Mitsubishi QJ71MB91, User Manual

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5
- 7 5.2 Master Function
5.2.1 Automatic communication function
5
FUNCTIONS
(f) The Response monitoring timer times out
If an error occurs at the relevant station (e.g. programmable controller CPU), the
slave may not be able to send a response message.
In such a case, the Response monitoring timer times out.
If the Response monitoring timer times out, the correstponding bit in the buffer
memory’s automatic communication operating status storage area turns ON.
(address: 0C20
H
to 0C21
H
/0C22
H
to 0C23
H
)
(g) The Response monitoring timer is terminated
When the master (QJ71MB91) receives a response message, the Response
monitoring timer is terminated.
Figure 5.7 Response monitoring timer operation
Response monitoring timer
Master
(QJ71MB91)
Slave 1
Request
message
Receiving
response
message
Request
message
Response monitoring timer
Request
message
processing
Error occurred at
the station
Response monitoring timer
times out
Because of the error, request message
cannot be processed.
Response
Message