Event Recognition For Cpus 31X-2 Dp/31Xc-2 Dp As The Dp Slave - Siemens SIMATIC S7-300 Hardware And Installation Manual

Commissioning
Recognizing the Operating State of the DP master (Event Recognition)
The table below shows how CPU 31x-2 DP/31xC-2 DP as DP slave recognizes
operating mode transitions or data exchange interrupts.
Table 9-9
Event
Bus failure interrupt
(short-circuit,
connector
unplugged)
DP master.
6723
RUN
DP master
581
STOP
Tip:
When commissioning the CPU as DP slave, always program OB 82 and 86. This
helps you to recognize and evaluate the respective operating states or data
exchange errors.
Programming, status/control via PROFIBUS
As an alternative to the MPI interface, you can program the CPU or execute the
PG's status and control functions via the PROFIBUS-DP interface. To do so, you
must enable these functions when configuring the CPU as a DP slave in STEP 7.
This is not required for CPU 300C.
Note
The use of Status and Control function via the PROFIBUS-DP interface extends
the DP cycle.
Data Transfer via Intermediate Memory
CPU 31x-2 DP/31xC-2 DP as DP slave provides an intermediate memory for
PROFIBUS DP communication. All data exchange between the CPU as DP slave
and the DP master takes place via this intermediate memory. You can configure up
to 32 address areas for this function.
9-32

Event recognition for CPUs 31x-2 DP/31xC-2 DP as the DP slave

What happens in the DP slave?
•
Call of OB86 with the message Station failure
(coming event; diagnostic address of the DP slave, assigned to
the DP slave)
•
with I/O access: Call of OB122
(I/O access error)
•
Call of OB82 with the message Module error
(coming event; diagnostic address of the DP slave, assigned to
the DP slave; Variable OB82_MDL_STOP=1)
•
Call of OB82 with the message Module OK
(outgoing event; diagnostic address of the DP slave, assigned to
the DP slave; Variable OB82_MDL_STOP=0)
S7-300 Programmable Controller Hardware and Installation
A5E00105492-02