Siemens SIRIUS 3RK3 - Safety Systems - General Information; Safety Function

3.7 Safety systems - General information
3.7.1 Safety function
A safety function describes the reaction of a machine/plant when a speci󹪝c event occurs (e.g.
opening of a protective door). Execution of the safety function(s) is carried out by a safety-
related control system. This usually comprises three subsystems, detecting, evaluating
and and reacting.
Detecting (sensors):
• Detection of a safety requirement
e.g. EMERGENCY STOP or a sensor for monitoring a hazardous area (light array, laser scanner,
etc.) is operated.
Evaluating (safety relay):
• Detection of a safety requirement and the safe initiation of the reaction, e.g. switching o󹪜 the
enabling circuits
• Monitoring the correct operation of sensors and actuators
• Initiating a reaction upon detection of faults
The safety relays described in this manual are evaluation units for safety functions.
Reacting (actuators):
• Switching o󹪜 the hazard by means of downstream actuators
Detecting
(sensors)
Evaluating
(safety relay)
Reacting
(actuators)
Overview
3.7 Safety systems - General information
SIRIUS 3RK3 Modular Safety System
50 Equipment Manual, 07/2020, NEB926253002000/RS-AC/006