Siemens SIMATIC PCS 7 Operating Manual page 111

How to program user acknowledgment via an OS
1. Add the F_QUITES F-block to your safety program. You can access the acknowledgment
signal for evaluation for user acknowledgments at the output OUT of F_QUITES.
2. Interconnect the OUT output of F_QUITES with the ACK_REI input of the F-channel
drivers.
3. Configure a button on your OS for writing the "Acknowledge value" "6"
(first acknowledgment step) and a second button for writing "Acknowledge value" "9"
(second acknowledgment step). Connect the buttons to the IN input of F_QUITES.
4. Optional: On your OS, evaluate the output Q of F_QUITES to show the time window
within which the 2nd. acknowledgment step must be completed (making the second
button visible) or to show that the 1st acknowledgment step has already been completed.
Note
Automatic reintegration using F_QUITES:
The non-safety-related input IN of F_QUITES must not be interconnected with a signal or
described by a signal which generates the above condition (change from 6 to 9 within a
minute) automatically for a fail-safe acknowledgment.
Fail-safe acknowledgment must only be generated by means of a conscious manual entry on
the ES/OS (not automatically in the program).
Example: Implementing F-user acknowledgment in the OS
All "ACK_REQ" channel driver outputs are grouped by means of an OR in the standard user
program and made available to the OS via a DIG_MON block.
Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB
7.7 Passivation and reintegration of input/output channels
Configuring the safety program
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