Mitsubishi Electric QJ71MB91 User Manual page 120

5
FUNCTIONS
(QJ71MB91)
Master
Request
(QJ71MB91)
message
Slave 1
Slave 2
Slave 3
5
- 5 5.2 Master Function
5.2.1 Automatic communication function
(a) The Request interval timer times out, and then restarts
The Request interval timer represents the interval between any successive
request message transmissions in the automatic communication function.
( Section 7.2.1 (3))
Request interval timer times
out, and then restarts
Request interval timer
Master Request
message
Request
Slave message
processing
Figure 5.3 Request interval timer operation
(b) Request message is issued to the station
Request messages are issued at the timing shown in the above (a).
(c) The Response monitoring timer/Broadcast delay starts
The Response monitoring timer is used to monitor the time taken between a
response message transmission from QJ71MB91 and reception of a response
message from a slave.
The Broadcast delay monitors the time interval between transmissions when
request messages are broadcast.
The Response monitoring timer/Broadcast delay starts when a request message
is sent.( Section 7.2.1 (4))
Request interval timer
Response monitoring timer
*1
Request
Response
message
Message
processing
Figure 5.4 Response monitoring timer/Broadcast delay operation
Receiving
response
message
Response
message
Start Response monitoring
timer/Broadcast delay
Request interval timer
Broadcast delay
Receiving
*2
response Request
message
message
Request
message
processing
Request
message
processing
Request
message
processing
*1 When request message is addressed to station No.1 to 247
*2 When request message is addressed to station No.0 (Broadcast)
Request
message
Request
Response
message
message
processing
Request
message
Receiving
response
message