ABB C1900 Installation Manual page 5

COMMANDER 1900
Linked Out
4
9
3
Links on Serial Module
Note. If an RS422/485 adaptor card without pull-up and pull-down resistors is used, the COMMANDER 1900's
internal resistors must be linked out.
Fig. 2.2 Pull-up and Pull-down Resistors (5-wire Operation)
Serial Module
Terminal Board
1
2
3
Tx+
4
Tx–
5
Rx–
6
Rx+
7
8
GND
9
2 ELECTRICAL INSTALLATION...
Computer Terminal or Host Computer
1.8kΩ Pull-down
Resistor
0V
+5V
1.8K Pull-up
Resistor
GND
0V
1.8kΩ Pull-down
Resistor
0V
'A'
'B'
+5V
1.8kΩ Pull-up
Resistor
'B'
'A'
3