Evaluating The Sf Led In Case Of Software Errors - Siemens Simatic S7-300 CPU 31xC Series Installation And Operating Instructions Manual

10.6.3

Evaluating the SF LED in case of software errors

Table 10-3
Possible errors
TOD interrupt is enabled and
triggered. However, a matching
block is not loaded.
(Software/configuration error)
Start time of the enabled TOD
interrupt was jumped, e.g. by
advancing the internal clock.
Delay interrupt triggered by
SFC 32. However, a matching
block is not loaded.
(Software/configuration error)
Process interrupt is enabled and
triggered. However, a matching
block is not loaded.
(Software/configuration error)
Status alarm is generated, but
the appropriate OB55 is not
loaded.
Update alarm is generated, but
the appropriate OB 56 is not
loaded.
Vendor-specific alarm is
generated, but the appropriate
OB57 is not loaded.
Access to missing or defective
module upon updating the
process image (software or
hardware error)
The cycle time was exceeded.
Probably too many interrupt
OBs called simultaneously.
Programming error
•
•
•
•
•
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
Evaluation of the SF LED (Software error)
Block not loaded
Wrong block number
Wrong timer/counter number
Read/write access to wrong
area
Etc.
Debugging functions, diagnostics and troubleshooting
10.6 Diagnostics using status and error LEDs
Response of the CPU
Calls OB85. CPU does
not STOP if OB85 is
loaded.
Calls OB80. CPU does
not STOP if OB80 is
loaded.
Calls OB85. CPU does
not STOP if OB85 is
loaded.
Calls OB85. CPU does
not STOP if OB85 is
loaded.
Calls OB85. CPU does
not STOP if OB85 is
loaded.
Calls OB85. CPU does
not STOP if OB85 is
loaded.
Calls OB85. CPU does
not STOP if OB85 is
loaded.
Call OB 85 (depending
on the configuration in
HW Config). CPU goes
into STOP if OB 85 is not
loaded.
Call OB80. CPU
switches to STOP if
OB80 is not loaded. The
CPU switches to STOP
despite loaded OB80 if
the doubled cycle time
was exceeded without
retriggering cycle time
80.
Calls OB121. CPU does
not STOP if OB121 is
loaded.
Remedies
Load OB10 (OB number is apparent
from the diagnostic buffer).
Disable the TOD interrupt before you
set the time-of-day with SFC 29.
Load OB 20 or 21 (CPU 317 only) (the
OB number can be viewed in the
diagnostic buffer).
Load OB40 (OB number is apparent
from the diagnostic buffer).
Load OB55
Load OB56
Load OB57
Load OB85, the start information of the
OB contains the address of the relevant
module. Replace the relevant module
or eliminate the program error.
Extension of the cycle time (STEP 7 –
Hardware configuration), changing the
program structure. Remedy: If
necessary, retrigger cycle time
monitoring by calling SFC 43
Eliminate the programming error. The
STEP 7 testing function helps you to
locate the error.
10-11