MATLAB Answers

Matt Garrett

Can't pass parameters from a mask to a subsystem

Asked by Matt Garrett
on 25 Apr 2011

I've got a subsystem model with a Constant block whose constant value is "m".

I masked the subsystem and on the parameters tab I added a line with the following items:

#: 1, Prompt: multiplier, Variable: m, Type: edit, ...

In my top model I added a reference to the masked subsystem model. Within the top model I double-clicked on the masked model and entered a value for "m" on the "Model Reference (mask)" dialog.

But when I run the model, it tells me that m is undefined in the subsystem model. I tried creating a new variable called m in the Matlab workspace and re-running the model. That worked. So I can pass a parameter value from the Matlab workspace to my subsystem model but not from the subsystem mask. What am I doing wrong with the mask?

Thanks in advance for helping. Matt


Arnaud Miege
on 26 Apr 2011

It should work, so you must be doing something wrong. Could you upload your model to a filesharing site?

Thanks Arnaud, but I managed to figure it out based on Jarrod's response below.

1 Answer

Answer by Jarrod Rivituso
on 26 Apr 2011
 Accepted answer

Are you masking a Model block, or a subsystem?

It sounds like you added a mask to a subsystem in your top description. However, the "Model Reference (mask)" dialog makes it sounds like you are entering the parameter in a Model block mask.

Passing parameters into a Model Reference requires that you add the parameter to the model's Model Workspace (View -> Model Explorer) and then designate the variable as a parameter in the "Model Arguments" list. Then you can mask the Model block, and override parameters.

So, in summary

  1. Add m to the model's model workspace
  2. Write "m" in the Model Arguments option (found in the model worksapce)
  3. In the particular instance of the Model block, right-click and select Model Reference parameters, and then put "m" in the Model Arguments.
  4. Mask the Model block the way you have done.

Give that a try and let us know if you have any more problems.

Here's a link for reference:

  1 Comment

Hi Jarrod,

Thank you for your help. Yes, I was masking a Model block. To use my obviously inaccurate terminology, my "subsystem" was a pre-existing mdl file. The only way I could figure out how to include it in my higher-level model was with a model reference, but it sounds like there might be a simpler way...?

Thank you again for your detailed and accurate diagnosis.

Matt Garrett
ATA Engineering
Golden, CO, USA

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