Assigning Dynamic Variables in Simulink

How do I create a variable/ output a variable from a function using user defined matlab function block in simulink. The code of which is given below:

function y = fcn()
y = input('enter the variable value: ');
end

Using this code for the function gives an error in SIMULINK. I want Simlink to ask me for the value to be entered once I start the simulation.

Assume the there are only two blocks, i.e. User-defined function block and display block in simulink workspace.

[Fangjun Jiang]

This is unrealistic. Keep in mind that the MATLAB Function block is executed in every simulation step, like every 1ms. Do you want to enter the value 1000 times for 1 second of simulation? What is your real need?

[Sushanth Manchikatla]

I need to create an interface where I can fix variable(s) by chosing from a prompt given by simulink/matlab. So how do I code this prompt? And this variable is fixed for all the simulations. I dont want to put the variable as a constant and change the value by opening the workspace everytime. Instead I need a seperate code which allows me to change the value for every execution.

Answer 1

[Fangjun Jiang]

Put the code in Model Properties, Callbacks, InitFcn. It will be executed every time the simulation is run.

MyData=input()

MyData is a variable used by the Simulink model.