Debugging functions, diagnostics and troubleshooting
10.6 Diagnostics using status and error LEDs
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
10-15
Table 10-7 BUSF LED flashes
Possible errors CPU reaction To correct or avoid error
The CPU is DP master:
• Failure of a connected station
• At least one of the configured
slaves cannot be accessed.
• Faulty configuration
Call of OB 86 (when CPU is in RUN
mode). CPU switches to STOP if OB
86 is not loaded.
Verify that the bus cable is connected
to the CPU, or that the bus is not
interrupted.
Wait until the CPU has completed its
startup. If the LED does not stop
flashing, check the DP slaves or
evaluate the diagnostic data for the DP
slaves.
The CPU is active DP slave
Possible causes:
• The response monitoring time has
expired.
• PROFIBUS DP communication is
down.
• Wrong PROFIBUS address.
• Faulty configuration
Call of OB 86 (when CPU is in RUN
mode).
CPU switches to STOP if OB 86 is not
loaded.
• Check the CPU.
• Verify that the bus connector is
properly seated.
• Check for breaks in the bus cable to
the DP master.
• Check the configuration data and
parameters.
Reference
Details on the OBs and on SFCs required for their evaluation can be found in the
STEP 7
Online Help
and in the Manual
System Software for S7-300/400 - System and Standard
Functions
.
To Next Page
Loading...
Need help?
General
