3.2 Function Modules
Data Logging
3-76
14. Set the sampling and trigger settings.
Set the logging name.
• Maximum name length: 32 characters
Set the data sampling rate.
Set the data sampling period.
Specify the value and unit to control whether data is sampled every scan or once in more than one scan.
To sample data every scan, specify the same value as the scan set value.
Specify whether data is to be logged synchronized or asynchronized with the scan.
Refer to the following section for guidelines on scan settings.
Scan Setting Guidelines (page 3-80)
Setting Description
High-speed scan
Samples data synchronized with the high-speed scan.
Data is sampled immediately after completing execution of the DWG.H ladder
program.
Low-speed scan
Samples data synchronized with the low-speed scan.
Data is sampled immediately after completing execution of the DWG.L ladder
program.
Setting Description Merits Demerits
Synchronous
scanning
Data is written to
the log synchro-
nized with the scan
No data is lost.
This creates an overhead on the scan and
can cause Watchdog Errors (E.001), or
cause the CPU Unit to go down.
Asynchronous
Scanning
Data is written to
the log asynchro-
nously with the
scan.
There is no over-
head on the scan.
If the scan setting is set to a fast rate or if
the idle time of the scan is low, logging can
fall behind or data can be missed if there are
too many data points to sample.
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