Performance enhancement and fault identification using Kalman filter in a resistive temperature sensor interface

Abstract

In recent times, smart resistive sensor interfaces are popular. A smart two-wire interface of Resistance Temperature Detector (RTD) with fault identification feature is proposed in this study. In this method, a constant floating current source is used along with a microcontroller and 16-bit ADC. Further, Finite Impulse Response (FIR) filter and Kalman filter were implemented to filter noise. The results obtained were encouraging. Evaluation of the proposed model was undertaken and a maximum percentage of absolute error of 0.11% was observed. Further, without any additional measurements, a model-based fault identification using Kalman filter was also proposed to locate faults in the sensor and lead-wire resistances. A deliberate sensor fault and increase in lead-wire resistances were introduced to check the performance. The proposed system works reliably and promises fault identification.