worst-case elapsed time of a safety function, following an actuation of a safety sensor connected to a fieldbus, until the corresponding safe state of the safety function’s actuator(s) is achieved, in the presence of errors or failures.

NOTE 1 to entry: This concept is introduced in IEC 617843:—, 5.2.4 and is addressed by the functional safety communication profiles defined in that specification.

[SOURCE: IEC 61784-3:2017, 3.1 modified]