System Object Global Variables in MATLAB

For System objects that are used only in MATLAB, you define global variables in the System object™ class definition files in the same way that you define global variables in other MATLAB code (see Global Variables).

System Object Global Variables in Simulink

For System objects that are used in the MATLAB System block in Simulink, you also define global variables as you do in MATLAB. However, to use global variables in Simulink, if you have declared global variables in methods called by stepImpl, updateImpl, or outputImpl, you must declare global variables in the stepImpl, updateImpl, or outputImpl method, respectively.

You set up and use global variables for the MATLAB System block in the same way as you do for the MATLAB Function block (see Data Stores and Access Data Store Data in MATLAB Function Blocks). Like the MATLAB Function block, you must also use variable name matching with a Data Store Memory block to use global variables in Simulink.

For example, this class definition file defines a System object that increments the first row of a matrix by 1 at each time step. If the file is P-coded, you must include getGlobalNamesImpl.

classdef GlobalSysObjMatrix < matlab.System 
   methods (Access = protected)  
      function y = stepImpl(obj)
         global B;
         B(1,:) = B(1,:)+1;
         y = B;
      end

      % Include getGlobalNamesImpl only if the class file is P-coded.
      function globalNames = getGlobalNamesImpl(~)
         globalNames = {'B'};
      end    
   end
end