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10
DEDICATED INSTRUCTIONS
Function
code
Function
Read head holding
code
register number
(17
)
(2AF7
)
H
H
(H)
(L)
10 - 10
REMARK
The MODBUS/TCP frames used in communication with the slave in this sample
program are as shown below.
Request message format (Master (QJ71MT91)
Read points
Write head holding
n
register number
(0064
)
(01F3
H
(H)
(L)
(H)
Response message format (Slave
Function code
Function code
Number of bytes
(17
)
n 2
H
(C8
)
H
Data
Write points
Number
m
of bytes
)
(0020
)
m 2
H
H
(0040
(L)
(H)
(L)
Master (QJ71MT91))
Read device data
1
(411000 value)
(H)
(L)
MELSEC-Q
Slave)
Write device data
1
(W0000 value)
)
H
(H)
(L)
(Number of bytes m 2)
Data
Read device data
(411099 value)
(H)
(Number of bytes n 2)
Write device data
m
(W001F value)
(H)
(L)
n
(L)
10 - 10
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