daq 6218 - what is the smallest change in the signal that it can detect?

[Sunny1290]

Hi,

I want to know what is the minimum analog voltage detectable by DAQ6218 which is 16 bit?

I found the following document

http://www.ni.com/white-paper/13655/en/

Here is was written "Typical DAQ devices have voltage ranges of +/-5 V or +/-10 V. The voltage levels that can be represented are distributed evenly across a selected range to take advantage of the full resolution. For example, a DAQ device with a +/-10 V range and 12 bits of resolution (212 or 4,096 evenly distributed levels) can detect a 5 mV change, where a device with 16 bits of resolution (216 or 65,536 evenly distributed levels) can detect a 300 µV change."

But if we check the specification of the DAQ6218 the sensitivity for the input range +/-10V is given as 91.6µV. (http://www.ni.com/datasheet/pdf/en/ds-9)(page no 7/18).

Can anyone please clarify about the minimum voltage detectable by DAQ6218?

thanks and regards

sanjeet

[Photon_Dan]

That sensitivity number is perhaps a bit conterintuitive. It is explained in this whitepaper.

Also, note that the accuracy numbers in the table assume 100 readings.