Forced Dormant Error Detection - Siemens SINAMICS V90 Operating Instructions Manual

Safety Integrated function
9.4 Safety Integrated basic function
9.4.2

Forced dormant error detection

Forced dormant error detection or test of the switch-off signal paths for Safety Integrated basic
functions
The forced dormant error detection function at the switch-off signal paths is used to detect
software/hardware faults at both monitoring channels in time and is automated by means of
activation/deactivation of the "Safe Torque Off" function.
To fulfill the requirements of ISO 13849-1:2015 regarding timely error detection, the two
switch-off signal paths must be tested at least once within a defined time to ensure that they
are functioning properly. This functionality must be implemented by means of forced dormant
error detection function, triggered either in manual mode or by the automated process.
A timer ensures that forced dormant error detection is carried out as quickly as possible.
8760 hours for the forced dormant error detection.
Once this time has elapsed, an alarm is output and remains present until forced dormant
error detection is carried out.
The timer returns to the set value each time the STO function is deactivated.
When the appropriate safety devices are implemented (e.g. protective doors), it can be
assumed that running machinery will not pose any risk to personnel. For this reason, only an
alarm is output to inform the user that a forced dormant error detection run is due and to
request that this be carried out at the next available opportunity. This alarm does not affect
machine operation.
Examples of when to carry out forced dormant error detection:
● When the drives are at a standstill after the system has been switched on (POWER ON).
● When the protective door is opened.
● At defined intervals.
● In automatic mode (time and event dependent)
Note
The timer will be reset if the associated forced dormant error detection is executed. The
corresponding alarm is not triggered.
The forced dormant error detection procedure of Safety Function (STO) always has to be
executed through the terminals.
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SINAMICS V90, SIMOTICS S-1FL6
Operating Instructions, 04/2020, A5E37208830-008