EMC and software issues for safety instrumented systems in the process sector

For safety related equipment, an approach is taken where risks are identified and mitigated. A life cycle is identified and followed. A system based approach is advocated because of the interactive nature of the software and hardware. An analysis of failures indicates that the majority are present at the point of delivery. IEC-61508 is identified as a key document for those dealing with Safety Instrumented Systems. Various methods are suggested to improve the robustness of the system; these are included to mitigate risks, irrespective of where the origin of the risk lies