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

Recognizing the operating state of DP slaves (Event recognition)
The table below shows how CPU 31x-2 DP/31xC-2 DP as DP master recognizes
operating mode transitions of a CPU as DP slave or data exchange interrupts.
Table 9-8
Event
Bus failure interrupt
(short-circuit,
connector
unplugged)
DP slave:
6723
RUN
DP slave:
581
STOP
Tip:
When commissioning the CPU as DP master, always program OB 82 and 86. This
helps you to recognize and evaluate data exchange errors or interruption.
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.
Note
The use of Status and Control function via the PROFIBUS-DP interface extends
the DP cycle.
Equidistance
As of STEP 7 V 5.x you can configure equidistant lengths for PROFIBUS subnet
bus cycles. Details on equidistance are found in the Step 7 Online Help.
S7-300 Programmable Controller Hardware and Installation
A5E00105492-02

Event recognition by CPUs 31x-2 DP/31xC-2 DP as the DP master

What happens in the DP master?
•
Call of OB86 with the message Station failure
(coming event; diagnostic address of the DP slave assigned to
the DP master)
•
with I/O access: Call of OB122
(I/O access error)
•
Call of OB82 with the message Module error
(incoming event; diagnostic address of the DP slave assigned to
the DP master; 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 master; Variable OB82_MDL_STOP=0)
Commissioning
9-29