How to set and get value for a Data Store Memory.

Hello,

I would like to Read and Write in a Data Store Memory (DSM) with a Matlab function.

This matlab functions looks like :

1. SetValue(GlobalVarName, NewValue)
2. CurrentValue = GetValue(GlobalVarName)

The GlobalVarName shall be a string with the name of the DSM.

Currently, I have already created all my Simulink.Signal with the script, here an example:

1. % Signal Vaux
2. Vaux = Simulink.Signal;
3. Vaux.Dimensions = 1;
4. Vaux.Complexity = 'real';
5. Vaux.DataType = 'double';
6. Vaux.Description = '[Signal Vaux]; [Value = 0 to 20]; [Units = V]; ';
7. Vaux.InitialValue = num2str(12);

In my Simulink Model, I use the block DSM Write in order to change the value Vaux.

I use a slider to change the value of a constant who are connected to my Vaux DSM.

But, now I would like to read a text file, with a set of value of Vaux, instead to use the slider.

I need to use the string name of the DSM to change its value because I have hundreds of values.

Can you help me?

Thanks.

[Patrick]

Here you are an example of what I would like to perform

1. Run CreateSimSig.m
2. Run TestDSM_RW.slx

Then take a look in the Matlab function, it's what I would like to perform...

Here the code:

function updateAndReadDSMValues(file_path)

% Load data from the Excel file

data = xlsread(file_path);

% Get the list of DSMs in the Simulink model

dsm_list = find_system(gcs, 'SearchDepth', 1, 'BlockType', 'DataStoreMemory');

% Iterate through each row in the Excel file

for i = 1:size(data, 1)

% Get the variable name and its value from the Excel file

variable_name = data(i, 2);

variable_value = data(i, 3);

% Check if the variable name corresponds to a DSM in the model

if ismember(variable_name, dsm_list)

% Update the value of the DSM with the new value

set_param(variable_name, 'Value', num2str(variable_value));

disp(['The value of DSM "', variable_name, '" has been updated to ', num2str(variable_value)]);

% Introduce a delay of 50 ms

pause(0.05);

% Read the value of the variable in column 4

variable_to_read = data(i, 4);

read_value = evalin('base', variable_to_read);

% Write the read value to column 6

data(i, 6) = read_value;

else

disp(['No DSM corresponding to the variable name "', variable_name, '" found in the model.']);

end

end

% Save the updated data back to the Excel file

xlswrite(file_path, data);

end

Answer 1

[Fangjun Jiang]

See if this helps.

https://www.mathworks.com/help/simulink/ug/using-global-data-with-the-matlab-function-block.html

[Patrick]

Thanks for your answer but this link explain how to use DSM but there is no explanation about to set or get value.

I just realized that DSM or Simulink .Signal are like communication media but have no value.

It is therefore necessary to act on the parameters or on the displays.

Here's what I do:

function SetValue()

coder.extrinsic('set_param');

coder.extrinsic('getsimulinkBlockHandle');

path ='MyModel/C_Vaux'; % Where C_Vaux is the block parameter Constant connected to my DSM G_Vaux

h = getSimulinkBlockHandle(path,true);

set_param(h,'Value','13.5'); % Where Value is the value I want to set, 13.5 is the value I want to set

end

Same approach for GetValue

function GetValue()

coder.extrinsic('get_param');

coder.extrinsic('getsimulinkBlockHandle');

path ='MyModel/C_Vaux'; % Where C_Vaux is the block parameter Constant connected to my DSM G_Vaux

h = getSimulinkBlockHandle(path,true);

disp (get_param(h,'Value'); % Where Value is the value I want to get

end

So it works, I can set/get value of my Simulink model from a text file during the simulation in order to test my use case.

[Fangjun Jiang]

Simulink parameter and signal are two different things. It was not clear what was your modeling needs. The question goes directly to how to access DSM. To get/set the value of the Constant block, you can use a variable name and set its value in the base workspace. It is absolutely not necessary to use a MATLAB function or get_param() and set_param(). The DSM is probably not needed either.