PC3000 Complete Installation guide iss 12 - Elektro-Trading

Notes:
PC3000 - Installation Guide iss. 3.2
Intelligent Communications Module
1. All PC3000 cables supplied by Eurotherm do not swap the receive
and transmit pairs. Where these cables are used to connect from one
PC3000 to another it will be necessary to introduce a swap on one end
of point to point connections or the master connection of Master-Slave
connections. This can be done either by using links LKA5-8 (port A
only) or external to the ICM on terminal block assemblies. For further
details of cabling options please refer to the section on cabling in the
PC3000 installation handbook.
2. Termination resistor(s) should be fitted to both ends of the cable used
for RS485 connections. All other connections to the cable should not
be terminated. Correct termination is particularly important when
cable lengths are long. A ‘4-wire’ cable can be terminated by
connecting a 120Ω resistor between Rx+ and Rx- for each end.
A ‘2-wire’ cable can be terminated by connecting a 120Ω resistor
between Rx/Tx+ and Rx/Tx- at each end.
More detail on how to connect termination resistors is shown in the section on
communication configuration links.
Multi-drop communications should not be connected together in a star or other non
chain configuration.
Master
✔
Daisy chained wiring
Short drop
connection to
the trunk wiring
Master Slaves............
Slaves............
✖
18-7