Forced Checking Procedure (Test Stop); Forced Checking Procedure Or Test Of The Switch-Off Signal Paths (Test Stop) For Safety Integrated Basic - Siemens SINAMICS S120 Function Manual

Safety Integrated Basic Functions
11.2 General information
11.2.6

Forced checking procedure (test stop)

11.2.6.1 Forced checking procedure or test of the switch-off signal paths (test stop) for Safety
Integrated Basic
The forced checking procedure (test stop) 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" (STO) or "Safe Stop 1" (SS1) function.
To fulfill the requirements of ISO 13849-1 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 using the forced checking
procedure (test stop), triggered either in the manual mode or by the automated process.
A timer ensures that forced checking procedure (test stop) is carried out in a timely fashion.
● p9659 SI forced checking procedure, timer.
A forced checking procedure (test stop) must be performed on the switch-off signal paths at
least once during the time set in this parameter.
Once this time has elapsed, an alarm is output and remains active until forced checking
procedure (test stop) is carried out.
The timer returns to the set value each time the STO/SS1 function is deactivated.
Note
Resetting the timer of the Basic Functions
When simultaneously using the Extended Functions, if the forced checking procedure (test
stop) is performed, then the timer of the Basic Functions is also reset.
While STO is selected by the Extended Functions, the terminals for the selection of the Basic
Functions are not checked for discrepancy. This means that the forced checking procedure
(test stop) of the Basic Functions must always be performed without the selection of STO or
SS1 by the Extended Functions. It is otherwise not possible to verify the correct control by the
terminals.
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. The user is therefore only
informed that the forced checking procedure (test stop) is due in the form of an alarm, which
requests the user to perform forced checking procedure (test stop) at the next possible
opportunity. This alarm does not affect machine operation.
The user must set the time interval for carrying out forced checking procedure (test stop) to
between 0.00 and 9000.00 hours depending on the application (factory setting: 8.00 hours).
Examples of when the forced checking procedure (test stop) must be performed:
● 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).
● The maximum time interval is one year (8760 hours).
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Function Manual, 06/2019, 6SL3097-5AB00-0BP2
Drive functions