Design of temperature measurement circuit in oxidation kinetics testing for coal spontaneous combustion tendency

High-precision measurement and record for temperature is needed in oxidation kinetics testing for coal spontaneous combustion tendency. Therefore, temperature measurement circuit was designed with high-resolution AD converter AD7714 and three-wire Pt100 thermal resistance as temperature sensor; method of piecewise linear interpolation is adopted for interpolation operation of output value to solve problem of non-strict linearity between input and output caused by nonlinearity of devices. The experiment result shows that AD sampling resolution of the circuit is high up to 0.006 7 ℃, meeting design requirements, and the experiment data has high stability and repeatability.