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DAQcard-700 data vs time

Hello,
 

I'm using DAQcard 700 to receive sampled analog data to the computer. I'm planning to work with external trigger (EXTCONV) and my question is how can I receive 2 vectors of the data, one for the converted from analog to digital data itself and another for the time. In other words when trigger acquire I want to scan one sample of analog data, the time when it acquired and wait for another trigger. Is there any possibility to receive the data and the time when the data was sampled from this card?

Thank you in advance.
Regards,
 
Alex
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Hi Alex,

what Software are you using for programming this application?

Stefan

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Hi StefanK,

I'm using Windows XP and Labview 7.1.

Thank you.

Regards,

Alex

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Sounds good - have ever though about updating your hardware and program you application using the NI-DAQmx driver? Smiley Wink

Generally, it's possible to program this with your DAQCard-700 under Traditional NI-DAQ driver. Depending on your system performance, single point I/O operations should be possible up to 1kHz (check the task manager, your cpu you be quite busy ;-). NI-DAQmx has better single- point I/O performance.
In the LabVIEW example finder you can find some VI's that are a good point for getting started with DAQ- Programming - regarding your request I'd like to recommend the "Acquire 1 point digital trig.vi" - I have attached a modified version of this VI.
Since you just can read multiple datapoint when you need a dig. trigger, you need to extract the first point out of the datavalue array.

Hope this helps!

Good luck, Stefan

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Impossible is nothing - nothing is impossible
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Hello StefanK,
 
Thank you very much.
Regards,
 
Alex
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Hi,

I have another question about this card. In the user manual we can find explanation about 512 FIFO buffer to store the data from the A/D converter. Can I store the data from 2 analog channels simultaniously and is this buffer exists for every channel or is it one for all channels ?

 

Thank you in advance.

Regards,

Alex

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Alex,
 
The FIFO buffer does apply to all the channels.  Therefore, you must take the 512 samples and divide that amongst your channels.
 
-Jeff P.
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Thank you Jeffrey,

But can I receive data from 2 analog channels in the same time ? in other words how can I save data that comes from 2 analog inputs simultaneously.

Regards,

Alex

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Alex,
 
I apologize, I must have misunderstood the question.  Yes, you can recieve data from 1 up to ALL of your analog channels at the same time.  The data will be returned in LabVIEW in a 2D array that where each row represents its own channel.  Therefore, if you return 2 channels of 500 points each, you will have a 2x500 array.  You can then parse this data apart, write it to file, or do pretty much anything you want with it.  Logically, the way you do this is when you specify the channel you want to read.  Instead of specifying "Dev1/ai0", you would say "Dev1/ai0:1".  I am attaching a .JPG of the front panel and block diagram that specifies this and shows you the parameters that you will want to use.  The .JPG comes from the "Acq&Graph Voltage-Int Clk.VI" in the Example Finder.
Hope this helps!!
-Jeff P
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Thank you Jeffrey,
We finaly succeded to sample 2 channels, but we are working on Labview 7.1 and we do not have such operators that was on the image you have sent us, so we have alternated something else 🙂
 
Regards,
Alex
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