30
6K Hardware Installation Guide
RS-485 Communication
RS-232 Connector
Pin Outs for RS-485 Communication
Pin Description
1
Rx + (also called RD B)
4
Tx + (also called TD B)
6
GND (isolate ground)
7
Rx – (also called RD A)
8
Tx – (also called TD A)
•
Maximum RS-485 cable length is 4000 feet (1220 meters).
•
To establish unique addresses for multi-drop units, use the
ADDR
command.
•
Use termination resistors at both ends of the multi-drop. Keep
stubs as short as possible.
•
Recommended cables: 2-wire: Belden 9841
4-wire:
Belden
9842
•
Refer to the diagrams below (or page 5) for necessary DIP
switch settings for 2-wire and 4-wire configuration.
4-Wire Connections (plus ground):
www.comoso.com