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Protocol Conversion Section 6-5
System Configuration Patterns
Sending FINS Messages Using CMND(490) in CPU Unit’s Ladder Program
The Board/Unit converts the FINS messages to Modbus-RTU protocol for
sending in this operation.
Access from CPU Unit (on the Same PLC)
Access from CPU Unit (on Network PLC)
CPU Bus-to-Serial Details Routing tables to
treat serial
communications
path as network
OMRON Inverters connected serially to
the Serial Communications Board/Unit
using Modbus-RTU can be accessed
from a CPU Unit in the same PLC.
Optional
2804
Serial Communications Unit/Board
CPU Unit
FINS header
CMND(490)
FINS message
RS-485 (Modbus-RTU)
Protocol
conversion
Modbus-RTU
command
Modbus-RTU
command
Modbus-RTU
Slave device
(e.g, OMRON
Inverter)
FINS message-to-Serial Details Routing tables
to treat serial
communications
path as network
OMRON Inverters connected serially to
the Serial Communications Board/Unit
using Modbus-RTU can be accessed
from a CPU Unit in a PLC connected to
the network.
Optional
2804
CMND(490)
FINS header
CPU Unit
Serial Communications Unit/Board
RS-485 (Modbus-RTU)
FINS message
Modbus-RTU
command
Modbus-RTU
command
Protocol
conversion
Network (Ethernet,
Controller Link,
DeviceNet)
Modbus-RTU
Slave device
(e.g, OMRON
Inverter)