Development of a circuit that linearizes the response of a Platinum Resistance Temperature Detector

This thesis presents the development and analysis of a signal processor that linearizes the response of a Platinum Resistance Temperature Detector, commonly referred to as RTD.

The function of the RTD Processor is to accurately measure temperature in any resistance thermometry application which uses the RTD as a temperature transducer. The characteristic change of the RTD's electrical resistance with temperature makes possible this measurement; however, a linearizing circuit is needed because the resistance change with temperature is not linear.

Calculated results show that the circuit is capable of producing a temperature inaccuracy of 0.005% of full scale temperature for 0 to 200%deg;C and 0.05% inaccuracy of full scale temperature for the range of 0 to 600°C. Experimental results confirm the linearity of the output response of the circuit and are correlated with predicted results given in this thesis. The maximum error encountered in experimentation was 0.02% of full scale temperature for the range of 0 to 200°C.