Infinite while loop in Matlab function block

Asked by Matthieu GATINE on 5 Oct 2018

Latest activity Answered by Walter Roberson on 8 Oct 2018

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I have made this programm to implemente it in a Matlab function block in Simulink :

function Open_area1  = fcn(Moisture_Sensor_area_1_OUT,Moisture_instruction_min,Moisture_instruction_max)
Open_area1 = 0;
if (Moisture_Sensor_area_1_OUT<Moisture_instruction_min)
   while(Moisture_Sensor_area_1_OUT<Moisture_instruction_max)
       Open_area1 = 1;
   end
end
end

But the while loop make an infinite simulation time.

2 Comments

KALYAN ACHARJYA on 5 Oct 2018

That means the following condition is always true

Moisture_Sensor_area_1_OUT<Moisture_instruction_max

Do same sort of modification (update), so that it not true after some required iteration

Matthieu GATINE on 5 Oct 2018

How can I update the value of Moisture_Sensor_area_1 when the function block is in the loop ? Does the simulation is stop during the execution of the function block ?

The input signal is a sampled sinus.

Products

Simulink

Release

R2018a

2 Answers

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Answer by Walter Roberson on 8 Oct 2018

Accepted Answer

Output = double(Input >= Min & Input <= Max) ;

No loop. No if. But you do need to substitute appropriate variables.

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Answer by TAB on 8 Oct 2018

I guess, you are trying to run the loop for checking Moisture_Sensor_area_1_OUT<Moisture_instruction_min condition for every sample time.

But Simulink's Matlab Function runs in different way. It is invoked at every sample time during model execution.

At t=0, Get the 3 function inputs from previous blocks, Call fcn with inputs, collect fcn output and send to next block

At t=1, Get the 3 function inputs from previous blocks, Call fcn with inputs, collect fcn output and send to next block

At t=2, Get the 3 function inputs from previous blocks, Call fcn with inputs, collect fcn output and send to next block

...

... and so on.

Inputs to fcn remains same during the a sample time, so loop will always run into infinity.

You don't need to use while loop. You can just use if condition to set output.

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Products

Simulink

Release

R2018a

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