Download D397_21_880 TIC Controller User Manual issue E

Instrument Controller
PAGE
15
INSTALLATION
Figure 10 - IBM PC RS232 interface - 9-way
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
Figure 12.
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
Dec 05
15
Issue E