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MELSEC-Q
1 OVERVIEW
3) It is possible to access the control PLC and non-control PLCs using the
MC protocol and through GX Developer from the external device.
In addition, data communication with the control PLC of the Q series C24
can be performed using the non procedure/bidirectional protocol.
(Example) When communicating with the MC protocol
Non-control PLC
Control PLC
Q series C24
Specify the QCPU to be
accessed by the I/O number
of the requested module.
External
device
Command message
transmitted using a
QnA compatible 4C
frame
03FF
H
03E0
H
to 03E3
H
Device memory, etc.
Data
Response message
Communication using the
MC protocol (read/write)
Device memory, etc.
Data
If the MC protocol, GX Developer is used to access other stations, it is
possible to access the control PLC and non-control PLCs of the station to
be accessed even if the relay station and the accessed station are
multiple CPU systems.
(Example)
MELSECNET/H
1) : PLC No.1
2) : PLC No.2
3) : PLC No.3
4) : PLC No.4
1
: Module used for routing, controlled
by PLC No.1
: Q series C24 controlled by
PLC No.1
: Module used for routing, controlled
by PLC No.2
1'
2
Local station
Relay station
External device
Communication throu
h GX Develope
Communication using the MC protocol
Setting from GX Developer
Peripheral device
MELSECNET/H
Station to be accessed
1 2
1'
1) 2) 3) 4)
2 21) 2) 3) 4)
21) 2) 3) 4)
It is possible to access other stations re
ardless
of whether the control PLC of the module to be
routed through is the same or different.
The modules used for the routing are MELSECNET/H network modules
The QnA compatible 4C frame should be performed for access to non-
control PLCs when communicating using the MC protocol.
However, the available functions differ depending on the QCPU to be
accessed (whether it is a control PLC or a non-control PLC).
See the Reference Manual for the available functions and accessible range.
A module used for routing can access the following modules when
accessing other stations:
• MELSECNET/H, MELSECNET/10 network module
• Q series C24 • Ethernet interface module
If there is a module of function version A among the modules for routing,
it is possible to access the control PLC of that particular module only. In
addition, it is possible to access other stations via a module controlled
by the same control PLC.
