Omron NT31 Series, Operation Manuals

Page: 151 / 707

140
Connecting to the Host’s RS-422A/485 Port
Section 5-2
Connecting between NT31/NT31C Units
The relay terminal block is not included in this figure. Insert the relay terminal block
so as to achieve the wiring configuration shown below.
RS-422A
NT31/NT31C Host
1
14
13 25
1
14
13 25
NT31/NT31C side
Shielding wire
(25-pin type)
Abbreviation
FG
−
SD
RD
RS
CS
−
SG
−
TRM
RDB (+)
RDB (+)
−
−
−
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
RS-232C/
422A/485
connector
RS-232C/
422A/485
connector
Abbreviation
FG
−
SD
RD
RS
CS
−
SG
−
TRM
RDB (+)
RDB (+)
−
−
−
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
(25-pin type)
NT31/NT31C side
* Make the connection between pin numbers 9 and 10 at the NT31/NT31C at the end
of the RS-422A cable (marked “
” in the figure above) only.
In order to avoid an FG ground loop, connect the functional ground of only one of
the NT31/NT31C units to the shielding of the RS-422A cable.