Is My NI 9201 Insufficient for My Data Acquisition?

Updated May 3, 2018

Reported In

Hardware

  • NI-9201

Issue Details

I am trying to read data with my NI 9201, and the values are fluctuating too much to distinguish the different corresponding data. Is my 9201 sufficient for this task? How do I know if I need a more precise device?

Solution

This could be a problem of how the DAQ is being used, or it could be a problem of precision where you need a more precise device. Our 9201 is an inexpensive option for data acquisition, and as such, there are more precise products that we offer.

Start off by figuring out the raw voltage that needs to be identified. The NI 9201 has 12 bit ADC which means it can divide its voltage range (+/- 10 V; this is a 20 volt range) down 2^12 times. Thus, you can identify at a precision of 20 V / 4096 which is roughly equal to 5 mV.

This does not mean you will definitely be able to distinguish 5 mV from 10 mV with the NI 9201, as other factors come into play affecting the device's accuracy. While some of our devices offer voltage ranges as small as +/- 200 mV, the 9201 does not offer smaller voltage ranges to increase precision.

If you find that the precision is insufficient, you may need a higher precision device, or a different sensor/probe that represents the data with less fine voltage differences. You can contact us to figure this out, and our engineers are happy to make an informed product recommendation for your specific application!

Additional Information

As per the NI 9201 datasheet, at typical conditions, its gain error is +/- 0.04% and its offset error is +/- 0.07%. These values increase as you deviate from typical conditions. Typical conditions are defined as 25 degrees Celsius (77 degrees Fahrenheit).

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