Simulink: Understanding Time Steps and Sampling Frequencies

[swraman]

Hi,

I have a project due that has to be done in Simulink.

I am somewhat familiar with Simulink, but some things don't make sense to me.

First off, What determines the time step between each iteration? eg. when you have a clock in the model, what determines the change in time from one iteration to the next?

I remember working with a model once, and changing something in the model changed the sampling frequency for some reason, shich makes no sense to me.

Thanks

Raman

 

[Cyrus]

You can change the step size in the settings of the menu bar along with what kind of numeric solver it uses. i.e. ode45,ode23, etc.

 

[swraman]

So if I have a input array which is to be used in the system, then I have to make sure the values in the input array are spaced the same time apart as the step size I specify in Simulink Options?

 

[swraman]

How do I add an imput variable that is not a constant?

I have an array of values that I want the system to use, but I don't know how to get it to read the array one element at a time (each iteration I want it to take in one value from the array, and as it goes on it will read down the array).

Thanks

 

[Cyrus]

So if I have a input array which is to be used in the system, then I have to make sure the values in the input array are spaced the same time apart as the step size I specify in Simulink Options?

I'm not sure, I would google that or look on the mathworks website. It may well be that simulink just interpolates points if it needs to.

 

[Cyrus]

How do I add an imput variable that is not a constant?

I have an array of values that I want the system to use, but I don't know how to get it to read the array one element at a time (each iteration I want it to take in one value from the array, and as it goes on it will read down the array).

Thanks

Again, a question for the mathworks forums.

 

[swraman]

thanks i was able to solve itl its just the "from workspace" block.