openSAFETY utilizes the Black Channel principle, i.e. it works as an implementation on top of an existing, unaltered SERCOS III solution.
The cross-traffic feature provided by SERCOS III is used by openSAFETY for cyclical safe data exchange. SSDOs are transmitted on the non-real-time (NRT) channel. Ideal docking is ensured for openSAFETY via SERCOS III function profiles (FSP).
The openSAFETY over SERCOS III specification contains a complete description of all mechanisms and functions.