scope:

IEC 61139-2:2022 specifies the extensions to SDCI in IEC 61131-9 for functional safety. This comprises: • a standardized OSSDe interface for redundant switching signals based on IEC 61131-2, • minor modifications/extensions to state machines of SDCI to support the safety operations, • a lean functional safety communication protocol on top of the standard SDCI communication which is a black channel according to IEC 61784-3:2021, • protocol management functions for configuration, parameterization, and commissioning, • IODD extensions for functional safety, • a Device tool interface to support Dedicated Tools according to functional safety standards. This document does not cover: • communication interfaces or systems including multi-point or multi-drop linkages, • communication interfaces or systems including multi-channel or encrypted linkages, • wireless communication interfaces or systems, • integration of SDCI-FS into upper-level systems such as fieldbuses/FSCPs.