scope:

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.