Requirements for changing a value

You can only change the values of archived data points.

You must assign your data points (for the HistoryDB) to the required archives, taking into account the same considerations that apply to the HistoryDB and compression (see HistoryDB and Compression).

For predefined values, the first valid archive values are not displayed until the end of the first archival period. For instance, hourly values can only be retrieved and corrected after one hour.

The archivesused in configuration should already have been created with the correct parameters and opened prior to use.