emc testing lab

One of the questions we get asked often is about order of EMI/EMC testing.  Neither MIL-STD-461 nor RTCA/DO-160 specify the order of test performance.  Leaving aside the issue of Safety of Flight tests for aircraft (which typically must be performed prior to any other testing), there are a few different approaches to take in this regard.

The first approach is to begin with the most benign tests, usually the emissions.  These tests have virtually no chance of harming the equipment under test (EUT), while conversely they sometimes prove to be the most problematic.  Emissions problems can be notoriously difficult to track down and eliminate, and sometimes solutions to bring them within specification requirements involve redesigns that can have potential effects to other tests.  If the other tests have been performed prior to the emissions testing, then any changes made to bring the emissions into spec would need to be evaluated to determine if the other tests need to be repeated.

The second approach is to begin with the most potentially damaging tests first.  The philosophy here is that all is well and good if the EUT endures those tests with no issues.  However, if there are susceptibilities that require repair/redesign, those problems can be resolved before continuing with the other tests.

The third (and in my opinion best) approach is to perform an analysis of the EUT before going to the lab, to determine what tests are most likely to cause problems, and to start with them.  Similar to the other two approaches, the idea is that any problems resulting from these tests can be identified and fixed before moving on to other testing.  The main difference between this approach and the other two approaches is that because of the analysis performed beforehand, there is some degree of confidence that the subsequent tests will be successful. See more...!