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4.11 Diagnostics (FC: 08)

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

MODBUS(R) 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:

• Ignores all request messages except for those of restart communications

option.( Section 4.11.2)

• Stops counting of the diagnostic counter.( Section 11.3)

• Continues recording with the communications event log.( Section 4.13)

(1) Request message format (Master Slave)

(2) Response message format (Slave Master)

(When completed normally)

No response message is returned because the listen only mode (offline status) is

active.

(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 4.38 Force listen only mode (Request message)

Figure 4.39 Force listen only mode (Exception message)

(L)

Data

(L)

Function code

Function

code

(08

Sub-function code

(0004

(0000

(H)

Data

Function code

Function

code

(88

Exception

code*

Mitsubishi QJ71MB91 User Manual

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