20. April 2021 22:08 by Christian
in EMC/EMI, EMC TEST PLAN
One common mistake in EMC Test Plans is to associate Pass/Fail criteria with DUT Operating Modes.
For Operating Modes it is critical to define how DUT's:
1) Load Simulator & Support Equipment is configured.
2) Functions are activated.
3) Behavior is monitored.
4) data is collected and reported.
Defining Pass/Fail Criteria for a particular Operating Mode maybe in conflict with requirements listed by automotive OEM EMC spec or standard. The DUT performance and response behavior will always vary depending on the Test Method.
Based on Functional Status Classification the Pass/Fail Criteria must be specified for each Test Method while the DUT is activated in a particular Operating Mode.
For example, ISO 7637-2 Pulse #1 (t2 is 0V for 200 ms). I doubt that an E-Net port won’t miss data packets generating bit errors under such circumstances. Depending on the Test Method and required immunity severity level the EMC spec/standard would allow certain self-recoverable DUT anomalies. Since the EMC Test Plan can override the EMC spec requirement would be a mistake to mention something like "no loss of E-Net data packets" as pass criteria for "DUT Operating Mode #1". This would imply that loosing one packet of data during Pulse #1 the DUT "fails" when in fact the EMC spec would allow it:
"One or more functions of the DUT can go beyond specified tolerance provided that all functions return within normal limits after the exposure is removed (e.g., after UA power is re-applied after the 200 ms defined by t2 as defined in ISO 7637-2). No damage or degradation of memory functions is permitted."