Diagnostics; Distributed I/O Instructions; Diagnostic Instructions; Diagnostic Events For Distributed I/O - Siemens S7-1200 System Manual

10.2.8

Diagnostics

Refer to "Organization blocks (OBs)" (Page 85) for information on how to use organization
blocks (OBs) for diagnostics with these communication networks.
10.2.9

Distributed I/O instructions

Refer to "Distributed I/O (PROFINET, PROFIBUS, or AS-i)" (Page 314) for information on
how to use the distributed I/O instructions with these communication networks.
10.2.10

Diagnostic instructions

Refer to the "Diagnostics (PROFINET or PROFIBUS)": "Diagnostics instructions" (Page 345)
for information on how to use these instructions with these communication networks.
10.2.11

Diagnostic events for distributed I/O

Refer to the "Diagnostics (PROFINET or PROFIBUS)": "Diagnostics events for distributed
I/O" (Page 345) for information on how to use this diagnostic information with these
communication networks.
10.3

PROFIBUS

A PROFIBUS system uses a bus master to poll slave devices distributed in a multi-drop
fashion on an RS485 serial bus. A PROFIBUS slave is any peripheral device (I/O
transducer, valve, motor drive, or other measuring device) which processes information and
sends its output to the master. The slave forms a passive station on the network since it
does not have bus access rights, and can only acknowledge received messages, or send
response messages to the master upon request. All PROFIBUS slaves have the same
priority, and all network communication originates from the master.
A PROFIBUS master forms an "active station" on the network. PROFIBUS DP defines two
classes of masters. A class 1 master (normally a central programmable controller (PLC) or a
PC running special software) handles the normal communication or exchange of data with
the slaves assigned to it. A class 2 master (usually a configuration device, such as a laptop
or programming console used for commissioning, maintenance, or diagnostics purposes) is
a special device primarily used for commissioning slaves and for diagnostic purposes.
The S7-1200 is connected to a PROFIBUS network as a DP slave with the CM 1242-5
communication module. The CM 1242-5 (DP slave) module can be the communications
partner of DP V0/V1 masters. If you want to configure the module in a third-party system,
there is a GSD file available for the CM 1242-5 (DP slave) on the CD that ships with the
module and on Siemens Automation Customer Support
(http://support.automation.siemens.com/WW/llisapi.dll?func=cslib.csinfo&lang=en&objid=6G
K72425DX300XE0&caller=view) pages on the Internet.
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
Communication
10.3 PROFIBUS
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