Effect of "Simulation stop time" to transfer function

Hello everybody, Wish everyone a good day! I had a problem like this: -With a transfer fucntion of system. When I simulated with simulink, I had change "Simulation stop time" parameter. Then, I made a graph and get two different with the following parameters 1000s, 1300s. Transfer function is a FOPDT model (first-order plus deat time) and an integral stitch. So, Who can indicate to me about it? <<

Look, Graph at stop time great.

[Christiaan]

Dear Nguyen,

Could you send a file of your Simulink model? What could be the case, is that your scope parameters (double click on scope -> parameters) either have the restriction that the 'time range' (in the tab 'general') is not long enough. Also it could be that the 'Limit data points to last' are not sufficient to plot the total line. (in the tab 'history')

For more information about the scope block, click here .

Good Luck, Christiaan

Answer 1

[Sebastian Castro]

You likely have your solver's time step specified as "auto". By default, Simulink will pick 1/50 of the total simulation time... so if you double the stop time, you also double the time step.

Go to Simulation > Model Configuration Parameters (Ctrl+E), and in the Solver pane look at your step size settings. Try changing this to a hard-coded value (like 0.1) or a MATLAB variable (Ts = 0.1) and try again.

Does this make your results consistent?

- Sebastian