Mitsubishi Electric MELSEC iQ-R Series User Manual page 39

Immediately after switching the programmable controller system ON, if a trigger occurs before sampling the
number of lines of data before the trigger, the lines of the data before the trigger will be fewer than the
specified number of lines.
Continuous trigger occurrence leads to the following operations.
• After a trigger occurs, if the next trigger occurs before sampling the specified number of lines after a trigger
occurrence, the next trigger will not be detected (the trigger occurrence is ignored).
The number of times that the trigger is ignored can be checked by the trigger reoccurrence count, 'data
logging information 1 to 64' (Un\G2030 to 2989) in the buffer memory.
(Example) When sampling interval: 10 ms, Number of lines after a trigger occurs: 100 lines
Any trigger that occurs within 1000 ms after the first trigger will not be processed.
• After the first trigger occurs, triggers which occur after the number of lines worth of data is sampled, are
detected. However, if the number of lines of data before the second trigger overlaps with the number of lines
of data after the first trigger, the time data output by the first trigger will not be output in the second trigger.
Therefore, the number of lines of data before the second trigger may be shortened.
(Example) Sampling interval: 10 ms, Period when a trigger occurs: 1500 ms, Number of lines before a trigger
occurs: 100 lines, Number of lines after a trigger occurs: 100 lines
Trigger
condition
Before trigger: 100
lines
1st trigger
2nd trigger
• Between a trigger occurrence and output to a file, only one other trigger is processed. While two triggers are
being processed to be output to a file, trigger detection is not performed. Thus, if any other trigger (third or
later trigger counting from the first trigger) occurs, the trigger is not detected. During this period, subsequent
processing is not catching up with the data sampling speed, and the processing gets overloaded. To check
the processing overload count, refer to the trigger recurrence count of the 'data logging information 1 to 64'
(Un\G2030 to 2989) in the buffer memory. Check whether the data is being output to a file based on the
'data logging execution information' (Un\G2008 to 2011) in the buffer memory.
For the approximate time required for the data to be output to a file, refer to the following:
(Page 344 Processing Time)
Trigger
condition
Trigger execution
1st trigger
2nd trigger
4th trigger
1500ms
Trigger execution
After trigger: 100 lines
Before trigger: 50 lines
Trigger is not detected.
Trigger execution Trigger execution
File output processing File output processing File output processing
File output processing File output processing File output processing
Trigger execution
After trigger: 100 lines
Trigger execution
File output processing
1 FUNCTION
1.1 Data Logging Function
1
37