0X08) Diagnostics - Hitachi HX-RIO3 Series User Manual

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Response
Field name
Function Code
Register Address Hi
Register Address Lo
Register Value Hi
Register Value Lo
Function Code
In case of address 0x0800 output register value: 0x0000 changes to 0x1122.

7.1.7 8 (0x08) Diagnostics

Modbus function code 08 provides a series of tests for checking the communication system between a client
(Master) device and a server (Slave), or for checking various internal error conditions within a server. The
function uses a two–byte sub-function code field in the query to define the type of test to be performed. The
server echoes both the function code and sub-function code in a normal response. Some of the diagnostics
cause data to be returned from the remote device in the data field of a normal response
Request
Field name
Function Code
Sub-Function Hi
Sub-Function Lo
Data Hi
Data Lo
Response
Field name
Function Code
Sub-Function Hi
Sub-Function Lo
Data Hi
Data Lo
Example
0x06
0x08
0x00
0x11
0x22
0x06
Example
0x08
0x00
0x00
0x11
0x22
Example
0x08
0x00
0x00
0x11
0x22
HX-RIO3 Series