Dependability and safety concepts for EMC

The aim of this article is to build bridges between the fields of Electro-Magnetic Compatibility (EMC) and Dependability. Historically, there has been little communication between these two fields, despite the fact that their goals are technically linked and that they could enrich each other, including methodologically.

This lack of communication has deep historical roots. It is particularly noteworthy that EMC engineers have created their own scale of severity of effects to compensate for the lack of suitable proposals from SoF engineers. In fact, CEM focuses on effects that are highly dependent on the dynamics of the causes, whereas SoF focuses on stationary effects. In addition, SoF is strongly focused on safety aspects, whereas EMC has retained a spectrum of effects ranging from minor disturbance to loss of function. Finally, test-based EMC has retained a margin-of-safety approach, whereas reliability seeks to define probabilities through resistance-stress modeling.

The effects of this lack of communication are numerous. EMC constraints are often left to the designer and not taken into account by the SoF. At the same time, SoTL requirements are poorly understood, poorly taken into account and, ultimately, poorly tested in terms of their EMC aspects. As a result, EMC tests often fail to integrate the full dimension of the system's mission into the parameterization of constraints applied during testing.

Dependability is the activity which guarantees that a product will perform the functions for which it was designed, without unacceptable risks for its operators and the environment.

Considering that SoF has already been extensively covered in other bases of Techniques de l'Ingénieur, this article will not go into detail on the methodological aspects of SoF, even though some of them, such as fault trees, may be of great heuristic interest for EMC. It will therefore concentrate on the link between EMC and SoTL from a less conventional point of view, focusing on the definition and testing of operational safety requirements, and systematically clarifying their significance from an EMC point of view.

After observing the many possible bridges between SoF and EMC along a typical development cycle, the different types of requirements encountered in SoF will be defined and characterized as being useful for EMC. Finally, the means of testing these requirements will be detailed, particularly from an EMC point of view.