90
12
Interface
90
In
te
rf
ac
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Chapter
12
e.g.) Contents from HI limit (address 40001) to LO limit (address 40002) are read.
Note that the relative address is 0x00 when reading the HI limit value.
The F325 setting for this example is as follows.
04 (0x04) Read Input Registers
The contents of slave input registers are read.
Broadcast cannot be specified.
The start address of the input register and the number of registers are specified.
Slave devices transmit data by converting the contents of each register to 2 bytes.
*: N = Number of registers
e.g.) Contents of linked indicated value (address 30003) are read.
Note that the relative address is 0x02 when reading the linked indicated value.
The indicated value of the F325 for this example is as follows.
[Request]
Function
03
[Response]
Function
03
Start address (HI)
00
Data bytes
04
Start address (LO)
00
HI limit (HI)
00
Number of registers (HI)
00
HI limit (LO)
64
Number of registers (LO)
02
LO limit (HI)
00
LO limit (LO)
32
HI limit
100 (0x0064)
LO limit
50 (0x0032)
[Request]
Function
1 byte
0x04
Start address
2 bytes
0x0000 to 0xFFFF
Number of registers
2 byte
1 to 125 (0x7D)
[Response]
Function
1 byte
0x04
Data bytes
1 byte
2×N *
Register value
N x 2 bytes
[Error response]
Error code
1 byte
0x84 (fu0x80)
Exception code
1 byte
01 or 02 or 03
[Request]
Function
04
[Response]
Function
04
Start address (HI)
00
Data bytes
02
Start address (LO)
02
Linked indicated value
(HI)
03
Number of registers
(HI)
00
Linked indicated value
(LO)
E8
Number of registers
(LO)
01
Linked indicated value: 1000 (0x03E8)
