Calculate Smallest Change a Data Acquisition Device can Read

Updated Sep 17, 2018

Reported In


  • C Series Module Shell


  • NI-DAQmx

Issue Details

How can I calculate the code width (smallest change) of my Data Acquisition device, and is it possible to use the internal pre-amps to amplify the signal to achieve better resolution?


Use the below formula to calculate code width:

Code Width = Range/2^resolution(bit)

For example, a range of +/-10V with 16bits of resolution will have a code width of ~305uV.

The Data Acquisition devices have an amplifier before each ADC to take full advantage of the device range where you can specify and min and max value in the DAQmx API. More information can be found here.

Additional Information

Devices like the NI 9205 and 9206 offer different input ranges (such as +/-0.2V as an option), which will provide you with a better code width than devices which only offer a +/-10V range at the same number of bits of resolution.


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