LabVIEW 2009 Datalogging and Supervisory Control Module Help
»View Product Info
Requires: DSC Module
In the Shared Variable Properties dialog box, select Logging to display this page.
Use this page to configure logging for a shared variable.
This page can include the following components:
- Enable Logging—Specifies whether LabVIEW logs data and events for the shared variable.
- Log Alarms & Events—Specifies whether LabVIEW logs alarm and event data for the shared variable.
- Log Data—Specifies whether LabVIEW logs data for the shared variable.
- Value Resolution—Sets the resolution, in engineering units, for logging the shared variable value in the Citadel historical database. LabVIEW writes shared variables to the Citadel historical database in compressed format with the specified resolution. The default value is 0.01.
Enter a value of 0.0 to write the exact value of the shared variable to the Citadel historical database. Logging the exact value requires more time and disk space. This option is available only for shared variables with a Data Type of Double.
- Value Deadband—Sets the deadband percentage for logging shared variables in the Citadel historical database. LabVIEW logs a new shared variable value only if the difference between the new value and the previous logged value is greater than or equal to the deadband percentage of the engineering scale range. The engineering scale range is 100 by default. The default value of Value Deadband is 1%.
Enter a value of 0 to log every value written to the shared variable. Use this option to improve the performance of an application by limiting unnecessary datalogging. This option is available only for shared variables with a Data Type of Double.
- Logging Format—Specifies the format in which LabVIEW logs strings in the Citadel historical database. This option is available only for shared variables with a Data Type of String.
Select DSC 7.1 Text or DSC 7.1 Blob for compatibility with the LabVIEW Datalogging and Supervisory Control (DSC) Module 7.1. Otherwise, select String.
- String—Logs strings in LabVIEW string format.
- DSC 7.1 Text—Logs strings in Unicode format.
- DSC 7.1 Blob—Logs strings in raw binary data format.