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MELSEC-Q
7 PARAMETER SETTING
(8) Access points (Read setting/Write setting)
(a) Set the number of points to be written to the MODBUS
R
device and the
number of points to be read from the MODBUS
R
device.
(b) The access points change depending on the type specification of the target
MODBUS
R
device.
Type Specification of the Target MODBUS
R
Device Access Points Setting Range
Set value Read target Write target Points to be read Points to be written
0100H Coil 1 to 2000 points
0200H Input 1 to 2000 points
0400H Input register 1 to 125 points
0500H Holding register
Not specified
1 to 125 points
0001H Coil
1 to 1968 points
0005H
Not specified
Holding register
1 to 123 points
0505H Holding register Holding register 1 to 125 points 1 to 121 points
POINT
In the access to the bit device (coil/input) of the slave, the fraction bits are handled as
described below.
1) Bit device read
Automatic communication parameter: Read setting
Type specification of the
target MODBUS
R
device
Head buffer memory
address
Target MODBUS
R
device
head number
Access points
0200H (Input) 1000H 16628 35
b0b0to tobF bF
1000H
1001H
1002H
116640 to 116625
116656 to 116641
116672 to 116657
116629
116663
<QJ71MT91 buffer memory> <Target slave device area>
Read
Remaining area is
masked with 0.
2) Bit device write
Automatic communication parameter: Write setting
Type specification of the
target MODBUS
R
device
Head buffer memory
address
Target MODBUS
R
device
head number
Access points
0001H (Coil) 3000H 1305 5
b0tobF b0tobF
001312 to 00129
<QJ71MT91 buffer memory> <Target slave device area>
Write
Remaining area is
ignored.
3000
H
001306
001310
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