
5 Serial Gateway
5-26
CJ-series Serial Communications Units Operation Manual for NJ-series CPU Unit(W494)
Note
Be sure to connect a terminating resistance of between 100 and 125
Ω
(1/2W) to the terminals
of the remote devices at either end of the RS-422A/485 transmission path. (Set the terminat-
ing resistance on this Unit by using Terminating resistance ON/OFF switch located on the
front panel of the Unit.
It is possible to access Modbus-RTU Slave-compatible devices (including OMRON inverters) that are
connected to a PLC via a serial network (Modbus-RTU) from a PLC or PT by sending Modbus-RTU
commands.
•
Sent message: command code 2804 hex + Modbus-RTU command
•
Message after conversion: Modbus-RTU command
Examples of Modbus-RTU Slave OMRON Devices
1:N RS-485 Connection Example Using RS-422A/485 Port
5-4-4
Converting to Modbus-RTU
Type
Model series
Inverters
3G3MX2
3G3RX
3G3JX
Temperature Controllers
E5CN
EJ1
1
2
3
4
5
RDA
RDB
SDA
SDB
FG
A(
−
)
B(+)
A(
−
)
B(+)
Terminal block connector
RS-422A/
485 Inter-
face
Serial Communications Unit
Pin
Signal
RS-422A/
485 Inter-
face
RS-422A/
485 Inter-
face
Signal
Signal
Device that supports
RS-422A/485
communications
(2-wire)
Device that supports
RS-422A/485
communications
(2-wire)
Header
Modbus-RTU command
2804
(Via network or CPU bus)
Modbus-RTU command
Modbus-RTU command
(RS-232C or RS-422A/485)
CPU Unit (Send-
Cmd instruction)
or PT (Program-
mable Terminal)
Modbus-RTU command encapsulated using
command 2804 hex
Serial Communi-
cations Unit
Modbus-RTU
Slave-
compatible
device
(OMRON
Inverter, etc.)
Содержание CJ1W-SCU22
Страница 192: ...4 Using Protocol Macros 4 56 CJ series Serial Communications Units Operation Manual for NJ series CPU Unit W494...
Страница 250: ...6 No protocol Mode 6 22 CJ series Serial Communications Units Operation Manual for NJ series CPU Unit W494...
Страница 460: ...A Standard System Protocol R 126 CJ series Serial Communications Units Operation Manual for NJ series CPU Unit W494...
Страница 473: ...Index 1 CJ series Serial Communications Units Operation Manual for NJ series CPU Unit W494 I Index...