steps 2 to 6 above until the calculated drift rate is less than 0.2°/hr.

8. Refer to sub-section 3.3.3 to deselect the DG mode.

5.1.2 AZIMUTH BIAS ADJUSTMENTYou may use the following procedure to eliminate small angles of heading error from the Meridian Gyrocompass . Measure and, if necessary, adjust for azimuth drift as described in sub-section 5.1.1 above before you adjust the azimuth bias.

Take care when you adjust azimuth bias – make only small adjustments each time and then allow the gyrocompass to settle for three hours before you make any further adjustments. Note the original position of the azimuth bias control before you start so that you can restore the starting condition if necessary.

1. Use a digital meter set to measure DC volts and monitor the Azimuth Bias between pins 29 and 51 of the 60-way test connector (with the positive test lead on pin 29).

2. Adjust the Azimuth Bias potentiometer RV9 to cause a change in the azimuth bias voltage that will produce the necessary change in compass heading. Figure 2–4 shows the location of the Azimuth Bias potentiometer.

3. Turn the Azimuth Bias potentiometer anticlockwise to cause the heading to change towards a lower reading. A 60mV DC change in Azimuth Bias will produce a 1-degree change in heading.

5.2 TEST CONNECTORThere is a sixty-way test connector accessible behind the removable panel on the top of the gyrocompass cover. Release and remove the securing screws and lift off the panel to see the two DIP switches and the test connector. A test box (TSS part number 929220) is available to facilitate connection to the 60-way test connector. Table 5–2: Sixty-way Test Connector

