The Design Of Pressure Measurement Instrument Based On DSP

With the development of sensing technology, the pressure measurement instrument that has the functions of data acquisition, data processing, digital communication and self-governing has been the demand of productive practice. Piezoresistive pressure sensor is widely used because of its high sensitivity, dynamic response, easy to miniaturization. The piezoresistive coefficient of silicon is a function of temperature and so the thermal zero drift and thermal sensitivity drift occur in piezoresistive pressure sensor, that is the main reason of causing measurement accuracy reducing. So we must take some temperature compensation measures to eliminate the measurement error.After deeply researching the characteristic of piezoresistive pressure sensor, we design a pressure measurement instrument based on the DSP chip TMS320F2812, using software compensation processing. The method which is composed by polynomial-match and Newton insert numerical value is applied to compensate the measurement results, based on the temperature parameters provided by temperature sensor DS18B20. Software compensation has the advantage of high precision, speed, good stability, high reliability, that improving pressure measurement accuracy.In this paper, the pressure measurement system with data acquisition, digital filter, temperature compensation, CAN bus communication functions, and taking anti-jamming hardware and software measures, so can measure the pressure accurately in the industrial site. The designs of hardware circuit and software program are presented.