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What is speed of Data Acquisition with Data Acquisition Board

Hi All
I have a simple question. Yesterday i was trying to get some data from data acquisition board and i was able to acquire data at a frequency of 1 MHz. But when i tried to do the same thing using a while loop, that is i placed the DAQ assistant in a while loop by stoping it for a specified time and tried to obtaine the data with 1MHz, i could not. I could achieve the maximum rate of 1 KHz (by using wait for no of milliseconds) and that too not precise. Does that mean DAQ board has excess to some 1MHZ clock and not the while loop. Kindly answer it. Thanks in advance.
Regards
Chauhan
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Hasn't this question been discussed before in a different thread?

Of course the DAQ board has access to a different clock. It uses a clock that is on the board to determine the sample rate. A while loop and a DAQ Assistant set for sample on demand is at the mercy of the OS and the limitation of the pc's clock. The OS is always doing things in the background that requires x amount of processing time. The DAQ board clock is not subject to these interuptions. You can play games with the priority of the VI but the timing will never be as accurate or as fast as the DAQ board using it's own timing source.

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You might want to look at the tutorials at

 http://zone.ni.com/devzone/cda/tut/p/id/3216  

 http://zone.ni.com/devzone/cda/tut/p/id/3536 

and the LabVIEW Measurements Manual that ships with LabVEIW

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Thanks for this information Dennis. Regards
Chauhan


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