IDTECK iTDC EIO8 Quick Installation Manual page 12

※ iTDC Quick Installation Guide
Caution
○
Recommended Communication Cable
1
It is recommended to use STC(Shielded Twisted Pair) cable for RS422 communication.
○
GND Connection
2
As the figure above, connect an end of Shield wire to the Power terminal block(GND) of iTDC/iTDC-SR. If you
connect both ends of Shield wire to the Power terminal block(GND) of iTDC/iTDC-SR, currents may flow
because voltage levels of both sides are different then it causes communication error. Thus, must connect
only one end of the Shield wire as the figure above.
○
Termination Resistor Connection
3
When you connect RS232/RS422 Converter and iTDC/iTDC-SR, connect Termination Resistor to the start
and end points of the wire as the figure above. If the length of communication wire is too long in one
communication loop, it causes communication problem from the cracked data or decrement. To prevent it,
connect Termination Resistor as the figure above. But, don't use Termination Resistor for short-distance
communication wire. If you use Termination Resistor in short-distance, it could cause communication errors.
(Figure: RS422 Multiple Connection Using TCP/IP Module)
12
Mar.11.2010