Mitsubishi QJ71MT91 User Manual

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MELSEC-Q
1 OVERVIEW
(2) Supporting slave function of MODBUS
R
/TCP communication
The QJ71MT91 supports the slave function of MODBUS
R
/TCP communication,
which is an open network system for factory automation, and it is compatible with
various MODBUS
R
/TCP master devices (hereafter abbreviated to the masters)
of other manufacturers.
The slave function supports the following two functions.
(a) Automatic response function
The QJ71MT91 can automatically respond to a request message received
from the master.
A sequence program for the slave function is not needed.
(b) MODBUS
R
device assignment function
Using MODBUS
R
device assignment parameters, the MODBUS
R
devices
are correlated with the programmable controller CPU device memory.
This enables direct access from the master to the programmable controller
CPU device memory.
Supporting the MODBUS
R
devices of large capacity, the QJ71MT91 allows
all device memories of the programmable controller CPU to be assigned.
Programmable
controller CPU
D300
MODBUS
device assignment parameters
MODBUS device
D299
Device memory
400499
D300 400500
D301 400501
Device memory
1234
H
Response message (holding register 400500 = 1234
H
)
Request message (holding register 400500 read request)
QJ71MT91(Slave function)
Ethernet
R
R
R
Sequence program
not needed
MODBUS /TCP
master device

Mitsubishi QJ71MT91 Specifications

General

Brand	Mitsubishi
Model	QJ71MT91
Category	Controller
Language	English