Temperature Drift Effect And Compensation Method For High Precision Pressure Transmitter

Piezoresistive silicon pressure sensors and transmitters have been widely used in processautomation systems because of its good performance in pressure measurement. Sincesemiconductor material is sensitive to temperature, so the temperature drift of the pressuretransmitter is obvious and it must be compensated before use. At present, silicon pressuretransmitter requires more temperature compensation points and compensate time torealize high precision measurement, which restrict high precision silicon pressure transmitter’industrialization.This paper mainly focused on how to reduce the number of temperature compensatepoints and shorten the compensation time, meanwhile the accuracy and compensation passrate of the pressure transmitter must be ensured. This paper studied the temperaturecompensation problem of absolute pressure transmitter and differential pressure transmitterwhich are typical in industrial, and put forward respective compensatory plan. Thetemperature compensation algorithm of the absolute pressure transmitter is the combination ofempirical formulas and linear interpolation method.This paper first mastered the universalrule of temperature characteristics through the multiple pressure transmitter calibrationexperiments and the normalization processing for calibration data, then summarized theempirical formula of different pressure range though range partition. It has proved that thenumber of the temperature compensation points reduced 3 than before. Since differentialpressure transmitter has a large discrete temperature characteristics, so only reduce thenumber of temperature compensation points is difficult to ensure the passing rate ofcompensation. Therefore this paper put forward the concept of variable temperaturecalibration data. Variable temperature calibration data means calibrating data in thetemperature slowly changing process of the differential pressure transmitter. And this paperused BP(Back Propagation) neural network to establish the compensation model ofdifferential pressure transmitter. For BP network easy to fall into local extreme, improvedgenetic algorithm is adopted into optimize BP network. By using matlab simulation themeasured data, the validity of the algorithm is proved, ensuring the differential pressuretransmitter precision and reducing the temperature compensation time.