Read/Write Multiple Registers [17H] - Hitachi SJ-P1 Series User Manual

Chapter 7
7.2.12

Read/Write multiple registers [17h]

This function code performs a combination of one
read operation and one write operation. The write
operation is performed before the read.
[Request]
The request specifies the starting address and
number of holding registers to be read as well as
the starting address, number of holding registers,
and the data to be written.
(Example)
Configure the register number "2B02h (FA-10:
acceleration time monitor)" to 10.00[s].
Then, read the register number "2B04h (FA-12:
deceleration time monitor)".
Address Blocks
0
1
2
3 Modbus TCP
header part
4
5
6
7
8
9
10
11
12
13
Modbus
14 data part
15
16
17
18
19
20
Hi: high order
Lo: low order
*1) Configure the number of bytes to actually
change, not the number of hold registers.
Items
Transaction ID (Hi)
Transaction ID (Lo)
Protocol ID (Hi)
Protocol ID (Lo)
Data size (Hi)
Data size (Lo)
Unit ID
Function code
Read starting address (Hi)
Read starting address (Lo)
Quantity to read (Hi)
Quantity to read (Lo)
Write starting address (Hi)
Write starting address (Lo)
Quantity to write (Hi)
Quantity to write (Lo)
Byte count *1)
Write register value 1 (Hi)
Write register value 1 (Lo)
Write register value 2 (Hi)
Write register value 2 (Lo)
7-15
About the Modbus TCP
Code
15h
01h
00h
00h
00h
In the case, 15 byte lengths
(address 6 through 20).
0Fh
FFh
17h
2Bh In the case, "2B03h"
03h ("2B04h" minus 1).
00h
02h
2Bh In the case, "2B01h"
01h ("2B02h" minus 1).
00h
02h
04h
00h
00h
0000 03E8h
03h →1000d→10.00[s]
E8h