Measuring resistance values in temperature sensor - measuring voltages across resistance and reference resistance for null and constant currents

摘要

The method involves passing a constant current through the measurement resistance (R1) and a reference resistance (RR1), the voltages across the resistances are measured and converted into digital form. The digital signals are interpolated to determine the resistance value. The voltages across the resistances are measured with zero current to enable compensation fo the offset voltages of switches in series with the resistances. Theses voltages are digitised and subtracted from the digitised values of the voltages corresponding to the constant current to produce the values used to compute the resistance value. ADVANTAGE - Reduces errors caused by switch-dependent offset voltages.