Siemens SIRIUS 3SK1 Manual page 192

Configuration / operation
10.2 Explanation of the device's functions
When using a 3SK1 safety relay with instantaneous and time-delayed contacts, the two following
safety notes must always be observed:
NOTICE
In the event of external faults such as:
• Cross-circuit fault
• Short circuit to ground
• Current-source short circuit
and to access the configuration mode for copying a delay time after a reset, the following
device behavior must always be taken into account:
The outputs of stop category 0 switch instantaneously, while the outputs of stop category 1
have a time delay.
The sequence cannot be interrupted.
Exception: Switching off the power supply.
NOTICE
Saving the starting command:
1. If the safe state is restored during the time delay, (e.g. the protective door is closed) and
2. If a sensor is actuated at an input expansion within the system configuration, the entire
For additional notes/explanations on this topic, see the following FAQ
(https://support.industry.siemens.com/cs/ww/en/view/103655974)
NOTICE
Observe the following in the case of protective doors with tumblers:
If the voltage Us is disconnected on devices with time-delayed outputs between switching
the instantaneous outputs and the time-delayed outputs, the delay time expires when the
voltage Us is restored, and the time-delayed contacts change their switch positions.
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the START button is actuated, the safety-related outputs switch to the active position
immediately after the delay time has elapsed.
The actuation of the START button is saved.
The OFF-delayed enabling contacts or outputs of the safety relays 3SK112*-*CB4*
(relay and semiconductor outputs) cannot be retriggered. This means that if an OFF
command in the sensor circuit is canceled before the delay time has elapsed, the delay
time still elapses in full length. If a start command has been issued during this time or if
autostart has been set, after this time has elapsed the OFF-delayed enabling contacts
switch off briefly and switch on again immediately with the instantaneous enabling
contacts (start command is saved).
system is disconnected. If the START button on the basic unit is then pressed while the
sensor on the input expansion is actuated (for instance, if the protective door is open),
the command will be saved by the basic unit. This results in an automatic start of the
system once the sensor at the input expansion is reset (for example, a protective door is
closed again). This system response is identical in the system configuration for all 3SK1
basic units.
SIRIUS 3SK1 safety relays
Manual, 06/2018, A5E02526190021A/RS-AD/004