A data logger samples the values of one or more variables at user-defined intervals or at every value change and stores them in a database.
TIP: You can disable automatic sampling by setting the
Sampling modeproperty to
Databases are automatically configured for data loggers.
When you select a database for a data logger, a database table with the following columns is automatically created for each variable to sample:
The value of a specific variable
The variable code of the reading operation on the controller
Log operation code of the variable = True
The date and time (UTC) of the variable reading on the controller
Log timestamp of the variable = True
The date and time of the sample reading on the controller.
This timestamp refers to the time when
FactoryTalk Optix Studiostops reading all sample variables.
The date and time of the variable reading on the controller in the machine local time zone.
Local time log = True
Automatic sample modes
A data logger can automatically sample:
- All monitored variables
- The data logger samples all monitored variables regardless of their values.
- Only the variables with significantly changed values
- Change in valuesampling mode applies only to the variables with significantly changed values.The data logger samples only the variables which values vary beyond a deadband interval in comparison with the previous sampling. The deadband interval value can be an absolute or percentage value.For example, if the deadband interval is set to5, the data logger samples only the variables that have an absolute or percentage variation of at least ±5 in comparison with the previous sampling.
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