Siemens CPU 312C Hardware And Installation Guide

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S7-300 Automation System, Hardware and Installation: CPU 31xC and CPU 31x
A5E00105492-03
9-25
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The table below shows how the DP CPU operating as a DP master recognizes
operating mode transitions of a CPU operating as a DP slave or data exchange
interruptions.
Table 9-8 Event recognition by CPUs 31x-2 DP/31xC-2 DP as the DP master
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Bus failure interrupt
(short-circuit,
connector
unplugged)
• Call of OB86 with the message 6WDWLRQIDLOXUH
(coming event; diagnostic address of the DP slave assigned to
the DP master)
• with I/O access: Call of OB122
(I/O access error)
DP slave:
RUN → STOP
• Call of OB82 with the message 0RGXOHHUURU
(incoming event; diagnostic address of the DP slave assigned to
the DP master; Variable OB82_MDL_STOP=1)
DP slave:
STOP → RUN
• Call of OB82 with the message 0RGXOH2.
(outgoing event; diagnostic address of the DP-Slave assigned to
the DP master; Variable OB82_MDL_STOP=0)
7LS:
When commissioning the CPU as DP master, always program OB82 and OB86.
This helps you to recognize and evaluate data exchange errors or interruption.
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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.
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The use of Status and Control function via the PROFIBUS-DP interface extends
the DP cycle.
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As of 67(3 V 5.x you can configure equidistant lengths for PROFIBUS subnet
(constant bus cycle time) bus cycles. Details on constant bus cycle time are found
in the 6WHS2QOLQH+HOS.

Siemens CPU 312C Specifications

General

Brand	Siemens
Model	CPU 312C
Category	Processor
Language	English