Siemens SIMATIC S7 F, Manual

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Getting Started
Fail-Safe Systems
A5E00085588-03
2-17
2.3.5 Fault-Tolerant S7 FH System, Monitoring Errors
Interruption in the PROFIBUS Connection
1. Remove the PROFIBUS cable from CPU0. The BUS2F LED flashes and the
REDF LED lights up on CPU0.
The second IM 153-2 is now active, and the first one indicates a bus fault.
2. Read out the diagnostic buffer of CPU0. Although there is a loss of redundancy
on the DP slave, your I/O system still continues to operate without error.
3. Now insert the PROFIBUS cable into CPU0 again. All the error LEDs go out
again. However, the second IM 153-2 remains active.
Wire Break on the SM 326F DO10xDC24V/2A with User Acknowledgment
1. Break the connection to your actuator or load resistor, for example on channel
0.
2. Apply voltage to channel 0 of the input module (e.g. from the terminal Vs). Your
output should be set now, but if the output module reports a fault, the SF LED
comes on and the channel LED is off.
3. Display the diagnostic buffer of the CPU and of the output module by means of
Diagnose Hardware: A wire break on channel 0 is reported.
4. Go to the "F blocks" CFC chart, and switch to test mode. The QBAD output of
the F_CH_DO F channel driver blocks are set: The entire module has a fault.
5. Eliminate the wire break.
6. As soon as the output ACK_REQ=1 is set, reintegrate the output module via
F_QUITES (as described for the F-system): The error I/Os no longer report an
error and the SF LED of the module goes out.