Self-Test; Table 7- 3 Response To Errors During The Self-Test - Siemens SIMATIC PCS 7 System Manual

Operator controls and operating modes of the CPU 410-5H

7.3 Self-test

7.3 Self-test
Processing the self-test
The CPU executes the complete self-test program after an unbuffered POWER ON, e.g.,
POWER ON after initial insertion of the CPU or POWER ON without backup battery, and in
the ERROR-SEARCH operating state.
The self-test takes about 15 minutes.
When the CPU of a fault-tolerant system requests a memory reset and then undergoes a
OFF/ON cycle with battery backup, it performs a self-test in spite of the battery backup.
In RUN the operating system splits the self-test routine into several small program sections
("test slices") which are processed in multiple successive cycles. The cyclic self-test is
organized to perform a single, complete pass in a certain time. This time interval is at least
90 minutes and can be extended by the configuration to reduce the impact of the self-test on
the runtime of the user program. However, it also extends the time interval in which a
possible error is detected.
Response to errors during the self-test
If the self-test returns an error, the following happens:
Table 7- 3
Type of error
Hardware fault
Hardware fault that is signaled by a
one-sided OB 121 call
RAM/PIQ comparison error
Checksum errors
Multiple-bit errors
Hardware fault with one-sided call of OB 121
If a hardware fault occurs which causes a one-sided OB 121 call and if this fault occurs for
the first time since the previous POWER ON without backup, the faulty CPU enters ERROR-
SEARCH mode. The fault-tolerant system switches to single mode. The cause of the error is
written to the diagnostics buffer.
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Response to errors during the self-test
System response
The faulty CPU switches to DEFECTIVE state. The fault-
tolerant system switches to single mode.
The cause of the error is written to the diagnostics buffer.
The CPU with the one-sided OB 121 switches to ERROR-
SEARCH. The fault-tolerant system switches to solo opera-
tion (see below).
The cause of the error is written to the diagnostics buffer.
The CPU switches to the configured system or operating
state (see below).
The response depends on the error situation (see below).
The faulty CPU switches to ERROR-SEARCH operating
state.
CPU 410-5H Process Automation/CPU 410 SMART
System Manual, 09/2014, A5E32631667-AB