Verifying the Output of a DAC IC

Question

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.
Attachments:
MWSnap352.jpg ‏179 KB
MWSnap350.jpg ‏112 KB

Answer 1

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.
Using LabVIEW: 7.1.1, 8.5.1 & 2013