Siemens S7-300 - The BUSF LED Lights up

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S7-300 Automation System, Hardware and Installation: CPU 312IFM - 318-2 DP
A5E00203919-01
11-11
Table 11-6 The BUSF LED lights up.
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• Bus fault (hardware fault).
• DP interface error.
• Different transmission rates in
multiple DP master mode.
• Bus short-circuit has
occurred.
Calls OB86 (when CPU is in RUN
mode). CPU switches to STOP if
OB 86 is not loaded.
• Check the bus cable for short
or interruption.
• Evaluate the diagnostic data.
Reconfigure, or correct the
configuration.
Table 11-7 The BUSF LED flashes
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CPU is the DP master
• Failure of a connected station
• At least one of the configured
slaves cannot be accessed.
• Incorrect configuration
Calls OB86 (when CPU is in RUN
mode). CPU switches to STOP if
OB 86 is not loaded.
Ensure that the bus cable is
connected to the CPU and that
the bus is not interrupted.
Wait until the CPU has started. If
the LED does not stop flashing,
check the DP slaves or evaluate
the diagnostic data for the DP
slaves.
The CPU is the DP slave
CPU 31x was programmed
incorrectly. Possible causes:
• The response monitoring time
has expired.
• PROFIBUS DP
communication is interrupted.
• Wrong PROFIBUS address.
• Incorrect configuration
Calls OB 86 (when CPU is in
RUN mode).
CPU switches to STOP if OB 86
is not loaded.
• Check the CPU.
• Check to make sure that the
bus connector is properly
inserted.
• Check for interruptions in the
bus cable to the DP master.
• Check configuration data and
the parameters.