Defective State - Siemens CPU 410-5H Process Automation System Manual

Operator controls and operating modes of the CPU 410-5H
7.1 Operating modes of the CPU 410-5H
The purpose of ERROR-SEARCH operating state is to find a faulty CPU. The standby CPU
runs the full self-test, while the master CPU remains in RUN. If a hardware fault is detected,
the CPU changes to DEFECTIVE state. If no fault is detected the CPU is linked up again.
The fault-tolerant system resumes the redundant system state. An automatic master-standby
changeover then takes place. This ensures that when the next error is detected in error-
search mode, the hardware of the previous master CPU is tested.
No communication is possible, e.g., by means of access from a programming device, while
the CPU is in ERROR-SEARCH operating state. The ERROR-SEARCH operating state is
indicated by the RUN and STOP LEDs, see Chapter Status and error displays (Page 37).
For additional information on the self-test, refer to Chapter Self-test (Page 104)
7.1.7

DEFECTIVE state

The CPU enters the DEFECTIVE state when an error occurred that cannot be automatically
eliminated by the operating system.
Reaction of the CPU
The reaction of the CPU in the DEFECTIVE state is intended to leave this state, if possible,
and to restart.
The CPU reacts as follows in DEFECTIVE state:
1. The CPU writes the cause of the defect into the diagnostic buffer.
2. The CPU performs a memory dump.
3. The CPU backs up the extended diagnostic data.
4. The CPU checks the consistency of the user data.
The CPU cannot leave the DEFECTIVE state independently if the user data show
inconsistencies.
5. The CPU checks the time stamp of the last automatic reboot.
If an entire day has not passed since the last automatic reboot, the CPU cannot leave the
DEFECTIVE state independently any longer.
6. The CPU checks the event that has caused the transition to the DEFECTIVE state.
The CPU cannot leave the DEFECTIVE state independently if the event prevents an
automatic reboot.
7. The CPU saves the current user data retentively.
8. The CPU saves the time stamp of the current reboot retentively.
9. The CPU writes an event 0x4x09 ("Memory reset started automatically") to the diagnostic
buffer.
10.The CPU performs an automatic reboot.
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CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 10/2013, A5E32631667-AA