Modulation Function

In transient models, all boundary conditions can be modified by applying a time series as a modulation function. The corresponding parameter Modulation Function is added to the tree in the Data panel by using the context menu of the corresponding boundary condition.

The values of the time series used for the modulation function are multiplied with the values of the boundary condition at each time step of the simulation. This can mainly serve for two purposes:

Turning the boundary condition on and off by using gaps in the modulation function (see Time Series dialog and *.pow file format for details on the definition of gaps)
Modifying the value of a boundary condition by multiplication, e.g., for calibration purposes, seasonal distribution, distribution of a total value onto a number of nodes, etc.

Modulation functions can be easily used to turn BCs on and off, and only one modulation function may turn on and off a large number of BCs with different values or different time series attached. As a multiplication with a 'NAN' (not a number) value used for gaps in time series also results in 'NAN', a gap in a modulation function leads to a deactivation of the BC within the corresponding time interval, just as a gap in the original time series applied to the BC would

The modulation function is indicated by an icon depicting a rectangular function, both in the Data panel and on each node with a modulated boundary condition in the different view windows.