Mitsubishi QJ71MB91, User Manual

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- 25 4.11 Diagnostics (FC: 08)
4.11.1 Return query data (sub-function code: 00)
4
MODBUS(R) STANDARD FUNCTIONS
4.11 Diagnostics (FC: 08)
Executes the various diagnostics and checks the QJ71MB91 status and communication
status.
4.11.1 Return query data (sub-function code: 00)
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)
(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 the buffer memory in the case of error completion.
Refer to the following for storage location, confirmation methods, and detailed contents.
Section 11.4
Figure 4.28 Return query data (Request message)
Figure 4.29 Return query data (Exception message)
(L)
Data
Function code
Function
code
(08
H
)
Sub-function code
Sub-function code
(0000
H
)
Arbitrary data
(H)
Data
Function code
Function
code
(88
H
)
Exception
code*
1