In ClearSCADA, the default date and time value for items that have not yet had their date and time value set is 1-Jan-1601 00:00:00. For example, a new database point that has not had its date and time set will have a date and time value of 1-Jan-1601 00:00:00.
Some ODBC clients do not support dates as far back as 1-Jan-1601 00:00:00. For example, SQL Server 2005 does not support time stamps as far back as 1-Jan-1601 00:00:00, and so it experiences problems if the ClearSCADA contains items with the default date and time setting. By using the Return 1-Jan-1601 as NULL check box, you can avoid such problems—you can set ClearSCADA to report 1-Jan-1601 00:00:00 as null. The null value can be recognized by those ODBC clients that do not support the default 1-Jan-1601 00:00:00 date and time value.
To define whether ClearSCADA reports 1-Jan-1601 00:00:00 as null, you need to display the ODBC Setup window Configure the ODBC DSN Settings, then use the Return 1-Jan-1601 as NULL check box:
- Select the Return 1-Jan-1601 as NULL check box to configure ClearSCADA to return a null value for any time that has yet to be set. For example, if there is a new database point that has not had its time set, it will have a null value instead of the default 1-Jan-1601 00:00:00 value.
- Clear the Return 1-Jan-1601 as NULL check box if you are certain that your ODBC client supports 1-Jan-1601 00:00:00.