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.