Evaluation Of The Sf Led (Hardware Error) - Siemens SIMATIC S7-300 Hardware And Installation Manual

Testing functions, Diagnostics and Fault Elimination
Table 10-4
Possible Errors
A module was removed or
inserted during operation.
A diagnostic-capable module
reports a diagnostic
interrupt.
Attempt to access a missing
or faulty module. Loose
connector (Software or
hardware error).
Faulty Memory Card.
Tip: You can use SFC 39 to disable all interrupts and asynchronous error events.
Tip on OB 32 and OB 35: You can set the times in watchdog OB 32 and OB 35,
starting from 1 ms.
Note
The shorter the selected watchdog interrupt period, the more likely is it that
watchdog interrupt errors will occur. You must take into account the operating
system times of the CPU in question, the user program runtime as well as cycle
time extension, for example, by active PG functions.
Cross-reference
Details on the OBs and on SFCs required for their evaluation is found in the
STEP 7 Online Help and in the Manual System Software for S7-300/400 - System
and Standard Functions.
10-10

Evaluation of the SF LED (Hardware error)

Reaction of the CPU
CPU goes into STOP
OB 82 call. CPU goes
into STOP if OB 82 is
not loaded.86
Call of OB 85, if
access was attempted
during update of the
process image (here,
the OB85 call must be
enabled accordingly in
the parameters). Call
of OB122 with direct
I/O access. CPU goes
into STOP if the OB is
not loaded.
The CPU goes into
STOP mode and
requests memory
reset.
S7-300 Programmable Controller Hardware and Installation
Remedies
Screw-tighten the modules and
restart the CPU.
Reaction to the diagnostic event,
depending on the module's
configuration.
Generate OB 85, the start
information of the OB contains the
address of the respective module.
Replace the respective module,
tighten the plug or eliminate the
program error.
Replace the Memory Card, reset
CPU memory, transfer the program
again and set the CPU to RUN
mode.
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