Why EMC testing is inadequate for functional safety-and what should be done instead

Abstract

Electronic devices are increasingly used in safety-related and safety-critical applications. But all electronic devices are susceptible to electromagnetic interference (EMI), making their electromagnetic compatibility (EMC) with their environments over their lifecycle a safety issue. So one of the challenges of dealing with these new technologies and more complex systems must be to ensure that EMI cannot cause excessive safety risks. But the EMC Directive and its standards do not cover safety issues, and the EMC or safety standards presently used for safety compliance in the following areas 1) vehicles (rail, road, air, sea or space) 2) transport systems (rail, road, air, sea or space) 3) industrial control and automation 4) robotics 5) nuclear industry 6) defence 7) medicine and healthcare. Either do not address 'EMC for functional safety' issues at all, or else do not employ modern best practices. This paper describes the above situation, and then describes why relying solely on EMC testing cannot demonstrate a sufficient degree of functional safety over a lifecycle. The remainder of this paper then describes EMC design techniques; design verification and quality control suitable for controlling the functional safety risks that could be caused by EMI.