Mitsubishi Electric GT16, User Manual

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63 - 6
63. MODBUS(R)/RTU CONNECTION
63.5 MODBUS/RTU Equipment Side Setting

Address
GT Designer3 converts the device numbers into
decimal format according to the address map of the
MODBUS equipment to be used.
The table below shows the representations on the
MODBUS/RTU communication protocol and GT
Designer3.
POINT POINT POINT
Address conversion example
When monitoring the holding register's address
"1234H," GT Designer3 displays "4*****" since GT
Designer3 processes the internal conversion in
decimal format as follows:
GT Designer3 converts the holding register's address
"1234H" to "04660" in decimal format.
Then, "+1" is added to this decimal address since the
holding register's address on GT Designer3 always
starts from "1."
Therefore, the holding register's address "1234H" is
displayed as "404661" on GT Designer3.

MODBUS communication control function on
the GS device
(1) Functions overview
This function is to prevent the communication response
delay that occurs because the devices on the
MODBUS network differs from each other in network
specification.
This function is effective for the MODBUS network
conditions as described below:
• When only a part of function codes is supported
(Example: "0F" is not supported)
• When the maximum transfer size of function code is
small (Example: The maximum number of coil read
times is 1000)
(2) Communication setting
When the MODBUS/RTU communication driver is
assigned to multiple channel numbers using the multi-
channel function, the following cases are possible. The
communication settings are shared between the
assigned multiple channel numbers, or the individual
communication setting is configured to a specific
channel number.
By setting the device GS579, either the GS device used
for sharing communication settings (GS570 to GS576)
or the GS device used for individual communication
setting (GS590 to GS617) is validated.
(a) When sharing communication settings between
multiple channel numbers
The table below shows the settings for the GS
device.
MODBUS/RTU Communication protocol
Representation on GT
Designer3
Device name
Function code to be
used
Address
Read Write
Coil 0x01
0x05
0x0F
0000
0001
to
FFFE
FFFF
000001
000002
to
065535
065536
Input relay 0x02 -
0000
0001
to
FFFE
FFFF
100001
100002
to
165535
165536
Input register 0x04 -
0000
0001
to
FFFE
FFFF
300001
300002
to
365535
365536
Holding
register
0x03
0x06
0x10
0000
0001
to
FFFE
FFFF
400001
400002
to
465535
465536
Extension file
register
0x14 0x15
0000
0001
to
270E
270F
600000
600001
to
609998
609999
Holding register
"4 04660" +1
"404661"
1234H
GS
device
Description Set value
GS579
Validity of
setting
channel
number
Bit0: 0 Configure the Ch1 communication settings
between GS570 to GS576.
1 Configure the Ch1 communication settings
between GS590 to GS596.
Bit1: 0 Configure the Ch2 communication settings
between GS570 to GS576.
1 Configure the Ch2 communication settings
between GS590 to GS603.
Bit2: 0 Configure the Ch3 communication settings
between GS570 to GS576.
1 Configure the Ch3 communication settings
between GS604 to GS610
Bit3: 0 Configure the Ch4 communication settings
between GS570 to GS576.
1 Configure the Ch4 communication settings
between GS611 to GS617.
GS
device
Description Set value
GS570 Command selection
Bit0: 0 Using Function Code "0F"
1 Not using Function Code "0F"
Bit1: 0 Using Function Code "10"
1 Not using Function Code "10"
GS571
Function Code "01"
Specification for the
max. number of coil
read times
0:2000
1 to 2000: Specify the maximum number.
Other than above: 2000
GS572
Function Code "02"
Specification for the
max. number of input
relay read times
0:2000
1 to 2000: Specify the maximum number.
Other than above: 2000