103BCommunication
10.3 PROFIBUS
S7-1200 Programmable controller
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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. In the figure below, the S7-1200 is a DP slave to an S7-300
controller.
The S7-1200 is connected to a PROFIBUS network as a DP master with the CM 1243-5
communication module. The CM 1243-5 (DP master) module can be the communications
partner of DP V0/V1 slaves. In the figure below, the S7-1200 is a master controlling an
ET200S DP slave.
If a CM 1242-5 and a CM 1243-5 are installed together, an S7-1200 can perform as both a
slave of a higher-level DP master system and a master of a lower-level DP master system,
simultaneously.