Commissioning
8.6 Commissioning PROFINET IO
S7-300, CPU 31xC and CPU 31x: Installation
Operating Instructions, Edition 08/2004, A5E00105492-05
8-39
CPU startup for operation as IO controller
In its startup sequence, and based on the preset configuration, the CPU verifies the actual
configuration
•
of the local I/O,
•
of the distributed I/O on the PROFIBUS DP system, and
•
the PROFINET IO system.
The startup of the CPU is determined by the corresponding configuration in the "Startup" tab:
Table 8-12 CPU startup for operation as IO controller
Preset ≠ Actual configuration
Preset = Actual
configuration
Startup permitted when Preset
configuration = Actual configuration
Startup not permitted when Preset
configuration = Actual configuration
CPU goes into RUN.
CPU goes into RUN. After POWER
ON, and after the parameter
monitoring time has expired, the
CPU goes into RUN.
The flashing BUSF LED indicates
that at least one IO device can not
be addressed. In this case, verify
that all IO devices are switched on
and correspond with the set
configuration. For further
information, read the diagnostics
buffer in STEP 7.
CPU startup fails
Detecting interruptions in the data transfer to the IO device
The table below shows how the CPU 31x-2 PN/DP detects interruptions of the data transfer:
Table 8-13 Event detection by the CPU 31x-2 PN/DP operating as IO controller
What happens in the IO controller?
Event
CPU in RUN
CPU in STOP
Bus interrupt (short-circuit,
connector removed)
•
Call of OB86 with the
message Station failure
(coming event; diagnostics
address of the IO device)
•
With I/O access: call of
OB 122
(I/O access error)
•
The event is written to the
diagnostics buffer
Tip:
Always program OB86 when you commission the CPU. This allows you to detect and
analyze interruptions in the data transfer.
