Omron SYSMAC CJ1W-SCU31-V1

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Protocol Conversion Section 6-5
1:N RS-485 Connection Example Using RS-422A/485 Port
Note Be sure to connect terminating resistance of between 100 and 125 Ω (1/2 W)
to the terminals of the remote devices at either end of the RS-422A/485 trans-
mission path. (Set the terminating resistance on the Board/Unit by turning
ON/OFF the Terminating Resistance Switch.)
6-5-4 Converting FINS to Modbus-RTU
Modbus-RTU Slave-compatible devices (including OMRON Inverters) con-
nected serially to a PLC via Modbus-RTU can be accessed from the PLC or
PT using Modbus-RTU commands enclosed in FINS messages.
• Sent FINS message: FINS header + FINS command code 2804 hex +
Modbus-RTU command
• Message after conversion: Modbus-RTU command
Modbus-RTU Slave-compatible OMRON Devices
Serial Communications Board/Unit
Pin No.
Shell
D-Sub 9-pin (cable connector type: Male)
Signal
name
RS-422A/485
interface
Component with RS-422A/485
communications function
(2-wire method)
Signal
name
RS-422A/485
interface
Component with RS-422A/485
communications function
(2-wire method)
Signal
name
RS-422A/485
interface
Type Model series
Inverters 3G3JV
3G3MV
3G3RV
Temperature Controllers E5CN (New version)
FINS header
Modbus-RTU command
2804
(Via network or CPU bus)
Modbus-RTU command
Modbus-RTU command
(RS-232C or RS-422A/485)
CPU Unit
(CMND(490)
instruction) or
PT (Program-
mable Termi-
nal)
Modbus-RTU command encapsulated
using FINS command 2804 hex
Serial Com-
munications
Unit/Board
Modbus-RTU
Slave-
compatible
device
(OMRON
Inverter, etc.)