Omron NT31 Operation Manuals page 118

Connecting to the Host's RS-232C Port
Connection between NT31/NT31C Units (RS-422A)
1
13
The relay terminal board is not included in the figure below. Insert a relay terminal
board so as to achieve the wiring configuration indicated below.
NT31/NT31C
RS-422A
:
14
NT31/NT31C side
Abbreviation Pin number
Connector
FG
hood
−
1
SD 2
RS-232C/
422A/485 RD 3
connector
RS 4
CS 5
−
6
SG 7
−
8
TRM 9
RDB (+) 10
RDB (+) 11
−
12
−
13
−
14
25
SDA (−) 15
16
RDA (−)
−
− −
RSB (+) 23
RSA (−) 24
−
25
(25-pin type)
* Make the connection between pin numbers 9 and 10 at the terminal NT31/NT31C
(marked " " in the figure above) only.
:
In order to avoid an FG ground loop, make the connection between the connector
hood and the shielding at one side only.
Host
NT-AL001
NT31/NT31C side
Pin number
Shielding wire
Connector
hood
1
2
3
4
5
6
7
8
:
9
10
11
12
13
14
15
16
−
23
24
25
Section 5-1
1
Abbreviation
FG
−
SD
RS-232C/
RD 422A/485
connector
RS
CS
−
SG
−
TRM
RDB (+)
RDB (+)
−
−
−
13
SDA (−)
RDA (−)
−
−
RSB (+)
RSA (−)
−
(25-pin type)
14
25
107