Omron Programmable Terminals NT31 NT31C - Manual (Page 105)

5-1 Section Connecting to the Host’s RS-232C Port
94
The relay terminal board is not included in the figure below. Insert a relay termi-
nal board so as to achieve the wiring configuration indicated below.
RS-485
NT31/NT31C Host
NT-AL001
1
14
13 25
7
5
3
1
8
6
4
2
NT31/NT31C side
Next PT
NT-AL001 side
Shielding wire
(25-pin type)
Abbreviation
FG
−
SD
RD
RS
CS
−
SG
−
TRM
RDB (+)
SDB (+)
−
−
−
SDA ( −)
RDA ( −)
−
−
RSB (+)
RSA ( −)
−
Pin number
Connector
hood
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
−
23
24
25
Pin number
6
5
4
3
1
Abbreviation
RDA
RDB
SDA
SDB
Functional
ground
RS-232C/
422A/485
connector
RS-422A
terminal
block
In order to avoid an FG ground loop, do not make the connections between the
functional ground of the NT-AL001 and the shielding.
Connecting an
NT31/NT31C and
NT-AL001 (RS-485)