05-19-2017 01:59 AM
I am probably being a tad dense in all of this but what is the minimum output voltage that I can set on the PXIe-4461? Just a basic sinewave at 1KHz. I am setting the attenuation to 40 so the full scale for that range is +/-100mV. I have seen (and verified) the calculations that the AO accuracy in this range is ~1.5mV. While I am at it, what is the minimum step size in this range -- I need to perform an adjust to reach on a signal. What is the minimum step size possible? The calibration procedure "only" tests the output to 90mV for acceptance, so anything less than that is, perhaps, suspect?
Thanks!
05-19-2017 08:56 AM
As this uses a delta sigma converter, you get 24-bits of resolution converting from an analog signal to digital. This means that at full scale +/- 10V (20V span) you get the following resolution: [ 20V / 2^(n-1) ] where n is the 24 bits. The result is 1.192uV resolution. This signal resolution is almost 90,000 times smaller than your sensitivity level meaning that you have about 16-bits being ignored for your check. That is a gross functional test ignoring over 65% of capability.
05-26-2017 06:12 PM