In Alpana, two Query Types are possible for Wonderware Historian :
- History Values
- State Statistics
You can select the Query Type from the listbox at the top of the Query panel :
This is the classic Historian Query for showing trends.
A history of Tag values is returned.
This query (sometimes called “State Summary Values”) allows to calculate how much time a Tag had value.
This allows to calculate for example, how long an equipment was in each of its states, and calculate performance indicators.