How to save streaming data to Matlab workspace

Hi,

I am trying to save real-time streaming data obtained from hardware to Matlab workspace, I use the following command: My issue is, it only saved the last set of data, but not all data.

To save all variables from the workspace in binary MAT-file, test.mat, type

save test.mat

When I tried with this

   save('test.mat','-append'); ,

it makes my program halt, so I would like to know what is the correct way to achieve this?

Thank you.

[Renato Agurto]

Hi. Do you get an error message? Do the saved variables have the same name? maybe they are constantly overwritten

[want2know]

Thank you, yes you are right that they have same name and they are constantly overwritten, i did not get error message, I still get the file saved but i noticed that it only showed the latest set of data, what should I do to avoid this? I want it to save every set at each time step

Answer 1

[Renato Agurto]

Hi, I don't have experience in real-time streaming but I would try to have a counter (t = 1:100) and save the variable(s) in a cell. For example your variables are var1, var2,... var5 and they are overwritten every second.

Here will all data be stored in a big cell myVar

 myVar{t} = {var1, var2, var3, var4, var5};

or append every new variable. Here you get 5 "big" variables: v1,v2,v3,v4 & v5

 %initialize
 v1 = [];
 v2 = [];
 v3 = [];
 v4 = [];
 v5 = [];

And at every second append the data:

 v1 = [v1, var1];
 v2 = [v2, var2];
 ...

[want2know]

Thank you, do you mind to explain further as I don't get it, sorry..I do not want to overwrite variables, for example, I have five variables in the beginning of my test, I will still have only five variables in the end of my test, but I want to save each value of all five variables from t=1 to t=100 seconds, so I will have 100 sets of five variables (presuming one set data is saved every second)

[Renato Agurto]

Hi. I tried to explain it better (see my edited answer).