can't plot using user-defined function block.

I have a Matlab code to plot a graph. but when I used the same code in Simulink as a user-defined function, I am getting a lot of parellel lines instead of the desired graph in the scope block. does anyone know how to fix this?

[madhan ravi]

share your model with your user defined function

[vishnu kannan]

The above shown figure is my problem.

the matlab code in the user-defined function is " y=sin(x) ". but i get this plot instead of a sin wave. i have attached the code. this error is equivalent to the original error i am facing in my project.

i added an input in user-defined-function (u). but i am not using it. no input is needed from simulink, i only want to execute the .m file in userdefined function and display the output in the scope.

is there any way to correct this?

Answer 1

[Fangjun Jiang]

Keep in mind that this MATLAB Function block is executed at every simulation step you run. Your funciton ouputs 201 values at every step and these values are the same from step to step. That is why your scope shows 201 straight lines.

If you want to plot sin(x). One way to do it is to add a Simulink "Clock" block and connect its output to "u". Inside your function, simply specify it as y=sin(u).

[vishnu kannan]

i want to execute the matlab code inside the user-defined function and plot using scope. my original code is very complex thats why i choose the simple code y=sin(x) to demonstrate my error.

is there any other way ?

[Fangjun Jiang]

Just remember that in Simulink, there is a "time" element. Everything goes along the simulated "time" once you press the "Run" button.

For the sake of plotting sin(x) in Simulink without time, you could use XY scope.