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Verifying the Output of a DAC IC

I created this VI to test DAC IC's using some open source code from Aardvark. I'm using labview to test and qualify DAC IC's over a range of temperature, so I made this VI to test four 8 bit DAC IC's sequential order starting with Address 0xC, during this time the for loop increment's the output cmd address from 0 to 255 (Hex) so that I can test every bit of the DAC. Each bit enabled should create a 19.5mV increase until it reaches 5V. The output graph looks like stair steps (see attachment). Now that I have all that working, I would like to somehow track the errors if a bit did not increment to the next bit value. How can I do this? I would also like to add show the bit setting on the x-axis so that the graph represent the data correctly, y-axis = volts and x-axis = bit setting.

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Message 1 of 5
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Do a search for "DAC Linearity".  DACs are generally qualified by their INL and DNL values.  NI has some sample libraries available to do the analysis.

 

http://www.ni.com/white-paper/5366/en  --  Overview

http://zone.ni.com/devzone/cda/epd/p/id/4477  --  Old example code for testing Video DACs

 

That should get you started.

LabVIEW Pro Dev & Measurement Studio Pro (VS Pro) 2019
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Message 2 of 5
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Thanks for the reply. I was going to implement an INL and DNL test to my test program to compare against the data sheet. Thanks for the links!

 

On another note, the second link you suggested has a .dll file to download. Where do I save this file in order to use it.

 

 

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Message 3 of 5
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I don't see a dll that needs to be downloaded. There is a llb or LabVIEW library. This can be installed anywhere you want. Use file open to browse to the VIs inside. You can also convert it to a folder.

You should also be aware that the code is old and uses the obsolete traditional DAQ driver so you will have to convert it to use current DAQmx functions.
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Message 4 of 5
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Thnaks for the help! you're right it was a .lib file

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