Diagnostics (Command Code: 0X08); Return Query Data (Sub-Comand Code: 0X00) - Mitsubishi FX3U Series User Manual

FX Series Programmable Controllers
3U
User's Manual - MODBUS Serial Communication Edition
7.11

Diagnostics (Command Code: 0x08)

Executes the various diagnostics and checks the FX-Series MODBUS Communication ADP.

7.11.1 Return query data (sub-comand code: 0x00)

Returns the contents of the request message without change.
Used to check if the network or the target device is operating normally. (Loopback test)
1) Request message format (Master → Slave)
Function code
2) Response message format (Slave → Master)
(When completed normally)
The slave returns the request message received from the master without change.
(When completed with an error)
*1. Exception and error codes are stored in special data registers and special auxiliary relays in the case
of error completion. Refer to Chapter 6 for storage location, confirmation methods, and other detailed
contents.
Sub-function code
Sub-function code
Function
(0000 )
code
H
(08 )
H
(H)
Function code
Function
code
(88
H
7.11 Diagnostics (Command Code: 0x08)
Data
Arbitrary data
(L)
Data
Exception
code*
1
)
7 MODBUS Standard Commands
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