Diffused Silicon Pressure Sensor Drift Compensation Software Implementation

The diffused silicon pressure sensor using silicon piezoresistivity and micro-electronic technology is rapidly developed in last 30 years. Due to its sensitivity, high accuracy, long terms stability, easy to miniaturization, mass produced and etc. It is wildly used in petroleum, chemical, metallurgical, power industry and other sectors. But since the temperature effect of semiconductor, the performance of silicon sensor is also changed by temperature. And the pressure sensor without temperature drift can't be produced at present, so temperature compensation is a key technology in the research and production of silicon pressure sensor.This paper discusses the causation of zero and sensitivity temperature drift of diffused silicon pressure sensor from semiconductor principal and circuit principle, then introduces several kinds of software compensation methods and gives a simple comparison. Based them, a new temperature compensation system is introduced. And the hardware, software design method of this system is described in the third and fourth chapter; experimental data analysis is described in detail in the fifth chapter.This system is based on high performance micro-controller ADuC824 and C8051F31O, composed of data acquisition circuit, data processing circuit, power circuit, peripheral interface circuit and etc. ADuC824 takes charge of pressure and temperature single acquisition and AD conversion; C8051F31O takes charge of signal processing and communication. This system uses look-table and one-dimensional data interpolation method compensates nonlinearity and temperature drift in 2 steps. Experimental data indicates that the nonlinearity is from 0.1 %FS to 0.05%FS after compensation. And zero and sensitivity temperature drift is also reduced deeply. Through this intelligent node, the analog output is converted to digital singal output, so has long transmission distance and strong anti-jamming ability. This node can be linked to PC or intelligent instrument by using RS232 bus, make the traditional pressure sensor can be used in accurate networked measuring and controlling.This compensation method has a lot of advantages, such as low cost, simple software and hardware design, full-function, excellent compensation effect, flexible expansion, high integration and stabilization, is simple to install, debug and detect and etc, and will be used widely in automated data acquisition and controlling.