ČSN EN IEC 61139-2

This part of IEC 61139 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.