From Friday, April 19th (11:00 PM CDT) through Saturday, April 20th (2:00 PM CDT), 2024, ni.com will undergo system upgrades that may result in temporary service interruption.
We appreciate your patience as we improve our online experience.
From Friday, April 19th (11:00 PM CDT) through Saturday, April 20th (2:00 PM CDT), 2024, ni.com will undergo system upgrades that may result in temporary service interruption.
We appreciate your patience as we improve our online experience.
12-06-2007 09:16 AM
12-06-2007 10:40 AM
Yes, and your resolution will be about 31uV (2V/(2^16)).
Here's a link to the manual:
http://www.ni.com/pdf/manuals/371931d.pdf
Happy sampling!
12-07-2007 10:12 AM - edited 12-07-2007 10:14 AM
Hello Mark,
The bits of resolution on your card refers to how many different values your
Analog to Digital Converter (ADC) can have. So a 16 bit ADC has 2^16
(=65536) different values it can output over the given input range. This
means that the smallest change in input voltage that is significant would be
equal to your range divided by the number of values your ADC can convert to.
What is actually going on in the guts of the card is that the ADC has a fixed
range of -10V to 10V and can detect an ~305µV change (20V/65536). The range
that you specify controls the preamp that scales the data before it reaches the
actual ADC. So for example, our +/-1V signal would be amplified 10x
before it reaches the 16 bit ADC and then the value the ADC gives back is
scaled back down before we read it.
There are some things we do internally that make the absolute accuracy better,
so the calculated resolution will be just slightly better than the actual
resolution. I have copied table 4-1 out of the user manual
(AnalogKid2DigitalMan linked above) which shows the actual resolution for the
different ranges:
I hope this answers your question satisfactorily Feel free to post back with
any further questions.
12-11-2007 10:22 AM
12-12-2007 05:35 PM - edited 12-12-2007 05:35 PM