R-39
A Standard System Protocol
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
R
-2
Com
p
o
W
a
y
/F Mast
er Pr
otoc
o
l
Re
f
R
-2-9
Connections
RS-422 4-wire Connections
•
RS-422 connections can be one-to-one, or one-to-N when a 3G2A9-AL001 Link Adapter is
used. A maximum of 32 Serial Communications Boards and Unit can be connected in one-to-
N systems.
•
The total cable length can be 500 m max.
•
Use shielded, twisted-pair cable.
•
Be sure to turn ON the terminating resistance switches only at the device at each end of the
transmission line.
CJ1W-SCU
@
1-V1
CJ1W-SCU
@
2
RS-485 2-wire Connections
•
RS-485 connections can be one-to-one or one-to-N. A maximum of 32 Serial Communica-
tions Units/Boards can be connected in one-to-N systems.
•
The total cable length can be 500 m max.
•
Use shielded, twisted-pair cable.
•
Be sure to turn ON the terminating resistance switches only at the device at each end of the
transmission line.
RS-422
Abbreviation
Shell
Ab-
brevi-
ation
Pin
No.
Shielded wire
Intelligent Signal
Processor
220
Ω
220
Ω
SN751177N or equivalent
The terminating resistance (220
Ω
) is set with the terminal block switch.
Terminal
block switch
Serial Commu-
nications Board/Unit
6
8
1
2
Set the 2-/4-wire switch
to the 4-wire setting.
Turn ON the terminat-
ing resistance switch.
Shielded wire
RS-422
Intelligent Signal Processor
Abbreviation
SDA
SDB
RDA
RDB
SG
Pin
No.
9
5
6
1
3
Serial Communications Board/Unit
RS-422
Abbreviation
RDA
RDB
SDA
SDB
FG
1
2
3
4
5
The terminating resistance (220
Ω
) is set
with the terminal block switch.
220
Ω
Terminal
block switch
SN751177N
or equivalent
6.8V
220
Ω
Set the 2-/4-wire switch
to the 4-wire setting.
Turn ON the terminating
resistance switch.