I'm looking at performing accurate temperature measurements with a three wire RTD, and I'd like to be able to measure the resistance and thus the temperature using an arduino. The accuracy I'm looking for is better than 0.1Ω @ 100Ω.
I was told that to get good accuracy, I would first need a stable accurate low current source and very accurate low temperature coefficient resistors in a wheatstone bridge.
I was wondering if there was to better utilize the arduino's capabilities to perform this measurement, or is the external current source + wheatstone bridge the way to go?
Best Answer
Source: application note AN687 by microchip. It shows one of the methods of signal conditioning for 3-wire RTD. Notice that this method doesn't require a Wheatstone bridge.