IEC 61139-2:2022

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.