Intelligent differential pressure transmitter with a multiple sensor formed on (110) oriented circular silicon diaphragm

A multiple piezoresistive gauge sensor was developed for application to intelligent differential pressure transmitters. The sensor can measure three quantities, i.e., differential pressure, static pressure, and the temperature. Three piezoresistive gauges are positioned on a (110) plane crystallographic silicon diaphragm. Proper dimensional design and optimal gauge positioning maximize the output and minimize the crosstalk. Three voltage outputs are combined by a microprocessor unit using data maps to yield a compensated sensor output. An experimental sensor was fabricated, and the compensation scheme via simple processing proved to be useful. The accuracy was within ±0.1% of the full scale in the pressure range of ±80 kPa. The drift was less than 0.25% for the temperature change of 50°C and was less than 0.1% for the static pressure change of 15 MPa