On the boundary conditions (fixed rate or rating), and on the characteristics of the devices (width, threshold elevation, opening ...), it is possible to define fixed values or values that change over time.

Wherever possible, to move from a fixed value to a law function of time, just click on the symbol at the right of the field to enter.

Then the events are defined in a table by setting the date and the new value at that date.

There are two interpolation methods of data between two events:

• the step mode
• the ramp mode

The mode level corresponds to a one-time operation at a given time step. The operation is effective one time step after the date of the event.

The ramp mode is a linear evolution between two events. The value calculated at each time step is an interpolation between the previous event and the next event.

It is possible to return to a fixed value not dependent on time by clicking the "Fixed value" button.