Hitachi SJ-P1 Series User Manual page 51

Chapter 7
[Response]
The coils in the response message are packed as
one coil per bit of the data field.
When reading 15 coils with the coil number of
0001h through 000Fh (in the above request), it
returns the codes the following.
Address Blocks
0
1
2
Modbus TCP
3
header part
4
5
6
7
8
Modbus
9
data part
10
Hi: high order
Lo: low order
The status of outputs 8 through 1 is shown as the
byte value "40h", or binary "0100 0000b". Output
8 is the MSB of this byte, and output 1 is the LSB.
Likewise, the status of outputs F through 9 is
shown as the byte value "12h", or binary "0001
0010b". Output F is in the seventh bit position
from the right, and output F is the MSB of this byte.
The one remaining high order bit is zero filled.
Bit7
0008h
Coil status 1
OFF(0)
Remain
Coil status 2
OFF(0)
↑
If the returned output quantity is not a multiple of
eight, the remaining bits in the final data byte will
be padded with zeros (toward the high order end
of the byte).
Items
Transaction ID (Hi)
Transaction ID (Lo)
Protocol ID (Hi)
Protocol ID (Lo)
Data size (Hi)
Data size (Lo)
Unit ID
Function code
Byte conut
Output status 1
Output status 2
Bit6 Bit5
0007h 0006h
ON(1) OFF(0)
000Fh 000Eh
OFF(0) OFF(0)
7-6
About the Modbus TCP
Code
15h
01h
00h
00h
00h
In the case, 5 byte lengths
(address 6 through 10).
05h
FFh
01h
02h
Coil number:
40h ←
"0008h"through"0001h"
Coil number:
12h ←
"000Fh"through"0009h"
By convention, bits within a byte are shown with
the MSB to the left, and the LSB to the right.
Bit4 Bit3
0005h 0004h
OFF(0) OFF(0)
000Dh 000Ch
ON(1) OFF(0)
Bit2 Bit1
0003h 0002h
OFF(0) OFF(0)
000Bh 000Ah
OFF(0) ON(1)
Bit0
0001h
OFF(0)
0009h
OFF(0)