Step 9: Programming The Feedback Monitoring - Siemens SIMATIC S7 Functional Safety Manual

Getting started
2.3 Programming
2.3.6

Step 9: Programming the feedback monitoring

In this step, you program the feedback circuit monitoring for this example.
The feedback circuit provides protection against restarting normal operations while unsafe
conditions still exist. The system can only be restarted when the emergency stop is
cancelled, the safety door is closed, and the laser scanner detects no one in the protected
area.
Click the "Play" button to start the animation file. Click the other control elements to rewind,
pause, go back, or go forward.
Procedure
1. Insert a new network.
2. Insert the "AND logic operation" instruction from the "Bit logic operations" subfolder of the
"Instructions" task card.
3. Initialize the inputs of the instruction with parameters as described in the table below
4. Insert the "FDBACK" instruction from the "Safety functions" subfolder of the "Instructions"
task card.
5. Click "OK" to confirm the "Call options" dialog.
6. Initialize the inputs and outputs of the instruction with parameters as described in the
table below.
7. Connect the output of the "AND logic operation" instruction to the "ON" input of the
"FDBACK" instruction.
Result
The programming of the feedback monitoring is now complete.
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S7-1200 Functional Safety Manual
Manual, 02/2015, A5E03470344-AA