Use the fields within the Background Logging section of a string point’s ODBC tab to specify whether ClearSCADA is to regularly update the string’s value in the ClearSCADA database, regardless of whether that value has changed.
- Enabled—Clear this check box if ClearSCADA is only to update the string’s value in the ClearSCADA database whenever that value changes. The other fields in the Background Logging section are ‘grayed out’ and unavailable for use.
Select the Enabled check box if ClearSCADA is to regularly update the string’s value, regardless of whether that value has changed. This provides confidence that ClearSCADA is continuing to retrieve the string’s data from the other application’s database. When this check box is selected, users can monitor the string’s Last Updated status attribute to ascertain when ClearSCADA last updated the point’s value. Use the rest of the fields within the Background Logging section to specify how often ClearSCADA updates the point’s data when that value is not changing. (With a string point for which the value is changing, ClearSCADA scans the other application’s database and updates the string’s value in the ClearSCADA database at the Scan Rate specified on the ODBC Query Form (see Configure the Query Properties).)
- Interval—Use to specify the frequency with which ClearSCADA updates the point’s value, regardless of whether that value has changed.
Enter the required Interval in the OPC Time Format, for example 15M for ClearSCADA to update the point’s value at 15-minute intervals.
- Offset—Use to specify the Background Logging start time—the amount of time that occurs before ClearSCADA first updates the point’s value, regardless of whether that value has changed. You need to define the time value and time unit from which the start time is to be offset from the present time. Specify the Offset in the OPC Relative Time Format. For example, specify H for ClearSCADA to start updating the point’s value at the start of the present hour, and thereafter at the intervals specified in the Interval field, above.
NOTE: Background Logging is used to apply additional functionality to ODBC analog and digital points—see Configure the Background Logging Properties of Analog and Digital Points.