Note: Enabling current paths can also be used for signaling purposes.
3.7.3.4 Solid-state signaling output
A signaling output provides a safety-related output signal. This can be used to signal system
states, for example. Signaling outputs must not be used in safety functions.
3.7.3.5 Feedback circuit
A feedback circuit serves to monitor controlled actuators. Only the actuators' positively driven
NC contacts or mirror contacts may be used to read back the switch positions of coupling
contacts or load contactors. The fail-safe outputs can only be activated if the feedback circuit is
closed. One input of the safety relay is needed to read in the feedback circuit. Logical evaluation
of the feedback circuit is implemented in the Safety ES software with the "F output" and "F output
delayed" output functions.
3.7.3.6 Stop categories
Stop category 0
Non-controlled shutdown by immediately switching o the power to the machine's drive
elements.
Stop category 1
Controlled stopping where the energy feed is interrupted with a time delay, or is only interrupted
once standstill has been reached.
Note
Time-delayed shutdown of enabling circuits in accordance with stop category 1 is not ensured
under all operating states.
In the case of some internal device faults, and when disconnecting the supply voltage, these
enabling circuits are switched o instantaneously. This must be considered during the risk
analysis and when designing the system.
3.7.3.7 Start function and types
Start functions
After triggering of a safety function and recovery of the enabled state (e.g. protective door has
been opened and is closed again), it is necessary for the user to reset the safety-related control
system by means of a further manual action. This reset is generally performed by operating a
button.
Overview
3.7 Safety systems - General information
SIRIUS 3RK3 Modular Safety System
Equipment Manual, 07/2020, NEB926253002000/RS-AC/006 53
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