Siemens SIMATIC PCS 7 CPU 410-5H

Operator controls and operating modes of the CPU 410-5H
7.3 Self-test
CPU 410-5H Process Automation
System Manual, 09/2014, A5E31622160-AB
117
RAM/PIQ comparison error
If the self-test returns a RAM/PIQ comparison error, the fault-tolerant system exits the
redundant operating state and the standby CPU switches to ERROR-SEARCH operating
state (in default configuration). The cause of the error is written to the diagnostics buffer.
The response to a recurring RAM/PIQ comparison error depends on whether the error
occurs in the subsequent self-test cycle after troubleshooting or not until later.
Table 7- 4 Response to a recurring comparison error
Comparison error recurs ...
Reaction
in the first self-test cycle after troubleshooting The fault-tolerant system switches to single
mode.
The reserve CPU enters ERROR-SEARCH mode
and then remains in STOP.
after two or more self-test cycles after trouble-
shooting
The fault-tolerant system switches to single
mode.
Standby CPU switches to ERROR-SEARCH.
Checksum errors
When a checksum error occurs for the first time since the last POWER ON without battery
backup, the system reacts as follows:
Table 7- 5 Reaction to checksum errors
Time of detection
System response
During the startup test after
POWER ON
The faulty CPU switches to DEFECTIVE state.
The fault-tolerant system remains in single mode.
In the cyclic self-test
(STOP or solo operation)
The error is corrected. The CPU remains in STOP operating state or
in solo operation.
In the cyclic self-test
(redundant system state)
The error is corrected. The faulty CPU switches to ERROR-SEARCH
operating state.
The fault-tolerant system switches to single mode.
In the
ERROR-SEARCH operating
state
The faulty CPU switches to DEFECTIVE state.
The cause of the error is written to the diagnostics buffer.
In an F-system, the F-program is informed that the self-test has detected an error the first
time a checksum error occurs in STOP or in solo operation.