Diagnostics [08H] - Hitachi SJ-P1 Series User Manual

Chapter 7
7.2.9

Diagnostics [08h]

Function code 08 provides a test (only 00: Retrun
Query Data) for checking the communication
system between the server and the client.
The normal response to the Return Query Data
request is to loopback the same data. The function
code and sub-function codes are also echoed.
[Requenst]
Address Blocks
0
1
2
Modbus TCP
3
header part
4
5
6
7
8
Modbus
9
data part
10
11
[Response]
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
Sub-function (Hi)
Sub-function (Lo)
Data (Hi)
Data (Lo)
Items
Transaction ID (Hi)
Transaction ID (Lo)
Protocol ID (Hi)
Protocol ID (Lo)
Data size (Hi)
Data size (Lo)
Unit ID
Function code
Sub-function (Hi)
Sub-function (Lo)
Data (Hi)
Data (Lo)
7-11
About the Modbus TCP
Code
15h
01h
00h
00h
00h
In the case, 6 byte lengths
(address 6 through 11).
06h
FFh
08h
00h
00h
XXh
← freely-selected
XXh
Code
15h
01h
00h
00h
00h
In the case, 6 byte lengths
(address 6 through 11).
06h
FFh
08h
00h
00h
XXh
← freely-selected
XXh