Pin Name Function

1 S1_SYNCHRO 11.8V RMS 400Hz synchro S1 phase

2 S2_SYNCHRO_RES 11.8V RMS 400Hz synchro S2 phase

3 S3_SYNCHRO_RES 11.8V RMS 400Hz synchro S3 phase

4 26V_SYNCHRO_R1 26V RMS 400Hz synchro R1 reference

5 0V_SYNCHRO_RES 26V RMS 400Hz synchro R1 reference

6 GA_MODE Directional gyro mode control (+5V logic)

7 GC_MODE Gyrocompass mode control (+5V logic)

8 AA_MODE Auto alignment mode control (+5V logic)

9 LAT_NS Latitude north selection control (+5V logic)

10 SERVO_EN Tilt and azimuth servo enable control (+5V logic)



11 WHEEL_BOOST Gyro wheel supply boost control (+5V logic)

12 LOG_OK Speed log OK flag (+5V logic)

13 GPS_OK GPS OK flag (+5V logic)

14 SYS_FAIL System fail flag (+5V logic)

15 GYRO_RDY Gyrocompass ready flag (+5V logic)

16 PREPARE Prepare mode (servo nulling) (+5V logic)

17 VCC 5V DC supply

18 GND 5V DC supply return

19 PICK_OFF_SUPPLY_1 Gyro pick off supply 2.5V RMS 19.2kHz sine wave

20 WHEEL_SUPPLY_1 Gyro wheel supply 0 phase 10V (18V) RMS 480Hz square wave

21 WHEEL_SUPPLY_2 Gyro wheel supply 90 phase 10V (18V) RMS 480Hz square wave

22 PWMO Compass card illumination PWM control 5V 85Hz square wave

23 ACC Gravity control signal ±150mV DC/min T=60s

24 10V 10V DC positive voltage reference

25 _10V 10V DC negative voltage reference

26 LAT_TORQ Latitude torquing input signal (–10 sin[latitude])V DC

27 SPEED_N_TORQ Speed N torque i/p signal (7.3e–3 × speed(kts) × cos[heading])

28 SPEED_E_TORQ Speed E torque i/p signal (–8.5e–3 × speed(kts) × sin[heading] × tan[latitude]V DC

29 AZ_BIAS Bias adj. to azimuth torquer ±2.2V DC (60mV/deg heading)

30 TILT_BIAS Bias adj. to tilt torquer ±2.2V DC (400mV/deg/hour heading)

31 TILT_TEMP Bias adj. to tilt torquer proportional to temperature (400mV/deg/hr heading)

32 AZ_TEMP Bias adj. to azimuth torquer proportional to temperature (60mV/deg/hr heading)

33 T Temperature ref (non-inverted) from gimbal thermistor (DC V proportional to temp)

34 T_ Temperature ref (inverted) from gimbal thermistor (DC V proportional to temp)

35 TILT_TORQUER_LO Tilt torquer signal 0.013V DC/mA (torquer scale factor 10°/hr/mA)

36 AZ_TORQUER_LO Azimuth torquer signal 0.006V DC/mA (torquer scale factor 10°/hr/mA)

37 TILT_PICK_OFF_DC Demodulated gyroscope tilt pick-off signal

38 AZ_PICK_OFF_DC Demodulated gyroscope azimuth pick-off signal

39 18V10V Gyro wheel positive supply

40 -18V10V Gyro wheel negative supply

41 UP_DOWN Accelerometer - Slave comparator

42 24V 24V DC positive supply

Table 5–2: Sixty-way Test Connector

Pin Name Function


Maintenance

43 0V Supply return for ±24V DC

44 –24V 24V DC negative supply

45 PSU_LO PSU (+5V DC and ±15V DC) under voltage flag (+5V DC logic)

46 NOT USED

47 ACC_COS_LAT Latitude weighted gravity control signal (150/cos latitude)mV DC/min

48 SLAVE Slave accelerometer gravity control signal (10mV/bit)

49 ROT Analogue rate of turn output (0.5V DC/deg/s (10V DC max) CW +ve; ACW –ve

50 15V 15V DC positive supply

51 0Va Supply return for ±15V DC

52 –15V 15V DC negative supply

53 SIN_DC Analogue voltage proportional to sin(heading) (±0.1V DC/deg heading)

54 COS_DC Analogue voltage proportional to cos(heading) (±0.1V DC/deg heading)

55 RS232_RX_TEST RS232 receive port reserved for product testing

56 RS232_TX_TEST RS232 transmit port diagnostic output sentence

57 AC_OK AC supply (19kHz, 480Hz and 400Hz) OK flag (+5V DC logic)

58 400_REF_HI Reference supply 12V RMS 400Hz

59 AZ_MOTOR_HI Drive to azimuth follow-up DC servo motor

60 TILT_MOTOR_HI Drive to tilt follow-up DC servo motor

Table 5–2: Sixty-way Test Connector

Pin Name Function



5.3 DIAGNOSTIC OUTPUT SENTENCEAn ASCII character diagnostic sentence, delivered via RS232 line standard at 4800 baud, is available at test connector PL6/56-18(GND).

Note that this sentence information is only valid for gyrocompasses fitted with software of the following version or higher: BPR 113 (main) and BPR 114 (RCU).

It may be useful to monitor this sentence when communicating with TSS (International) Ltd for technical assistance. The sentence string may be read using "Microsoft Terminal" or similar ASCII reader.

Sentence StructureGyro Control 1 = slave accelerometer (new hardware)

S = special gyro control mode for HSC (for gyrocompasseswith serial numbers later than 3500)R = real accelerometer (original hardware)A = special applications only (original hardware)

Mode L = levelA = alignmentC = compassD = DG

Status F = failR = readyS = settle

Latitude (degrees) xxHemisphere N or SSpeed (knots) xxAverage Accelerometer (bits) Paxxx

ADC 1 (bits) rxxxADC 2 (bits) hxxxADC 3 (bits) txxxADC 4 (bits) axxxADC 5 (bits) Txxx

DAC 1a (bits) xxxDAC 1b (bits) xxxDAC 2a (bits) xxxDAC 2b (bits) xxxDAC 3a (bits) xxxDAC 3b (bits) xxxHeading (degrees) $HEHDT,xxx.xx,T

Sentence ExampleR CR 51N 06 Pa128r128h128 t128a128 T096 160 198 000 000 128 128 $HEHDT,000.00,T

During start-up, the Mode and Status characters will change in the following sequence:

1. LS for about 4 minutes2. AS for 25 - 60 minutes (dependent upon initial heading misalignment)3. CR in READY mode and functioningEnsure that the Latitude and Speed values in the sentence correspond with the automatic or manually set values applied to the gyrocompass. Ensure that the Heading value in the sentence is correct.


Maintenance

Figure 5–1: System Block Diagram

GIM

BA

LA

SS

Y

DIS

PLA

YB

OA

RD

CO

NT

RO

LB

OA

RD

RE

MO

TE

DIS

TR

IBU

TIO

N

BO

AR

D

CO

NT

RO

LB

OA

RD

DIG

ITA

LA

NA

LO

GU

E

CO

NT

RO

LB

OA

RD

TE

ST

CO

NN

EC

TO

R

DC

/DC

PS

U

FIL

TE

RS

#1

&#2

24V

d.c

.

