Forced Dormant Error Detection - Siemens SINAMICS S120 Function Manual

Safety Integrated Basic Functions

4.5 Forced dormant error detection

4.5 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 (2006) 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.
● p9659 SI timer for the forced dormant error detection.
Forced dormant error detection must be carried out at least once during the time set in this
parameter.
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.
The user must set the time interval for carrying out forced dormant error detection to
between 0.00 and 9000.00 hours depending on the application (factory setting: 8.00 hours).
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 (e.g. every 8 hours).
● In automatic mode (time and event dependent).
NOTICE
The timer of the Basic Functions will be reset if the associated forced dormant error
detection is executed and the Extended Functions are used simultaneously.
The corresponding alarm of the Basic Functions is not triggered.
Discrepancy is not checked at the terminals used to select the Basic Functions as long as
STO is set by the Extended Functions. That is, the forced dormant error detection
procedure of the Basic Functions always has to be executed without simultaneous selection
of STO or SS1 by the Extended Functions. It is otherwise not possible to verify the correct
control through the terminals.
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Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
Safety Integrated