Setup Area Allocations (Modbus-Rtu Slave Mode); Setup Area Words - Omron SYSMAC CS1W-SCB41-V1 Operation Manual

Setup Area Allocations (Modbus-RTU Slave Mode)

Note
9-2 Setup Area Allocations (Modbus-RTU Slave Mode)
9-2-1

Setup Area Words

The Modbus-RTU command that access a specific Modbus data model is
used to read and write I/O memory areas in the CS/CJ-series CPU Unit.
CS/CJ-series CPU Unit
I/O Memory
CIO Area 0
1
2
:
Work Area 0
1
2
:
Holding Area 0
1
2
:
DM Area 0
1
2
:
EM Area
0
1
DM Area settings are used to
2
allocate the area for each data
:
model except for discrete inputs.
Refer to 9-2 Setup Area Allocations (Modbus-RTU Slave Mode) for the DM
Area settings to allocate areas. Refer to 9-3-4 Command and Response
Details for details on Modbus-RTU commands.
1. DM Area settings are read when the power is turned ON to the CPU Unit,
when the Serial Communications Board/Unit is restarted, or when the port
is restarted. Always cycle the power to the CPU Unit or restart the Serial
Communications Board/Unit or port after changing the settings.
2. Addresses in Modbus data models start from 1, but addresses specified in
Modbus-RTU commands and addresses in the CS/CJ-series CPU Unit
start from 0. To access address 0 in an area allocated in the CS/CJ-series
CPU Unit, specify address 100 in the Modbus-RTU command.
This section describes the Setup Area allocated to the Serial Communications
Board and Serial Communications Units in the DM Area when Modbus-RTU
slave communications are used.
The Serial Communications Board and Serial Communications Units use the
following words as a Setup Area in the DM Area when Modbus-RTU slave
communications are used. The words allocated to the Serial Communications
Board are different from those allocated to the Serial Communications Units
(which are allocated words according to the unit numbers).
Modbus Data Models
Discrete Inputs 1
2
3
:
Coils 1
2
3
Modbus Commands
:
Input Registers 1
2
3
:
Holding Registers 1
2
3
:
Section 9-2
Modbus-RTU command
Read Coils
Read Discrete Inputs
Read Holding Registers
Read Input Registers
Write Single Coil
Write Single Register
Write Multiple Coils
Write Multiple Registers
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