SAE J551-1:2020 pdf free

SAE J551-1:2020 pdf free.Vehicle Electromagnetic Immunity – Power Line Magnetic Fields
Setting the immunity test frequencies using a logarithmic relationship is a technique that produces equally spaced frequency steps on a logarithmic scale. The number of steps per octave or decade are based on the expected Q of the DUT. The values agreed upon by the users of this standard shall be documented in the test report. The method of generating this frequency list is developed in Appendix C. Sample frequency lists are included. Figures C1 and C2 in Appendix C ilustrates typical values of Q in each frequency segment.
Immunity testing is commonly done using either one of two different techniques, (a) substitution and (b) closed loop leveling. This paragraph explains the control parameters of each.
a The Substitution Method – The substitution method uses FORWARD POWER as the reference parameter that sets the test level during characterization and the immunity test. The specific test level (E-field, current, voltage or power) is characterized at each frequency per 6.1 .4, by adjusting the forward power to produce the desired test level. This number is recorded and used as the reference parameter for the immunity test. This is done in an empty chamber (absorber lined shielded enclosure, T EM cell, tri-plate etc.) for immunity testing or with a characterization test fixture for bulk current injection. The vehicle test is conducted by subjecting the vehicle to the test levels at each frequency as determined in terms of forward power in the characterization phase.
b. The Closed-loop Leveling Method – This method does not require a characterization prior to the test, however, a pre-characterized sensor must be used to monitor the control parameter throughout the duration of the test .The signal generator level is adjusted based upon input from the control parameter until the desired test level is obtained.
Verification of test item parameters shall be performed in accordance with individual test method’s requirements. The test level versus frequency data shall be established using a CW signal. The method and results for each characterization point shall also be documented.SAE J551-1 pdf free download.