Omron NT631 Operation Manuals page 141

Connecting to the Host's RS-422A/485 Port
S Wiring when connecting CPM1, SRM1
Applicable units:
CPM1-10CDR-j
CPM1-30CDR-j
CPM1A-10CDj-j
CPM1A-30CDj-j
SRM1-C02-V1
In order to avoid an FG ground loop, do not connect the functional ground of the
NT631/NT631C to the shielding of the RS-422A cable.
RDA
NT631/NT631C side
TRM
Short-circuit tool
Abbreviation
RDA (−)
RDB
TRM
SDA
RDB (+)
RS-422A/
485 SDA (−)
SDB
connector
SDB (+)
RSA
RSA (−)
RSB (+)
RSB
Functional
ground
24V
+DC
Section 5-2
CPM1-20CDR-j
CPM1A-20CDj-j
CPM1A-40CDj-j
PLC side
Abbreviation
Shielding wire
FG
SG
RS-422A
SDB (+)
terminal
SDA (−) block
RDB (+)
RDA (−)
(9-pin type)
FG
SG
SDB
SDA
RDB
RDA
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