Patent ID: 8408787

Claim:
In a process temperature transmitter, a method for providing a process temperature output, the method comprising: providing a measurement current through a circuit including a reference resistor and a resistance temperature device (RTD); measuring a first voltage across the reference resistor while the measurement current flows therethrough; measuring a first voltage across the RTD while the measurement current flows therethrough; calculating a first resistance of the RTD based on the measured voltage across the reference resistor and the measured first voltage across the RTD; providing a first process temperature output based on the first resistance of the RTD; measuring a second voltage across the RTD while a subsequent measurement current flows therethrough, the second measurement occurring after measurement of the first voltage; estimating a second voltage across the reference resistor based on the measured second voltage across the RTD and the measured first voltage across the reference resistor; calculating a second resistance across the RTD based on the measured second voltage and the estimated second voltage; and providing a second process temperature output based on the second resistance.