Load external file in ssc block Simscape

I build a "liquid valve" component (.ssc file) in Simscape which includes a dropdown menu to select different valve types. The parameters for each valve are stored as a structure in a separated .m file. Depending on which valve is selected, I would like to "load" the corresponding values into my "liquid valve" component (.ssc file). Similar to the "Thermal Liquid Properties (TL)" component which loads an external file depending on the selected fluid.

How do I "load/import" my external .m file (structure) into my simscape component?

[Yifeng Tang]

My initial thoughts are to put a mask on the Simscape component(s), and use set_params to pull the values from the data source into the mask.

Answer 1

[Shishir Reddy]

Hi moritz

As per my understanding, you would like to “load” the corresponding values into the “liquid valve” component depending upon the valve selected.

For this, the simscape component should be modified as follows

parameters
    % Define the parameters with initial values and units  
    param1={0, 'unit'}; %unit should be replaced with the actual units of param1 
    param2 = {0, 'unit'};
    % Add more parameters as needed
end

function setup
    % Loading the parameters from the external .m file
    % Ensure the .m file is on the MATLAB path
    params = feval('valveParams', valveType);
    % valveParams is the separated .m file which contains a function that returns the structure of parameters based on the valve type.
    % valveType is the type of the valve selected from the dropdown.
    
    % Assign the loaded parameters to the component parameters
    param1 = params.param1;
    param2 = params.param2;
    % Assign more parameters as needed
end

By following this method, parameters can be loaded dynamically to the simscape component based on the selected valve type.

For more information regarding the “feval” function kindly refer the following documentation https://www.mathworks.com/help/matlab/ref/feval.html

I hope this helps.

[Moritz]

Hi @Shishir Reddy

Thanks! This is, what I was looking for and it works! :)

However, I get the following warning,

Warning: File: Line: 1, the unit of value assigned to 'param1' was changed from '1' to 'Pa'.

when I use this setting.

parameters
    param1 = {0, 'Pa'}; 
end

function setup
    params = feval('valveParams', valveType);
    param1 = params.param1;
end

I can suppress the warning, by adding the 'unit' in the 'function setup',

parameters
    param1={0, 'Pa'}; 
end

function setup
    params = feval('valveParams', valveType);
    param1 = {params.param1, 'Pa'};
end

To me, this seems to be redundant. Is this correct or can I solve this differently?

Matlab states that using the setup function is not recommended ((Not recommended) Prepare component for simulation - MATLAB - MathWorks Benelux). Would it be possible to do the same things without using the setup function? I am just curious.

Thanks!