IEEE West Michigan EMC Chapter Watson EMC Scanner
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- Slide 1
- IEEE West Michigan EMC Chapter Watson EMC Scanner
- Slide 2
- Introduction Created as a senior project for GVSU sponsored by
sponsored by Gentex and JCI via Jim Teune and Scott Mee Project
team consisted of Xu Li, James Koehler, Schuyler Burson, Troy
Forrest Scanner is available for public use. Talk to Dr. Adamczyk
System can be benchmarked Thanks to Mr. Don Ferris for his generous
help, its impossible to build this scanner without him
- Slide 3
- Near Field Probing Less than 1 , which at 3 GHz is 10cm.
Intensity in the near field decays more rapidly with distance from
the source that in the far field. E field and H field intensity can
be independent and one can be dominant.
- Slide 4
- Near Field Probes H-field E-Field
- Slide 5
- Clock 5 Radiated Emissions
- Slide 6
- Probe Comparison H-Field Probe E-Field Probe Room for
improvement: Design to consider both H and E fields
- Slide 7
- H-Field Orientation Comparison Loop is parallel to current Loop
is perpendicular to current Room for improvement: Design to
consider 2 or more probe orientations (rotate)
- Slide 8
- Correction Factors Application of probe correction
characteristics can be used to maintain a level frequency
response.
- Slide 9
- Use of near field scanning Provides additional understanding of
circumstances. Debugging mysterious noise sources. Its just
cool
- Slide 10
- Example: External Module Radiated emissions failure caused by
external device not product.
- Slide 11
- Example: Component Level 100MHz shows emissions coming from the
display module
- Slide 12
- Example: Gain further understanding of module operation and
failure
- Slide 13
- Example: Characterize software effects
- Slide 14
- Components Main Components: Canon PowerShot SX110 IS Asymtek
xyz-positioner Rohde & Schwarz FSL3 Spectrum Analyzer Probes
(can be different) Computer Others: Pre-Amplifier Fixtures and
Clamps Work Surface
- Slide 15
- Budget Original Budget DescriptionExpected Cost Camera$1000
Capture Card$500 Cables$250 Cart Fixture Supplies$200 NI Vision
DeveloperN/A Asymtek PositionerDonation (Gentex) Pre-amplifierGVSU
Sniffer ProbesGVSU NI LabviewGVSU Spectrum AnalyzerGVSU TOTAL$2000
Final Cost DescriptionExpected Cost Camera$120 + $95 (software)
Capture CardN/A CablesN/A Cart Fixture SuppliesDonation (Gentex) NI
Vision DeveloperGVSU Asymtek PositionerDonation (Gentex) Work
SurfaceDonation (JCI) Pre-amplifierGVSU Sniffer ProbesGVSU NI
LabviewGVSU Spectrum AnalyzerGVSU Other$100 TOTAL$315
- Slide 16
- Communication Between Parts
- Slide 17
- Camera Technical Challenges: o Resolution: 8 inch by 8 inch
image with enough resolution to distinguish individual pins on IC o
Fisheye Effect: Distortion along the edges of the photograph o
Parallax: Displacement or difference in the apparent position of an
object o Communication: Interface with LabVIEW
- Slide 18
- Parallax Low Resolution Fisheye Take 8"x8" image from 10" away
Acceptable resolution for most components
- Slide 19
- Canon PowerShot SX110 IS Remote via PSRemote dll through
Labview 6.0mm - 60.0mm Focal Length 9.0MP $120 used camera $95
Software
- Slide 20
- Image From PowerShot SX110 Note: Fish eye and parallax can also
be reduced by distancing the camera from the DUT however resolution
may be reduced
- Slide 21
- Asymtek xyz-positioner RS232 Connection Interface First In,
First Out buffer containing ASCII coded commands. Minimum Motor
Step Size: 0.001 in. (0.0245 mm)
- Slide 22
- Positioner Communication "Command to send" is an input string
containing the command sent to the positioner through RS232. This
example opens the port, delays 50ms, writes to the port, delays
50ms, reads the bytes from the port, and then closes the port.
- Slide 23
- Definition of position [0,0] Consider center of image as [0,0]
Probe is not concentric with camera. This requires an offset.
Distance from [0,0] and size of selected scan area are in pixels
and must be converted to distance.
- Slide 24
- Pixel-distance calibration and need for height from work
surface
- Slide 25
- Room for improvement: Automated Vertical Distance
Detection
- Slide 26
- Rhode & Schwarz FSL3 9kHz-3MHz Ethernet communication
300Hz-10MHz resolution bandwidth 1Hz-10MHz Video bandwidth
Suggested 30dB pre-amplifier Room for improvement: Included
communication drivers for multiple Spectrum Analyzers
- Slide 27
- Any* Near Field Probe can be Used Designed to accommodate
Langer probe sets & VanDoren probe sets. Universal probe mount
allows for alternate fixtures. Probe correction factors can be used
if provided in proper format. Room for improvement: Design to
ensure consistent vertical position of probe relative to mount
- Slide 28
- Main Software - LabVIEW and Add-ons o LabVIEW 2012: GUI,
Control and Data Acquisition of SA, Control of Positioner o VDM:
Image Processing such as Density Color Overlay o Microsoft Office
Report Generation Kits o PSRemote: Third party software for
remotely controlling camera
- Slide 29
- PSRemote 1. Dynamic-link library (.dll) files were converted to
LabVIEW sub-VIs. 2. Communication was approved. 3. Executable file
(.exe) file must be running to provide the functionality of
connecting to the camera
- Slide 30
- How Scanner Works Complete System Flowchart Subprocesses
explained in detail in following sections.
- Slide 31
- How Calibration Works Calibrates motor step sizes and
pixel/physical area ratio Compares hard-coded pixel sizes and
locations with physical shaded grid section.
- Slide 32
- How Scanning Works Positioner moves in snake-like pattern over
selected area. The maximum value in each reading of the spectrum
analyzer is placed into an array. "Home" is the corner of the
overall work area, not the user selectable area.
- Slide 33
- How Image Overlay Works 1. Obtain Scan Area Image 2. Treat Data
from SA 3. Overlay Data on Image 4. Save Final Image
- Slide 34
- References Langer-emv.com Dong, X., Deng, S., & Beetner, D.
(n.d.). Analysis of Chip-level EMI using Near-Field Magnetic
Scanning. Retrieved June 25, 2014
- Slide 35
- Q&A