# How to plot from certain range of data?

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arymas on 16 Dec 2014
Commented: Image Analyst on 20 Dec 2014
Hi everyone,
Actually I want find the stepinfo value but I have huge amount of data (many square waves of data). As far as I know stepinfo can determine if the signal in one square wave. Therefore I want to plot the data in certain range. The data (x and y) are in same folder of the workspace. What I did is below but did not work.
1.
>> x=Scope1(:,1);
>> x=[10:0.02:20];
>> y=Scope1(:,3);
>> plot(x,y)
Error using plot.
Vectors must be the same lengths.
2.
>> x=Scope1(:,1);
>> xlim=([10 20]);
>> y=Scope1(:,3);
>> plot(x,y)
Number 2 produce no error but it plots whole data (xlim is not functioning).
I also tried with fplot (function, xlim ) but it didn't work (it plot y=x).
>> x=Scope1(:,1);
>> y=Scope1(:,3);
>> fplot('y' , [10 20])
Can anybody help me how to plot?
arys
Star Strider on 16 Dec 2014
Is ‘Scope’ the output of one or more stepinfo calls? We have no idea.
arymas on 17 Dec 2014
Scope1(:,1) --> is x4 double data which from simulink to workspace. number 1 and 3 are refer to coloum 1 and 3.

Image Analyst on 16 Dec 2014
First of all, what is Scope? Is it a 2D array of square wave data where each column is one square wave?
Next, what is stepinfo? And how is it able to determine anything ? Did you write a function called stepinfo?
Then, why do you set x = a column of Scope then overwrite it with a linear vector? So of course x is a different length than y since they are not both columns of Scope anymore.
Why do you want to plot y vs. x anyway? If they're both square waves, what sense would that make?
Then, to set the axes limits you cannot do this
xlim=([10 20]);
You must do it this way:
xlim([10 20]); % No equal sign.
arymas on 17 Dec 2014
First of all, thank you very much for xlim correction. I will try. Second very sorry for lack of info provided.
Scope1(:,1) --> is x4 double data which from simulink to workspace. number 1 and 3 are refer to coloum 1 (for x) and 3 ( for y). The stepinfo is one of the matlab tools to get control system performance (settling time, overshoot, etc..).
thank you again !
Image Analyst on 20 Dec 2014
Sorry I can't help - I don't have Simulink or stepinfo.

Sudharsana Iyengar on 17 Dec 2014
Did you try the following
x=Scope1(:,1);
y=Scope1(:,3);
plot(x,y)
xlim([10 20])
More easier option would be to use
plot(Scope(:,1),Scope(:,2))
xlim([10 20])