Calculated value widget displays a value calculated by a formula based on one or more signals. It differs from virtual signals because the value is only showed in the widget and is not stored in a signal (historical data is not available).
When a new calculated value widget is added, the list of signals to be used in the formula is requested. The formula can be specified in widget menu after creation.
In the widget menu it is possible to insert other signals or manage the selected ones.
For each signal the variable to use in the formula is displayed, it is also possible to select the kind of data to use for the signal. It's therefore possible to calculate values from different kind of data, for example the last value of a signal and the average of another one
After all parameters have been set the calculated value is displayed in the widget. If the corresponding setting is selected also the formula and signals used as variable are shown.