Siemens SIMATIC ET 200AL, System Manual

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Functions
5.2 Intelligent IO devices (I-devices)
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Function Manual, 05/2021, A5E03444486-AL
5.2.7 Diagnostics and interrupt characteristics
Diagnostics and interrupt characteristics
S7 CPUs have numerous diagnostics and interrupt functions that can, for example, report
errors or failures of lower-level IO systems. These diagnostics messages reduce down times
and simplify localization and elimination of problems.
Diagnostics options in the higher-level IO controller and in the I-device
The following diagnostics functions are available to the higher-level IO controller and the I-
device CPU:
•
OB 83 (pull/plug)
• OB 86 (rack failure)
• OB 122 (I/O access error)
Note
The diagnostics messages of the I/O can be processed in the user program of the I-device
CPU and passed on from there to the higher-level IO controller via transfer areas.
Operating state changes and station failure / station return
In the following table, you can see which consequences an operating state change or the
failure of an IO controller / I-device of the SIMATIC family has on the respective other(s):
Table 5- 1 Operating state changes and station failure / station return
Initial status Event I-device response Higher-level IO controller
I-device CPU is in
RUN, higher-level
IO controller is in
RUN
The I-device CPU
changes to STOP
- During the updating of the process image
with the instructions "UPDAT_PI" and
"UPDAT_PO" an error report is returned at
the parameter RET_VAL.
With direct IO access to all transfer areas to
the I-device: depending on the type of
error handling, e.g., call of OB 122 (IO
access error).
I-device CPU is in
STOP higher-
level IO control-
ler is in RUN
The I-device CPU is
starting up
Call of OB 100 (startup).
Call of OB 83 (pull/plug) for input
transfer areas to the higher-level IO
controller.
Until call of OB 83 in the case of di-
rect access to the input transfer areas
to the higher-level IO controller: de-
pending on the type of error han-
dling, e.g., call of OB 122 (IO access
error).
Call of OB 83 (pull/plug) for all transfer
areas to the I-device.
Until call of OB 83 in the case of direct
access to the transfer areas to the I-device:
depending on the type of error handling,
e.g., call of OB 122 (IO access error).