Reconfiguring Tags

There are some scenarios when a tag of some name needs to be changed. For example, a tag of name “MyIntegerTag” is 16-bit integer with some data already stored by the SDK application. Then later that tag was required to be changed to a 32-bit integer to store larger numbers. In this case, the SDK application simply needs to create another tag metadata instance of the same name, specify a different data type, and then call the HistorianAccess.AddTag() method for that tag metadata instance. The AddTag() method will return a new tag key that should be used from now on to store 32-bit integer values.

Internally, the managed HCAL will create another unique metadata instance for the same tag name with a different TagId, which will be automatically pushed to the historian’s Runtime database and will replace the previous one. Data for both tag versions will remain accessible.