Question

I am running a simulink simulation using the fixed-step discrete solver. I’ve even specified the fixed-step size. I save some data via a “To Workspace” block (I’ve used the Scope to save to workspace as well with equivalent results). When I look at the time data in the object, the time is not monotonically increasing.

The time value is constant for 5-10 samples, then continues. Any ideas why this happens?

I took a screen shot of the Time vector. You can see it goes flat, then continues, then is flat. I expected a single line.

I asked on the Mathworks site as well. I’ll update both if I get an answer.

EDIT: I am working with Mathworks now too. They did show me how to visually inspect sample times. Navigate to Format > Sample Time Display > All. This will show all of the sample times in the simulation.

Answer 1

This problem was caused, at least partly by the existence of algebraic loops. Since Simulink was recalculating the algebraic loops, the output was capturing these changes.

I was able to click the “minimize algebraic loop occurrences” in the

Configurate Parameters > Model Referencing 

and my loops were eliminated. This is a YMMV answer, but its the best I’ve found working with Mathworks support.