Towards Functional Safety in Dynamic Distributed Systems

Abstract

Functional safety (FS) is a well-established concept to avoid technical systems to cause harm during operation. Since FS is based on information exchange, the communication infrastructure plays a vital role to enable FS. Black channel or grey channel approaches are the basis for achieving effective and efficient FS schemes. While simple safety functions (SFs) can be implemented using point-to-point (P2P) transmission protocols, they are usually not suitable to provide FS in dynamic distributed systems (DDSs). This paper discusses time-sensitive networking (TSN) as an important approach for providing FS in wireless TSN (W-TSN) and evaluates the achievable safety integrity levels (SILs) for applications based on PROFISafe running over W-TSN. A discussion on initial ideas for providing FS in DDSs reveals that FS concepts have to be designed and optimized jointly with communication protocols beyond P2P transmission to improve the resulting efficiency required for applying the concepts in industrial processes.