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MELSEC-Q
5 FUNCTIONS
5.2.2 Dedicated instructions
Used in a sequence program to read/write the MODBUS
R
device data, etc. at any
timing.
[Z.MBRW ]
Command
MODBUS /TCP slave device
Holding register
Programmable
controller CPU
QJ71MT91
Device memory
1234
H
1234
H
400500
(Master function)
Ethernet
R
Request message
(holding register 400500 read request)
Response message
(holding register 400500 = 1234
H
)
Dedicated instruction list
The list of the dedicated instructions supported by the QJ71MT91 is indicated
below.
Dedicated
Instruction
Description Reference
MBRW
Issues a MODBUS
R
device read/write request message to
the slave.
Section 10.2
MBREQ
Communicates with the slave in the request message
format of any PDU (protocol data unit).
Section 10.3