Formalised Implementation of Safety Related HW/SW Architectures in Compliance with Functional Safety Requirements

This paper describes a methodology supporting a component based approach to the design and realisation of architectures for safety related systems. The architecture is modelled using an extended taxonomy which is based on the taxonomy used in IEC 61508-6; the extended taxonomy represents architectural elements in terms of their functional relation such as safety, diagnostic or non-safety-related as well as their implementation in either hardware or software. This makes it possible to model the relation between elements that implement e.g. the safety function and the required diagnostics techniques. The modelled architecture is used to identify and design software components encapsulating one or more of the diagnostic techniques recommended by IEC 61508-2. The modelled architecture and the software components are then mapped onto the operational environment. The methodology has been applied in a case study where a safety related module is developed for a frequency converter.