The Thermal Drift Compensation And Nonlinearity Revise Of The Pressure Sensor

Pressure sensors are widely used because of a low price. The intelligent pressure sensor, based on microprocessor technique, are popularized because of convenience and accurate measurement Silicon resistance is the core of pressure sensor , An intelligent pressure sensor acquires, processes data by using microprocessor technique. The piezoresitive coefficient of silicon is a function of temperature and so the offset drift and sensitivity thermal drift occur. The factors affecting on temperature are various: the change of measurement environment, the heat of the measurement circuit and so on. If we want to get accurate pressure values, they must be revised.The sensor offset is governed by its thermal drift, electric drift and time drift, so eliminating the offset thermal drift in the measurement of sensors requires to keep the values of resistance and temperature coefficient for different resistor strips to be equal each other. This paper will discuss how we can revise the offset by curve matching so that the sensor price will fall and its accuracy will be improved.The pressure sensitivity is proportional to the piezoresitive coefficient and the later is a function of temperatures ,so after eliminating sensitivity thermal drift , the nonlinearity can be substantially compensate. The methods, diode compensation, constant current compensation, thermal sensitive resistor compensation and so on are widely used. This paper has got an analytical expression with temperature information by curve matching technique , by this means, we can not only predigest hardware circuit but also realize the function of selfrevision and selfcompensation.In addition, based sensor thermal drift and nonlinearity principle, this paper has designed intelligent sensor hardware circuit and edited a software program . The circuit with micro-process is simple and cheap , though the result has still a little error.