New thermal compensation algorithm for piezoresistive pressure sensors based on the linear approximation by segments

The piezoresistive pressure sensors are widely used in monitoring and control applications within the industrial sector. These sensors have problems of temperature dependence, and non-linearities that affect the measurement accuracy. For this reason, it is necessary to use signal conditioning circuits for to obtain high accuracy outputs. One of the most common techniques currently used to conditioning the signals from the sensors is based on the use of digital signal processors and compensation algorithms. This paper proposes a new calibration and compensation algorithm for piezoresistive pressure sensors based on the linear segment approximation with thermal compensation. The algorithm was simulated using the mathematical software MathCAD and using data from a piezoresistive pressure dummy sensor. The algorithm has been validated experimentally implementing it into two digital signal processors using vented piezoresistives pressure sensors of 10 bar in the range of temperatures from 0 degrees C to 80 degrees C. The result was that the maximum error in the sensor output due to the temperature dependence of the offset was 0,081% of full scale output. The maximum error obtained at the output caused by the temperature dependence of the sensitivity was 0,106% of full scale output. The effectiveness of the algorithm is demonstrated in the thermal compensation of piezoresistive pressure sensors. This algorithm can be applied to other types of sensors having thermal dependencies and incorporating a microprocessor or digital signal processor. (C) 2014 CIMNE (Universitat Politecnica de Catalunya). Published by Elsevier Espana, S.L.U. All rights reserved.