Tilt

Moto

r

Azim

uth

Moto

r

Tilt

Pic

koff

Azim

uth

Pic

koff

Tilt

Torq

uer

Azim

uth

Torq

uer

(vert

icalsensor)

(tem

psensor)

Resolv

er

Illu

min

atio

n24-0

-24V

d.c

.

5V

d.c

.

An

alo

gu

eC

on

tro

lS

ign

als

Azim

uth

To

rqu

er

Co

ntr

olS

ign

al

Tilt

Torq

uer

Contr

olS

ignal

Tem

pS

ensor

Sig

nal

Acce

lero

me

ter

Sig

na

l

Re

so

lve

rH

ea

din

gS

ign

al(s

in/c

os)

Tilt

Pic

koff

Sig

nal(a

.c.)

Azim

uth

Pic

koff

Sig

nal(a

.c.)

Tilt

Moto

rD

rive

Sig

nal

Azim

uth

Mo

tor

Drive

Sig

na

l

Illu

min

atio

nC

on

tro

l

Acce

lero

me

ter

Sig

na

l(h

igh

ga

in)

Tem

pS

ensor

Sig

nal

Re

so

lve

rH

ea

din

gS

ign

al(d

.c.)

Tilt

P.O

.S

ignal(d

.c.)

Azim

uth

P.O

.S

ignal(d

.c.)

Analo

gue

Headin

gS

ignals

SerialO

utp

ut

Sig

nals

Serial&

Dig

italIn

putS

ignals

Rem

ote

ON

/OF

FC

ontr

ol

Gyro

Sp

inM

oto

rS

up

ply

Gyro

Sp

inM

oto

r

Rem

ote

ON

/OF

F

Com

munic

ations

Display Driver Signals

Input

Sig

nals

Outp

ut

Sig

nals

5V

d.c

.

Com

munic

ations

929083

929074

929066

929033

929078

929049

929045

Pow

er

Pow

er

Switch I/Ps

Acce

lero

me

ter

Therm

isto

r



Figure 5–2: Gimbal Assembly Functional DiagramZ

H

X

Y

N-S

H

Resolv

er

40

0H

zS

inH

Co

sH

Azim

uth

Torq

uer

Co

ntr

olS

ign

al

Sig

na

l(A

cc)

Acce

lero

me

ter

Co

ntr

olS

ign

al

Tilt

Torq

uer

Moto

r

Azim

uth

Dri

ve

Sig

na

l

Tilt

Moto

r

Dri

ve

Sig

na

l

Te

mp

era

ture

Se

nso

rS

ign

al

Azim

uth

Pic

koff

Sig

na

l

Tilt

Pic

ko

ff

Sig

na

l

1

2

8

5

9

67

3

4

10

1.D

am

pe

r

2.G

yro

sp

inm

oto

r

3.

Tilt

torq

uer

4.

Azim

uth

torq

ue

r

5.

Acce

lero

me

ter

6.

Azim

uth

pic

ko

ff

7.

Tilt

pic

koff

8.T

he

rmis

tor

9.

Tilt

moto

r

10

.A

zim

uth

mo

tor


Maintenance

Figure 5–3: Analogue Control Board Block Diagram

M

TILTTORQUERCOIL

PICKOFFCOILS

TILT

TILTMOTOR

Run

Align

TILT TEMPT+ T-

TILT BIAS+V Ref -V Ref

+/-

Hemisphere

+/-

Servo Enable

SCALING&

SHAPING

AMPLIFIER

FILTER&

AMPLIFIER

SCALING

SHAPING&

FILTER& PICKOFF

AZIMUTH

AZIMUTHMOTOR

COILS

M

COMPARATOR

COILTORQUERAZIMUTH

Align

DG

AZIMUTH TEMPT+ T-

AZIMUTH BIAS+V Ref -V Ref

Run

X10

AlignRun

Hemisphere (+/-)Servo Enable

DG

19.2 Khz Ref

Acc/Cosλ

ACCELEROMETER

THERMISTORAMPLIFIER

THERMISTORT+

T-

To Tilt & Azimuthtemperature pots

PRECISIONREFERENCE

Temperature

+V Ref

-V Ref

DIGITAL CONTROL BOARD ANALOGUE CONTROL BOARD GIMBAL ASSEMBLY

Hemisphere

36V26V

0V

R4R1

R2

ReferencePhase26V Synchro36V Resolver

400HzRESOLVERROTOR

STATORRESOLVER

S1

S311.8V Synchro8V Resolver

Heading Outputs

S2

S4

+/-

+/-

400Hz Ref

400Hz Ref

Wheel Boost

2.5V 19.2KhzPickoff Supply

Gyro Spin MotorSupply

MONO -STABLE

10V/18V 480Hz

V.Sin H.Tan λ R

Acc (High Gain)

