Mitsubishi Electric Melsec Q Series User Manual page 29

1
OVERVIEW
(3) Buffering function for reliable data acquisition/transmission
(a) Even if the frequency of data transmission triggers is high, no trigger will be
[MES interface module]
[When loads are concentrated]
Job 1-1)
Trigger conditions
met
Job 1-2)
Trigger conditions
met
Job 3-3)
Trigger conditions
met
Time
[When loads are reduced]
Time
The numbers 1) to 3) show the order in which trigger conditions of respective jobs are met.
Job 1 and 3 are assumed to access the same database.
missed. (Trigger buffering function)
When multiple sets of conditions for data transmission are met in a concentrated
manner, their data and trigger times can be buffered in the module's internal
memory.
After the loads are reduced, data operations and transmission are executed using
the buffered data.
Trigger buffer
Job 1-2) Trigger information (Tag data, time)
Job 3-3) Trigger information (Tag data, time)
After loads have been reduced
Trigger buffer
Figure 1.4 Data buffering in the case of load concentration
Sending
Job 1-1)
data
Action
execution
Database
Executes action of Job 1-1), and
stores trigger information of Job 1-2)
and 3-3) in the trigger buffer.
Time
Sending
Job 1-2)
data
Action
execution
Database
Job 3-3)
Action
execution After completing the action of Job 1-1),
executes actions of Job 1-2) and 3-3)
in this order based on the trigger buffer
information.
Time
1.1 Features
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