1 Scope
This part of IEC 61139 specifies the extensions to SDCI in IEC 61131‑9 for functional safety. This comprises:
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• a standardized OSSDe interface for redundant switching signals based on IEC 61131‑2,
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• minor modifications/extensions to state machines of SDCI to support the safety operations,
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• a lean functional safety communication protocol on top of the standard SDCI communication which is a black channel according to IEC 61784‑3:2021,
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• protocol management functions for configuration, parameterization, and commissioning,
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• IODD extensions for functional safety,
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• a Device tool interface to support Dedicated Tools according to functional safety standards.
This document does not cover:
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• communication interfaces or systems including multi-point or multi-drop linkages,
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• communication interfaces or systems including multi-channel or encrypted linkages,
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• wireless communication interfaces or systems,
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• integration of SDCI-FS into upper-level systems such as fieldbuses/FSCPs.