Mitsubishi Electric QJ71MB91 User Manual page 167

7
PARAMETER SETTING
(4) Response monitoring timer value/Broadcast delay value
(a) Response monitoring timer value (Target station No. is 1 to 247)
POINT
The Response monitoring timer is used to monitor the time from when the
QJ71MB91 sends a response message until it receives a response message from
the slave.
If the QJ71MB91 does not receive any response message from the slave before
the Response monitoring timer times out, it is recognized that the target slave is
faulty.
*1
Master
Request
(QJ71MB91)
message
Request
Slave 1 message
processing
*1 When request message is addressed to any
of station No.1 to 247
Figure 7.3 Response monitoring timer
The following areas can be checked to see if the Response monitoring timer has
timed out.
1) Relevant automatic communication operation status storage area in the buffer
memory (address: 0C20
2) An error code is stored in the automatic communication error code storage
area in the buffer memory (address: 0C28
( Section 11.4.1)
1. The Response monitoring timer value should be smaller than the Request
interval timer value.
If the Response monitoring timer value is larger than the Request interval
timer value, a request interval timer timeout error (error code: 737B
occur.
Set an adequate response monitoring timer value, taking the processing time
of the target slave device into account.
2. While the Response monitoring timer is on, request messages cannot be sent
with the MBRW or MBREQ instruction.
When the automatic communication function and the MBRW or MBREQ
instruction are used on the same channel, set appropriate automatic
communication parameters and create a proper sequence program so that
the MBRW or MBREQ instruction can be executed in the right timing.(
Section 9.2.3)
7.2.1 Automatic communication parameter details
Response
Receiving
response
message
Response
Message
to 0C21 /0C22 to 0C23
H H H
to 0C47
H
7.2 Automatic Communication Parameter
) turns ON.
H
/0C48 to 0C67 ).
H H H
) will
H
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