Mitsubishi Electric MELSEC-L Series - Page 21

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CHAPTER 1 DATA LOGGING
1
1.1 Features
(2) Control data can be logged without missing a change.
Data logging is available every scan or on the millisecond time scale. Since changes in the specified control data
can be logged, the data logging function is effective to identify the cause of a problem. Also, logging is performed
at a high speed so that equipment can be analyzed with high accuracy.
Data logging is the best-effort type
*1
function. Logging may not be performed at a specified sampling interval because
processing time may vary depending on the configuration or the other connected devices. After configuring the system,
thoroughly examine the processing time before starting the system operation. (
Page 140, CHAPTER 10)
*1 The concept of obtaining the maximum performance from the condition at the time.
(3) Problem analysis can be speeded up. (Trigger logging function)
The states and changes in data can be stored as the data before and after a trigger. Since only the data before
and after occurrence of each problem can be stored, the cause of the problem can be identified quickly, and file
space can be saved.
When sampling data at intervals of 1ms
1ms
Slight changes in data
are caught.
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Data before trigger
Data after trigger
Trigger occurred
Range of the data stored in a file