Specifications

EMC-CS-2009.1
© Copyright Ford Motor Company – All Rights Reserved Page 48 of 121
February 11, 2010
Figure 12-2: RI 140 Magnetic Immunity Test Setup: Radiating Loop
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Configuration for Testing DUT only
Configuration for Testing DUT
with attached Magnetic Sensors
Key:
1. Radiating Loop
2. Signal Source
3. Current Probe
4. Measurement Receiver
5. DUT
6. Load Simulator
7. Artificial Network
8. Ground Plane
9. Magnetic Sensor
12.3.2 Helmholtz Coil Method
a) Prior to performing testing of the DUT, characterize the Helmholtz Coil using procedures delineated in MIL-STD-
461E, RS101.
Select coil spacing based on the physical dimensions of the DUT.
• For a DUT with dimensions less than one coil radius, the coils shall be separated by one coil radius. Separation
between each surface of the DUT and either coil shall be at least 50 mm.
• For a DUT with dimensions greater than one coil radius, the coils shall be separated such that the plane of the DUT
face is at least 50 mm from the plane of either coil and the separation between the two coils does not exceed 1.5
radii.
b)
Supply the Helmholtz Coil with sufficient current to produce the corresponding magnetic field levels delineated in
Figure 12-1 at each test frequency listed in Table 12-1.
c)
Dwell time shall be at least 2 seconds. A longer dwell time may be necessary if DUT function response times are
expected to be longer. This information shall be documented in the EMC test plan.
d)
Reposition the DUT or Helmholtz coils successively such that the two coils are parallel to each face of the DUT and
parallel to the axis of any connector.
e)
If deviations are observed, the field shall be reduced until the DUT functions normally. Then the field shall be
increased until the deviation occurs. This level shall be reported as deviation threshold.
f)
If the DUT has magnetic sensors attached to it, separate tests shall be performed exposing only the sensor while
verifying correct operation of the DUT (see Figure 12-3).