Page 622 - ExtendSim User Guide
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Model Execution
Simulation setup
Continuous tab
The Continuous tab is only used for changing the time step, stepsize calculation, or simulation order for a continuous model.
Choice
End time, Start time, Runs, Global time units
Time per step (dt)
Number of steps
Stepsize calculations
Description
For the convenience of continuous modelers who want to change stepsize, these four settings from the Setup tab are repeated on the Continuous tab. Changing any of these settings on one tab will change them on the other. See their descriptions in “Setup tab” on page 595.
Represents delta time (dt), or the length of time per step. This is the default choice for determining the granularity of the simulation run. For most pur- poses use the default setting of 1, meaning that each step will be one time unit long. A value for the number of steps is automatically calculated based on the dt entered. The value is computed as: floor(((EndTime-StartTime)/ DeltaTime) + 1.5). To see this, select the Number of steps option after changing the Time per step (dt). See also “Specifying dt or the number of steps” on page 89.
Another method for determining the granularity of time for the simulation run. In most cases, this would be a number equal to the duration (length of the simulation run); the model calculates values once for each step and each step is one time unit long. A default value for delta time is automati- cally calculated based on the number of steps you enter. The value is com- puted as (EndTime-StartTime)/(NumSteps - 1). To see this, select the Time per step (dt) option after changing the Number of steps. See also “Spec- ifying dt or the number of steps” on page 89.
These are only used in continuous simulations that change the DeltaTime system variable, such as electronics models. Most models should use Autostep fast. If the blocks that you create change DeltaTime and demand more accuracy, use Autostep slow (which divides the calculated value for DeltaTime by 5). If your custom blocks change DeltaTime but you want to ignore the changes, select Only use entered steps or dt.
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