The importance of failure-criteria definition in immunity testing

In the course of performing compliance tests against EMC standards, experience has shown that the most contentious and problematic tests are those that measure immunity. Standards, most notably the EN61000-4 series in the European Union, go to great lengths to define the procedures, structures and protocols of these tests. However, the definition of failure criteria is left to the discretion of the manufacturer. In an increasingly complex technology, a common understanding of what is and is not an acceptable response to an electromagnetic stimulus is becoming more difficult to reach. This paper proposes a test-planning procedure that has proven effective when used in a commercial-product context.