Hello,
Changing the input voltage range does have the effect of changing the accuracy of your readings. Since the board has a certain bit resolution, the smaller the range, the smaller the voltage difference that can be measured.
i.e. 12-bit board -> 2^12 = 4096 : +-10V range -> 20V/4096 = 4.88 mV
Of course, this resolution of the board is not the only characteristic that will determine the accuracy. To find to absolute accuracy for your device, I recommend either going to www.ni.com/manuals to look up this information, or to go to the Accuracy Calculator found at http://www.ni.com/advisor/accuracy/ and play around with the options.
There is no way to configure default settings when creating global channels in MAX, however, you can also programmatic
ally create global channels inside of LabVIEW. This way, you can set the range you desire inside of LabVIEW instead of MAX.
I hope this information helps.
Jared A.