Omron NT631 Operation Manuals page 114

Connecting to the Host's RS-232C Port
Connection between NT631/NT631C Units (RS-422A)
106
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.
NT631/NT631C
RS-422A
:
RDA NT631/NT631C side
TRM
RDB
SDA
SDB
RSA
RSB
24V
+DC
* Short TRM and RDA terminals of the NT631/NT631C at the end of the RS-422A
cable ( marked in the above figure) using the short-circuit tool supplied with the
:
NT631/NT631C.
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
Short-circuit tool
Abbreviation
:
RDA (−)
TRM
RS-422A
RDB (+)
/485
SDA (−)
terminal
block
SDB (+)
RSA (−)
RSB (+)
Functional
Shielding
ground
wire
Section 5-1
NT631/NT631C side
Abbreviation
RDA (−)
TRM
RS-422A
RDB (+)
/485
SDA (−)
terminal
SDB (+) block
RSA (−)
RSB (+)
Functional
ground
RDA
TRM
RDB
SDA
SDB
RSA
RSB
24V
+DC