Main Content

Integrate Custom Function Block in Generated Code

To integrate a custom function block, ExternallyDefinedBlock, this procedure uses the example plcdemo_external_symbols.

  1. In a Simulink® model, add a MATLAB Function block.

  2. Double-click the MATLAB Function block.

  3. In the MATLAB® editor, minimally define inputs, outputs, and stubs. For example:

    Functions that have only one output, no states, and do not access global variables are generated as FUNCTION in the generated structured text code.

    function Y = fcn(U,V)
    % Stub behavior for simulation. This block 
    % is replaced during code generation
    Y = U + V;
  4. Change the MATLAB Function block name to ExternallyDefinedBlock.

  5. Create a subsystem from this MATLAB Function block.

  6. Complete the model to look like plcdemo_external_symbols.

  7. Open the Configuration Parameters dialog box for the model.

  8. Add ExternallyDefinedBlock to PLC Code Generation > Identifiers > Externally Defined Identifiers.

  9. The plcdemo_external_symbols model also suppresses K1 and InBus. Add these symbol names to the Externally Defined Identifiers field, separated by spaces or commas. For other settings, see the plcdemo_external_symbols model.

  10. Save and close your new model. For example, save it as plcdemo_external_symbols_mine.

  11. Generate code for the model.

  12. In the generated code, look for instances of ExternallyDefinedBlock.

    The reference of ExternallyDefinedBlock is:

    The omission of ExternallyDefinedBlock is: