Mitsubishi Electric QJ71MB91 User Manual page 122

5
FUNCTIONS
Master
(QJ71MB91)
Slave 1
5
- 7 5.2 Master Function
5.2.1 Automatic communication function
(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.
Response monitoring timer
Request
message
Request
Response
message
Message
processing
Figure 5.7 Response monitoring timer operation
If the Response monitoring timer times out, the corresponding bit in the buffer
memory's automatic communication operating status storage area turns ON.
(address: 0C20 to 0C21
H
(g) The Response monitoring timer is terminated
When the master (QJ71MB91) receives a response message, the Response
monitoring timer is terminated.
Response monitoring timer
Receiving
Request
response
message
message
Error occurred at
the station
/0C22 to 0C23 )
H H H
Response monitoring timer
times out
Because of the error, request message
cannot be processed.