Mitsubishi Electric QJ71MB91 User Manual page 135

5
FUNCTIONS
(d) Specifying the CPU response monitoring timer
Master
Slave
(QJ71MB91)
Error occurred at
the station
(2) Setting the MODBUS device assignment parameters
Set the MODBUS device assignment parameters by the utility package (GX
Configurator-MB).(
Setting from a sequence program is also available.(
Specify the timer value so that the QJ71MB91 will monitor the processing of the
access target programmable controller CPU.(
In the case of an error at the access target programmable controller CPU and if
any response message cannot be sent, another response message (error
complete) can be sent after a given length of time has elapsed.
This will prevent the master from waiting for a response message that will not be
received.
Request
message
Because of the error, request
message cannot be processed.
CPU response
monitoring timer
times out
Figure 5.15 CPU response monitoring timer operation
Section 8.4.2)
Section 7.3.6)
Response
message (error
completed)
Response
message (error
completed)
If CPU response monitoring
timer times out, response
message (error completion) is
transmitted
5.3 Slave Function
5.3.2 MODBUS device assignment function
Section 9.1.2)
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