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MELSEC-Q
7 PARAMETER SETTING
7.4 MODBUS
®
Device Assignment Parameters
Using MODBUS
R
device assignment parameters, the MODBUS
R
devices are
correlated with the programmable controller CPU device memory.
This allows direct access from the MODBUS
R
compatible master device to the
programmable controller CPU device memory.
D300
D299
400499
D300
400500
D301
400501
1234
H
Ethernet
R
R
R
Programmable
controller CPU
Sequence program
unnecessary
Device memory
Device memory
MODBUS device assignment parameters
QJ71MT91 (Slave function)
MODBUS device
Request message (holding register 400500 read request)
Response message (holding register 400500 = 1234
H
)
MODBUS /TCP
master device