Self-Test; Table 8-3 Reaction To Errors During The Self-Test - Siemens SIMATIC S7-400H System Manual

8.5

Self-test

Processing the self-test
The CPU executes the complete self-test program after POWER ON without backup, such
as POWER ON after initial insertion of the CPU or POWER ON with no backup battery, and
in the TROUBLESHOOTING state. The self-test takes about 10 minutes.
When the CPU of a fault-tolerant system request a memory reset and is then shut down with
backup power, it performs a self-test irrespective of the backup function. The CPU requests
a memory reset when you remove the memory card, for example.
In RUN the operating system splits the self-test routine into several small program sections,
so-called 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. The default time of 90 minutes
can be modified in the configuration.
Reaction to errors during the self-test
If the self-test returns an error, the following happens:
Table 8-3
Error class
Hardware fault without one-sided call
of OB 121
Hardware fault with one-sided call of
OB 121
RAM/PIO comparison error
Checksum errors
Multiple-bit errors
Hardware fault with one-sided call of OB 121
If a hardware fault occurs with a one-sided OB 121 call for the first time since the previous
POWER ON without backup, the faulty CPU enters the TROUBLESHOOTING state.
The fault-tolerant system switches to single mode. The cause of the error is written to the
diagnostics buffer.
S7-400H
System Manual, 09/2007, A5E00267695-03
Reaction to errors during the self-test
System and operating states of the S7-400H
System reaction
The faulty CPU enters the 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 enters the
TROUBLESHOOTING state. The fault-tolerant system
switches to single mode (see below).
The cause of the error is written to the diagnostics buffer.
The CPU enters the configured system or operating state
(see below).
The reaction depends on the error situation (see below).
The faulty CPU enters the TROUBLESHOOTING state.
8.5 Self-test
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