Resolution using PT100 RTD

[fifty60]

I am trying to determine the resolution of my temperature controller. My sensor is a PT100 RTD. The temperature range for the controller using the RTD is -210 to 700. The ADC on my temperature controller is 18 bit, with a 16 bit "actual" resolution.

So using 16 bit... I take input range/ (2^16 - 1) to get my get the actual size of the steps the input signal is quantized to. I am just not sure what input range I would use for the RTD. What would be my range of inputs for the RTD? I know the PT100 is 100 ohms at Zero C, but beyond that I do not know what to do to calculate the resolution.

 

[GoldDigger]

If the controller uses a bridge method to get the resistance, then your resolution could be as good as the total temp range divided by number of steps.
If, on the other hand, your controller applies a known current and the measures the voltage using its ADC, you need to divide the 100 ohm resistance by the number of steps and then find the ratio of that number to the change in resistance per degree. (Absolute change, not percentage)