Acc (Low Gain) τ = 60s

V.Cos HR

Rate of Turn RoT +/- 10V

10V/18V

10V/18V

∅1

2∅

PLD3.6Mhz

+24V

-24V

400Hz

19.2Khz

BANDPASSFILTER

400Hz Ref

400Hz Ref

BANDPASSFILTER

19.2Khz Ref

Sin H

Cos H

8V.Sin H

8V.Cos H

V = speed (knots x 6080 ft/hr)

λ = local latitude (deg) H = gyro heading (deg) τ = time constant Acc = accelerometer signal

Servo Enable

ω Sin λ

AC OK

+/-

+/-Azimuth Pickoff (d.c.)

Tilt Pickoff (d.c.)

REG+

REG-

480Hz ∅ 0

180∅ 480Hz 90∅ 480Hz

270∅ 480Hz

North seaking

Latitude correction

Easterly speed correction

Northerly speed correction

Damping

ω = earth rotation (15°/hr)

R = earth radius (20.9 x 106 ft)

(temp sensor)

(vertical sensor)



Figure 5–4: Digital Control Board/Remote Control Board Block Diagram

AlignRun

Hemisphere (+/-)Servo EnableDG

Acc/Cosλ

Temperature

ANALOGUE

Wheel Boost

V.Sin H.Tan

λ

R

Acc (High Gain)Acc (Low Gain)

V.Cos HR

Rate of Turn

400Hz Ref

Sin HCos H

V = speed (knots x 6080 ft/hr)

λ = local latitude (deg) H = gyro heading (deg) τ = time constant Acc = accelerometer signal

ω Sin λ

AC OK

Azimuth Pickoff (d.c.)Tilt Pickoff (d.c.)

ω = earth rotation (15°/hr)

R = earth radius (20.9 x 106 ft)

ANALOGUEMUX &10 BITADC

Tem

pera

ture

Azi

mut

h P

icko

ff (d

.c.)

Tilt

Pic

koff

(d.c

.)A

cc (L

ow G

ain)

Acc

(Hig

h G

ain)

RX TX

MAX487DRIVERRS422

P4

OPTO-COUPLER

PWMO

P2

P0

uCONTROLLER80C552

X1P4

XTAL

27C512EPROM

ADDR. BUS

DUARTSCN2681

CS

RS232/RS422 I/F

RS422DRIVERS

RS232DRIVERS

ADDR.DECODER CS

RAMHM62256

28C16AEPROM

AC OK

RESOLVERTO DIGITAL

CONVERTER

CS

LS373LATCH

AD7528DAC

CSAcc (Low Gain)

