Setting The Terminal Resistance For Rs-422A/485 Communications - Omron Programmable Terminals NT31 NT31C Setup Manual

Connecting to the Host's RS-232C Port

5-1-5 Setting the Terminal Resistance for RS-422A/485 Communications

Name Model
XM2A-2501
Connector
DB-25P F-N
XM2S-2511
Connector Connector
hood
DB-C2-J9
Cable TKVVBS4P-03
1.25-N3A
(fork type)
Crimp Crimp
terminals
Y1.25-3.5L
(fork type)
The terminal screws of the NT-AL001 are M3 specification. When wiring,
use crimp terminals for M3 use. Tighten terminal screws with a tightening
torque of 0.5 N@m.
Note Always use crimp terminals for wiring.
Examples of applicable terminals
6.2 mm or less
The serial port B connector of the NT31/NT31C has a terminal resistance setting
terminal (TRM).
In RS-422A/485 communications, a terminal resistor must be set at the device at
the end of the communication cable, but not at any other device.
The NT31/NT31C has a built-in terminal resistor, and whether or not the terminal
resistance is applied is set by the wiring at the terminal resistance setting termi-
nals (pins No. 9 and 10 of serial port B). The terminal resistance is 120 Ω. When
carrying out RS-422A/485 communications using serial port B, short between
terminals No. 9 and 10 at the NT31/NT31C at the end of the RS-422A/485 cable.
Leave terminals No. 9 and 10 open at NT31/NT31C units other than the one at
the end of the cable.
When not using RS-422A/485 communications, the terminal resistance setting
is ineffective.
Maker
Delivered with the following
25-pin type
units:
Made by OMRON
C500-LK203
Delivered with the following
units:
25-pin type
3G2A6-LK201-EV1
Made by JAE
3G2A5-LK201-EV1
Delivered with the following
25-pin type
units:
Made by OMRON
C500-LK203
Delivered with the following
units:
25-pin type
3G2A6-LK201-EV1
Made by JAE
3G2A5-LK201-EV1
Tachii Electric
Wire Co., Ltd.
Japan Solderless
Recommended cable size:
Terminal MFG
AWG22 t 18 AWG22 to 18
(0.3 to 0.75 mm
Molex Inc.
Fork type
6.2 mm or less
Section 5-1
Remarks
2
)
Round type
99