Wiring the Network and Connecting the Computer

2-3

2.2.3 RS-485 Network

If your computer is equipped with an RS-485 interface, connect to the controller network

in accordance with the instructions provided with that option card.

If you plan to use a serial (COM) port to connect to your network, install an RS-232-to-

RS-485 converter on the port (see diagram below). A suitable converter is available from

Omega.

* Converter is supplied with a wallplug-mounted power
transformer.

RS-485 Communication:

One-to-many connection between an RS-232 port (with converter) and multiple

controllers; if the computer has an RS-485 port, no converter is needed

11
1
2
3
4
5
6
7
8
9
10

(B) (A)

14
12
13
Wire directly to screw terminals on
converter. B on converter goes to A
on unit, A on converter goes to B
RD(B)
RD(A)
TD(B)
TD(A)
To
Controller
Terminal 13
To
Controller
Terminal 14(A)

(B)

GND
+12 V
Up to 2000 ft
RS-232/RS-485 converter;
Omega part number
223A001U01*
Computer
RS-232
port
Data cable assembly DB 9 to
DB 25, or DB 9 to DB 9
de
p
endin
g
on
y
our com
p
uter
Other controllers