Right-click a block or subsystem in your model and select Mask > Create Mask.
The Mask Editor appears.
Select the Parameters & Dialog pane.
Choose one or more parameters for promotion.
Click any of the icons in the Parameter palette.
Click the Promote button.
The Promoted parameter selector dialog box opens.
Choose underlying block parameters to promote to the currently selected mask parameter.
Select a parameter in the Promotable parameters table and click the right arrow button to add to the Promoted parameters list.
View the tool tips on promotable parameters to see key fields such as Type.
When masking a subsystem, you can use the Child blocks list or the Search box to find underlying block parameters to promote.
When masking a subsystem, you can associate multiple promoted parameters with the currently selected mask parameter, provided they are of the same type.
For example, you can promote multiple Gain parameters in a subsystem to a single prompt on your mask.
Click OK to return to the Mask Editor.
Edit the prompt names for the mask, if desired. You cannot edit the variable names of built-in block parameters. See Rules for Promoting Parameters.
Repeat step 3 to add mask parameters and add or edit additional promoted parameters.
If you want to promote many parameters from a built-in block, click Promote All .
The Promote All button is only available for block masks, not subsystem masks.
All the parameters appear in the Mask Editor. To remove any unwanted parameters, use the Delete Parameter button.
Click OK to finish editing the mask. Now whenever you set a mask parameter, you also set the value of the underlying promoted parameters.