Siemens SIMATIC CP 440 Manual page 41

Slave
Figure 2-10
In the case of a topology in RS485 operation:
– The cable pair is interconnected for the send/receive line of all the nodes.
– Only the receiver of a node has a default setting. All the other modules
function without default settings.
Slave
Figure 2-11
The settings required for the different topologies can be made in the
parameterization interface in the "Interface" dialog box.
Point-to-point connection CP 440 Installation and Parameter Assignment
A5E00057742-02
RS 422 Multipoint
RS 485 Multipoint
Basic Principles of Serial Data Transmission
Master
Slave
Master
Slave
Slave
Slave
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