Force Listen Only Mode (Sub-Function Code: 04) - Mitsubishi Electric QJ71MB91 User Manual

4
MODBUS STANDARD FUNCTIONS

4.11.5 Force listen only mode (sub-function code: 04)

Places a slave into the offline mode.
Used when disconnecting a slave from the network.
When QJ71MB91 is set in the listen only mode, the status is as follows:
(1) Request message format (Master
(2) Response message format (Slave
4
- 31 4.11 Diagnostics (FC: 08)
4.11.5 Force listen only mode (sub-function code: 04)
• Ignores all request messages except for those of restart communications
option.( Section 4.11.2)
• Stops counting of the diagnostic counter.(
• Continues recording with the communications event log.(
Function code
Sub-function code
Function
Sub-function code
code
(0004
(08 )
H
(H)
Figure 4.38 Force listen only mode (Request message)
(When completed normally)
No response message is returned because the listen only mode (offline status) is
active.
(When completed with an error)
Function code
Data
Function
Exception
code
1
code*
(88 )
H
Figure 4.39 Force listen only mode (Exception message)
* 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
Slave)
Data
(0000
)
H
(L) (H)
Master)
Section 11.3)
Section 4.13)
)
H
(L)