Simulink - change in behaviour of Enumerated Constant block with R2023B?

My company is running tests to make sure our old models work with the latest Simulink version. We have a test of all the default block types, and the Enumerated Constant block is giving us an error.

It's set up exactly like the default described in this page : https://www.mathworks.com/help/simulink/slref/enumeratedconstant.html

Enum SlDemoSign with default value SlDemoSign.Positive

When we run the model it gives:

Error in opInitFunction (line 101)
			GenerateModel(action, model, platform, preBuildCmd, postBuildCmd, listSub, StandAloneModel, SlxFormat, compilerVersionName); - Show complete stack trace
Caused by:
    Error using opInitFunction>CompileModel
    'Enum: SlDemoSign' does not resolve to a valid data type for parameter 'OutDataTypeStr' in 'rtdemo1_all_blocks/SS_ALL_BLOCKS/all_sources/Enumerated Constant'. - Show complete stack trace
        Error using opInitFunction>CompileModel
        Cannot register enumerated data type because value specified is not a class. - Show complete stack trace
    Error using opInitFunction>CompileModel

optoolbox.rtlabtools.rtlab_api_helper: INFO:     Error evaluating parameter 'Value' in 'rtdemo1_all_blocks/SS_ALL_BLOCKS/all_sources/Enumerated Constant' - Show complete stack trace
        Error using opInitFunction>CompileModel
        Unable to resolve the name 'SlDemoSign.Positive'. - Show complete stack trace

Running the model and clicking the Enum shows this:

Following the instructions here: https://www.mathworks.com/help/simulink/ug/using-enumerated-data-in-simulink-models.html

I was able to get it working by creating a SlDemoSign.m file. I don't know why this is necessary now, though.

classdef SlDemoSign < Simulink.IntEnumType
    enumeration
        enum1(0)
        Positive(1)
    end
    methods (Static)
        function retVal = getDefaultValue()
            retVal = SlDemoSign.enum1;
        end
    end
end

This is a new problem with Simulink R2023B. Our models are all from version R2015B which we can't change because they need to be backwards-compatible.

Does anyone have any insight? Thank you

[VIGNESH BALAJI]

@Jamie i am also using Matlab R2023B and facing the same problem. Where did you add this file ? Can you please provide me clear instructions for a beginner ?

Answer 1

[Ayush]

Hi Jamie

I understand that the “Enumerated Constant” block is erroring out by default in MATLAB R2023b which was not the case in the earlier versions.

Based on your exploration, you are on the right path in creating a “SIDemoSign.m” file in your project workspace to define the enumerations class for the block and is the expected behaviour as per the documentation. In earlier versions of MATLAB up until R2023a this file “SIDemoSign.m” was referred by the “Enumerated Constant” block by default. Please refer to the below documentation to know more about how to use enumerated data in Simulink Model:

- https://www.mathworks.com/help/simulink/ug/using-enumerated-data-in-simulink-models.html

Upon further investigation, this file/script for the class definition was used by an example present in the root workspace, hence was accessible by the “Enumerated Constant” block by default. It has now been moved to the Example Manager in MATLAB R2023b and hence it is no longer in that path and thus leading to an error.

% In R2023a
>> which SlDemoSign
C:\Program Files\MATLAB\R2023a\toolbox\simulink\simdemos\simfeatures\SlDemoSign.m  % SlDemoSign constructor

% In R2023b
>> which SlDemoSign
'SlDemoSign' not found.

Here is the reference for "SIDemoSign.m" that you can use to define an enumerations class in your model's base workspace and resolve this issue across your model.

% In R2023b you can run:
>> openExample('SlDemoSign.m')
% to open the file, which will also show where you can find it now.

Hope it helps,

Regards,

Ayush Misra

[Jamie]

Thank you Ayush, indeed I've been able to get this going by using a SlDemoSign.m from an earlier version of MATLAB.

The one I posted above is incomplete, the full file is as follows:

classdef SlDemoSign < Simulink.IntEnumType
% SLDEMOSIGN Enumerated class to represent sign of real numbers
%
%   Allowable values:
%   - SlDemoSign.Positive
%   - SlDemoSign.Zero
%   - SlDemoSign.Negative

%   Copyright 1990-2010 The MathWorks, Inc.

  enumeration
    Positive(1)
    Zero(0)
    Negative(-1)
  end

end

% EOF