AD7528DAC

Cos H10V Ref

Sin H

AD7528DAC

10V Ref

CS

CS

CS

SCN2681DUART

CONTROL BOARDDISTRIBUTION BOARD

LS373LATCH

CS

SUPERVISORYPSU

MAX8213

DC PSU

System FailSystem Ready

Stepper O/P3 x RS232 IEC 611629 x RS422 IEC 61162RS422 Heading/ROT

GPS SerialNMEA 0183 All Data

Speed Log Serial

Speed Log Pulses

Remote Control

Course Recorder

Spare

DG Mode

RS422 I/FRS232/

CS

DAT

A B

US

DIGITAL CONTROL BOARD

400Hz RefCos H

Sin H

REMOTE CONTROL BOARD

ADDR. BUS

Remote Control

P4

uCONTROLLER

RX

MAX487DRIVERRS422

MAX813LWATCHDOG

80C32X1 XTAL

PWMO

P2

P0

TX

CS

EPROM28C16A

HM62256RAM

ADDR.DECODER

EPROM27C512

DA

TA B

US

WD1 PFO

RESET RESETCS

CS

CS

DISPLAYDRIVER

CS

LATCHLS373

CS

LS373LATCH

DISPLAY

READYSYSTEM

SOUNDERFAIL

KEYBOARD


Maintenance

Table 5–3: Spares list for Meridian Gyrocompass

TSS P/N Description

929033 Gimbal assembly

929066 Control Board Analogue

929083 Control Board Digital

929049 Control Board Remote

929045 Display Board

929074 DC/DC Power Supply

856000 Filter #1 (Schaffner)

929160 Filter #2 (Vicor)

346808 Fuse link 3.15A 250V

929164 Gland Plate assembly

929190 RCU Mounting Kit

930626 Transit case

929220 Test box




Index

AAdjustments

Azimuth bias 5–3Azimuth drift 5–2Test connector 5–3Tilt bias 5–2

Alignment 2–4, 2–13Analogue Rate of Turn

DIP-switch settings 2–12Output connection 2–9Specification 4–2, 4–17

Azimuth bias adjustment 5–3

CCable types 2–4Cautions

All 1–1Handling 2–2Making external connecting 2–5Operating limitations 4–1Power supply 4–1Removing power 2–2Repair and adjustment 5–1See WarningsTilt limits 2–3Ventilation 2–3

Controls 3–2Corrections

See Latitude CorrectionSee Speed Correction

Course recorder output 4–16

DDG Directional Gyro 3–5DIP switches 2–11Dip switches

Analogue rate of turn 2–12Outputs 2–12Vessel dynamics 2–12

EError modes

GPS 3–6Gyro failure 3–7, 3–8Relay output connections 2–9See MaintenanceSpeed log 3–6

GGPS

Baud Rates 4–2Corrections for gyrocompass 1–3, 1–5Data formats 4–4Input socket connections 2–8Loss of GPS 3–6

Gyro failure 3–7Gyrocompass configuration 2–11

HHigh Speed Craft

See Vessel Dynamics

IIEC61162

Data Format 4–5Input data formats 4–6Specification 4–3

InputsConnections 2–8Power connections 2–7Pulsed speed log 4–10Speed log 4–9

InstallationAlignment 2–4, 2–13Choosing a location 2–3DIP switches 2–11Installation Drawings 2–14Suitable cables 2–4Tools 2–4Vessel Dynamics 3–10

LLatitude Correction

Automatic 1–5Enabling 3–4GPS data formats 4–4Manual 3–4RCU display formats 3–2

MMaintenance

Error modes 3–6Operation during lay-up 3–9Test box 5–1Test connector 5–3

DPN 060070 © TSS (International) Ltd Issue 3.11 Index Page 1 of 2


NNMEA

Data Format 4–5Input data formats 4–6Log input data formats 4–9Specification 4–3

NMEA data formats 4–5

OOperation

Continuous operation 3–9During lay-up 3–9Power failure 3–9Power-off 2–2, 3–9Power-on 3–3Vessel Dynamics 3–10

Output formatsAnalogue rate of turn output 4–17Course recorder 4–16Resolver 4–16Serial NMEA / IEC61162 4–5Stepper S-code 4–17Synchro 4–16

OutputsApplication 1–5Connections 2–9Data formats 4–4

PPower

Before switching-on 3–3Supply requirements 4–1Switching off 2–2, 3–9

RRate of Turn

See Analogue Rate of TurnSerial data format 4–12

RCUControls 3–2Description 1–4Dimensions and Weight 4–2Display formats 3–2External connections 2–8, 2–9External location 2–10Installation Drawing 2–16

Resolver output 4–16

SSpeed Correction

Automatic 1–5Enabling 3–5GPS data formats 4–4Input connections 2–8Log Data formats 4–9Pulsed log input 4–10RCU display formats 3–2

Speed LogBaud Rate 4–2Input connections 2–8Loss of speed signal 3–6Serial data formats 4–9

Stepper S-code output 4–17Synchro output 4–16Synchro output connections 2–9

TTest box 5–1Test connector 5–3Tilt bias adjustment 5–2

VVessel Dynamics

Dip switches 2–12Operating considerations 3–10

WWarnings

All 1–1Disposal 4–2Lifting 2–2Safety of personnel 5–1See CautionsSee Error Messages

Index Page 2 of 2 Issue 3.11 © TSS (International) Ltd DPN 060070

Documents

060070 Meridian Gyrocompass