signal integration

[shadyman]

Hi all

I'm connecting my USB 6009 data acquisition board to an instrument that generates 0 to 1 volts signal ,the signal from the device is "sampled" every 1 minute ,that means that every one minute i should be logging the data from the device to draw a wavefrom chart containing xy data ploted versus time in seconds (from 0 to 60 sec)

the problem is that ,in every cycle ,i want to integrate the signal during certain times in the cycle (ex :from 00:03 to 00:06 ,and from  00:25 to 00:28) and also those times will be fixed ,and save the integration results then reset the values and write the values of the next cycle then saves them ,and so on ....the integration result will ofcourse differ from cycle to cycle because the signal will be different too !

I'm an electrical engineer and i'm new to labview but i managed to find the numerical integration vi and wire it to the daq assistant output ,it integrates continously and i can't trigger it to integrate in the way that i mentioned previously.

I will be thankful if somebody told me what approach should i take to do this .

Regards

note: attached is an example of the signal shape that i mean with the shaded gery part that i want to integrate.

Thanks in advance

Shady

[johnsold]

Shady,

I think you have smoe terminology mixed up.  You say the signal is "sampled" every minute and then say you get data second by second.  Sampling refers to the instant at which the analog signals is digitized. One sample = 1 numerical value.  A waveform with a duration of 1 minute which contains 60 numerical values of the signal was sampled at 1 sample per second and "read" once per minute.  There is probbaly nothing wrong with the way you are acquiring the signal, but you will confuse a lot of people if you do not learn the correct terminology. Also. "logging" usually refers to saving to a file rather than just displaying on a graph.

To integrate just small segments of the data you need to extract those segments.  You can use the Get Waveform Subset Vi from the Waveform palette or extract the Y array and use Array functions to get the the segments.

Please post what you have tried so far to get suggestions on improvements.

Lynn

[shadyman]

Lynn

First of all thanks for your reply ,and yes I've got some terminology mixed up ! 🙂 sorry for that .

I get one waveform for a complete minute ,and that's what I meant when I said sampled and this is wrong I know .

Any way that doesn't have anything to do with the sampling rate ,and also this minute can contain 60 or more samples depending on the scan rate which I will use and this will be probably more than 1 S/s . and the segments of the wave can between (00:03.33)  and (00:30.12) also if i used a faster sampling rate.

I will try to use one of the ways you suggested and I will let you know what I did .

Thanks a lot !!

Regards,

Shady