Can NI 9205 Be Used for Acquiring Signals Between 0 and 100mV?

Updated Dec 27, 2019

Reported In

Hardware

  • NI-9205

Issue Details

I have NI 9205 module for measuring voltage signals.
The product specification mentions +/- 200mV to +/- 10V. Does this mean I cannot measure signals between 0 and 100mV?

Solution

The NI 9205 can be used to measure signals between 0 and 100mV

The above mentioned statement simply specifies the available voltage input ranges to choose from. 

By choosing an appropriate measurement range for an input signal, one can achieve the best code width possible for a given ADC.

Code width, defined as "The range of analog input voltages between two adjacent transition points of an Analog-to-Digital Converter (ADC) digital output code" is represented mathematically as

Code width = ADC Range/ (2 ^ bits of resolution)

Thus, by reducing the ADC range, you can reduce the smallest change in input that the ADC can measure.