prEN IEC 61139-2:2021

This part 2 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.