how can i plot data from "read from measurement file vi"

[pvolk]

hello..

i have a problem about how to plot data that i was saved  with "write to measurement file vi"

i can see the numbers but i cannot plot them.

what's going wrong?

thank you

[Dennis_Knutson]

You should be using a waveform chart in the read program and convert the dynamic data to a scalar.

[pvolk]

thanks for the answer..

i connected convert dynamic data to scalar and seems to work

but the time not running.

can i see  time running?

i mean i want to see period of that signal,can i do with that way?

[Dennis_Knutson]

What kind of time do you expect? The file write program writes a single sample whenever you click the run button. This is completely random so the interval is not regular like a chart expects and you aren't including any time data with the simulated data so the dt is defaulting to 1 - both in the file you write to and for the chart you display the data with. According to the file, you have about 100 seconds worth of data and that is exactly what the chart is displaying.

And why do you even have the while loop in the file write program? It does absolutely nothing? What in general are you trying to accomplish with these two programs?

[pvolk]

i made a mistake ,time is running.

"readdata" can reads data which saved at .XLS

i want to store and then read a sine .

can i read RMS value from that signal?

is it possible?

i tried to did this with "amplitude and level measurements" but failed.

[Andrew_E]

Hi,

Have you tried putting the rms.vi down and wiring your signal going into your graph into the vi?

[pvolk]

hi Andrew..

i made this..

i put a table   (0,22,50,78,82,90,82,78,50,22, 0,-22,-50,-78,-82,-90,-82,-78,-50,-22)
  into .xls that "simulate" a sine .
  i call that table and calculate RMS value.                       

 on paper this table equals 62,9(rms)

labview has the same result

can you tell me your opinion?  (right,wrong)

[Andrew_E]

Hi,

Yeah, your vi does correctly calculate the rms of your table. You can do it that way that, which calculates as you are reading data or you can use the rms in post processing. I provided an example.

[pvolk]

thank  you a lot Andrew

,i ll see  your VI. it may be usefull for what i m planning to do