MATLAB: How to obtain the compiled value of a block parameter in Simulink 7.9 (R2012a)

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I need to find out the compiled value of a block parameter.

For example, I need to obtain the compiled value of a block´s gain parameter (see attached model test_model).

Using the “get_param(blockname,'gain')” command, I can obtain the string which is contained in the block's dialog box (ex: 'a+b'), but not the compiled value of the parameter.

I do not know in which workspace the variables are defined and therefore in which workspace I can evaluate the expression.

For example the variables a and b could be defined in MATLAB's base workspace or in a mask.

Best Answer

You can obtain the compiled data of a block, using the block's "run time object".

This is documented in the section “Accessing Block Data During Simulation” of Simulink's documentation.

This is an example of a script that returns the compiled value of the gain:

test_model([],[],[],'compile')
rto = get_param('test_model/Subsystem/Gain','RuntimeObject');
compiledData = rto.DialogPrm(1).Data;
disp(compiledData);
test_model([],[],[],'term')

Related Solutions

MATLAB: How to determine the port data type of a masked subsystem in Simulink 7.5 (R2010a)

This can be done by querying the "CompiledPortDataTypes" block parameter after compiling the model. To see how you can do this, follow these steps:

1. Download the attached model "example.mdl".

2. Compile the model with the following command:

>> example([],[],[],'compile')

3. Query the "CompiledPortDataTypes" parameter of the subsystem block:

>> get_param('example/Subsystem','CompiledPortDataTypes')

This returns the port data types in cell arrays of strings, stored in the returned structure's "inport" and "outport" fields.

4. Terminate compilation:

>> example([],[],[],'term')

MATLAB: How to update a GUI with values from the Simulink model as it is running

There is no direct way to access the runtime parameters of a Simulink model from a MATLAB GUI. To work around this issue, you need to create a function that will update the GUI with the desired model data at each time step. An outline of this procedure is as follows.

1. Create a GUI with a control that you would like to update with information from the model. In this example, we would like to see the output of the model's Gain block in the GUIs edit text window.

2. Create a model callback function that will register an event listener for the block in question. This function will be called every time the block is updated. We will use it to access the value of the Gain blocks output and pass them to the GUI. In this case we will use the models 'StartFcn' callback.

%The GUI handles are by default hidden, turn them on
set(0,'ShowHiddenHandles','on');
%Set up the arguments that will go into the gain block event callback listener
blk = 'mytestmdl/Gain';
event = 'PostOutputs';
listener = @updategui;
%Create the listener
h = add_exec_event_listener(blk, event, listener);

3. Create a MATLAB file function that will get the Gain block's runtime output parameter and pass it to the GUI.

function varargout = updategui(varargin)
%create a run time object that can return the value of the gain block's
%output and then put the value in a string.  
rto = get_param('mytestmdl/Gain','RuntimeObject');
str = num2str(rto.OutputPort(1).Data);
%get a handle to the GUI's 'current state' window
statestxt = findobj('Tag','curState');
%update the gui
set(statestxt,'string',str);

Best Answer

Related Solutions

MATLAB: How to determine the port data type of a masked subsystem in Simulink 7.5 (R2010a)

MATLAB: How to update a GUI with values from the Simulink model as it is running

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