Bu the output voltage cannot be set. The principle I am using is :
I read the voltages in A0 and A1, and then subtract them. this difference is then used to calculate the Resistance in the RTD.
Each side of the circuit is already a voltage divider and I am reading the voltage in the center point between each pair of resistors. If the reference voltage for the Analog Pins on the Arduino is 5V and I change them to be 1.1 or 2.6, I suspect I will get values in those ranges.
How does that improve the accuracy of the readings ?