Read Holding Registers [03H] - Hitachi SJ-P1 Series User Manual

Chapter 7
7.2.6

Read holding registers [03h]

This function code is used to read the contents of
a contiguous block of holding registers.
[Request]
The request specifies the starting register address
and the number of registers. In the registers are
addressed starting at zero.
(Example)
Reading information about trips ("03E9h" through
"03EDh") from the inverter.
Address Blocks
0
1
2
Modbus TCP
3
header part
4
5
6
7
8
Modbus
9
data part
10
11
Hi: high order
Lo: low order
Items
Transaction ID (Hi)
Transaction ID (Lo)
Protocol ID (Hi)
Protocol ID (Lo)
Data size (Hi)
Data size (Lo)
Unit ID
Function code
Starting adderess (Hi)
Starting adderess (Lo)
Number of registers (Hi)
Number of registers (Lo)
7-7
About the Modbus TCP
Code
15h
01h
00h
00h
00h In the case, 6 byte lengths
06h (address 6 through 11).
FFh
03h
03h
In the case, "03E8h"
("03E9h" minus 1).
E8h
00h
In the case, the number of
registers is 5.
05h