Omron Programmable Terminals NT31 NT31C - Manual (Page 100)

5-1 Section Connecting to the Host’s RS-232C Port
89
Connecting an NT31/NT31C and NT-AL001 (RS-422A)
RS-422A
NT31/NT31C Host
NT-AL001
NT31/NT31C side
1
14
13 25
7
5
3
1
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
8
6
4
2
RS-232C/
422A/485
connector
RS-422A
terminal
block
In order to avoid an FG ground loop, do not make the connection between the
functional ground of the NT-AL001 and the shielding.
Connecting an NT31/NT31C and NT-AL001 (RS-485)
RS-485
NT31/NT31C Host
NT-AL001
NT31/NT31C side
1
14
13 25
7
5
3
1
8
6
4
2
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 connection between the
functional ground of the NT-AL001 and the shielding.
Reference: When using RS-485 as a port for the NT31/NT31C, only NT link (1:N) method
(standard or high-speed) can be used.