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MELSEC-Q
7 PARAMETER SETTING
(5) Type specification of the target MODBUS
®
device
(a) Set the type of the read/write target MODBUS
®
device.
b15
b8 b7
b0
Read target
Write target
Set Value
Target MODBUS
R
Device Type
00
H
Not
specified
01
H
Coil
02
H
Input
04
H
Input
register
05
H
Holding
register
(b) Setting range
The following table gives the combinations of read and write targets
available for the target MODBUS
R
device type setting. Any other
combinations are not available.
Type Specification of the Target MODBUS
R
Device
Set value
Read target
Write target
Issued Function Code
0100
H
Coil
01
Read
coils
0200
H
Input
02 Read discrete inputs
0400
H
Input device
04 Read input registers
0500
H
Holding
register
Not specified (*1)
03 Read holding registers
0001
H
Coil
15 Write multiple coils
0005
H
Not specified (*1)
Holding register
16 Write multiple registers
0505
H
Holding register (*2)
Holding register
23 Read/Write multiple registers
* 1: To perform only read or write, set "0" to each of the following:
Head buffer memory address
Target MODBUS
R
device head number
Access points
* 2: Reading and writing can be performed simultaneously with one instruction only when
0505
H
(Read/write multiple registers) is set.
(6) Head buffer memory address (Read setting/Write setting)
(a) As the head buffer memory address, specify the head address of the buffer
memory that will store the data read from or written to the slave.
(b) The head buffer memory address must not be duplicated in the automatic
communication parameters 1 to 64. Set different head buffer memory
addresses to each of the automatic communication parameters.
(7) Target MODBUS
®
device head number (Read setting/Write setting)
(a) As the target MODBUS
R
device head number, specify the head number of
the read or write target MODBUS
R
device.
(b) As the target MODBUS
R
device head number, set "(last 5 digits of actual
device number) - 1".
Example: Set "17" when the head number of the holding register is 400018.
(c) When specifying a value of 32768 (8000
H
) or more in a sequence program,
set the value in hexadecimal.