5. External connections
5.5 Serial interfaces for communication with PLCs or devices
5.5.2.2 RS-485 topology
l
A bus segment can interconnect up to 32 slaves.
l
Several bus segments can be connected using repeaters (bi-directional amplifiers).
The use of repeaters enables the maximum cable length to be
increased.
For more details, please consult the documentation provided by man-
ufacturer.
A bus segment must be provided with cable termination (120 Ohm) at both ends.
These terminals must be connected in the plug directly between pin 3 and 7.
The bus segment must be terminated at both ends.
No more than two terminations must be provided for each bus segment.
Operation without correct cable termination can cause transfer errors.
Figure 29: Bus segment with four nodes
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XV300
12/15 MN048017 EN www.eaton.eu
