Adapting Cpu Parameters (Fault-Tolerant F System); Reaction To Ram/Piq Comparison Error - Siemens SIMATIC PCS 7 Operating Manual

Configuring S7F/FH hardware

6.2 Adapting CPU parameters (fault-tolerant F system)

6.2 Adapting CPU parameters (fault-tolerant F system)
All settings made in the single F-system must also be made in the fault-tolerant F-system.
Note
Parameters in blue can be changed during operation on an H system.
The following settings must also be made when using redundant CPUs:
● Reaction to RAM/PIQ comparison error
● Cyclic interrupt OB with special handling
● Monitoring times
6.2.1

Reaction to RAM/PIQ comparison error

Troubleshooting
TROUBLESHOOTING mode is set by default in response to a comparison error (default
response). The purpose of troubleshooting is to locate a faulty CPU.
Select how the H system should react to an error generated during the comparison of the
RAM areas and the process images of the outputs:
● Troubleshooting:
TROUBLESHOOTING mode can only be reached from the "Redundant" system state.
If an error occurs in redundant mode and depending on the error, one of the CPUs goes
into TROUBLESHOOTING mode and performs a full self-test. The other CPU becomes
the master. If a hardware error is detected, the CPU goes to DEFECTIVE mode. If no
error is detected, the CPU is coupled again. The H system goes back into the
"Redundant" system state. This is followed by an automatic master-standby switchover.
This ensures that when the next error is detected in troubleshooting mode, the hardware
of the previous master CPU is tested.
Note
To find out which events trigger the TROUBLESHOOTING operating state, please refer
to the "SIMATIC S7-400H Fault-tolerant Systems"
(https://support.industry.siemens.com/cs/ww/en/view/82478488) manual.
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Compendium Part B - Process Safety (V8.2)
Operating Manual, 07/2016, A5E35031794-AB