A masked block is a custom interface to underlying blocks that are governed by block parameters. Mask parameters are the links to underlying block parameters.
Mask parameters are defined in the mask workspace, while block parameters are defined in the model or base workspace.
You can provide access to one or more underlying block parameters by defining the corresponding number of mask parameters. Mask parameters appear in the Mask Parameters dialog box as fields that can be edited. Simulink® applies the value of a mask parameter to the value of the corresponding block parameter during simulation.
This dialog contains fields for mask parameters Slope and Intercept, both defined in the Mask Editor.
Slope corresponds to mask workspace variable m, and Intercept, to mask workspace variable b. Moreover, names m and b correspond to the Gain and Constant value parameters of the underlying blocks.
In the mask dialog box, when you set Slope and Intercept to 5 and 2, respectively, Simulink assigns these values to m and b.
Before simulation begins, Simulink searches the workspace hierarchy, looking in the mask workspace first, for values to resolve the Gain parameter m and Constant value parameter b. Since variables m and b are defined in the mask workspace, Simulink applies their values to the block parameters.