MATLAB: How to create a global variable so that all the masked subsystems can see it

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How do I create a global variable so that all my masked subsystems can see it?

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There are a couple of ways to create a global variable so that all of your masked subsystems can see it:

1. Set the value of your variable in the Model Initialization callback function of your model. This will place the variable in the base workspace. You can then access this variable throughout your model simply by entering in the variable name.

2. Create a global workspace. To do this, use the GLOBAL function in the Initialization Page of the Mask Editor. For example, if you have a variable 'x' which should be global, use the command 'global x'.

3. Use the EVALIN command. For example, if you have a variable 'k' you would like to be global in a Gain block in your masked subsystem, enter the following command into the Parameters box of the Gain block:

evalin('base','k')

The Gain block will then use the Base workspace, or MATLAB's workspace. Of course, please be sure to define 'k' in the MATLAB workspace.

Related Solutions

MATLAB: How to declare a variable in the MATLAB workspace from a MATLAB function

Simulink has access to any variable defined in the MATLAB workspace. You do not need to declare a variable 'global'. In order to define a variable in the MATLAB workspace from a function, you can declare the variables in the function using the command EVALIN. For example:

function declare_variable
......
evalin('base','k=100');
......

In this example, when the function 'declare_variable' is called, it will generate a variable 'k' in the MATLAB workspace. This variable can then be seen by the Simulink model. Please note that if, before the function 'declare_variable' is called, a variable called 'k' exists in the MATLAB workspace already, calling the function 'declare_variable' will overwrite the existing variable 'k' with the new value (100).

For more information on the EVALIN function, see the following URL:

http://www.mathworks.com/access/helpdesk/help/techdoc/ref/evalin.html?cmdname=evalin

MATLAB: Does ASSIGNIN assign a value in the MATLAB base workspace rather than mask workspace when setting a value within the mask initialization callback in Simulink 7.0 (R2007b)

Documentation on how ASSIGNIN works with Simulink's mask workspace is missing from the product manual.

ASSIGNIN is a builtin MATLAB function that has been designed to work with MATLAB workspaces. The mask workspace is not a MATLAB workspace. Hence, when the mask initialization function calls ASSIGNIN, the variable is assigned to the MATLAB base workspace.

In order to read or write mask workspace variables, use SET_PARAM or GET_PARAM with the 'MaskWSVariables' parameter.

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Related Solutions

MATLAB: How to declare a variable in the MATLAB workspace from a MATLAB function

MATLAB: Does ASSIGNIN assign a value in the MATLAB base workspace rather than mask workspace when setting a value within the mask initialization callback in Simulink 7.0 (R2007b)

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