D397-01-880 Issue E
Page 16
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Installation
Figure 11 - IBM PC RS232 interface - 25-way
3.3.5.2
Connecting RS485
RS485 provides the TIC with the capability to be networked with other TICs and a host PC as shown in
CAUTION
All of the ground connections are tied together. If differences exist in the local ground voltage, damage could
occur. If the TICs being networked are liable to experience different ground potentials, a suitable RS485 isolator
should be connected between them.
Use shielded cable for the interface to reduce interference problems and limit the length of the RS485 link to less
than 1000 metres.
Long links may require the addition of 120
Ω
terminating resistors at each end of the link to improve communications
reliability.
Figure 12 - RS485 TIC network