Research And Design Of Smart Sensor For Pressure Measurement

With the development of computer control system, especially of the system with multi-sensor, the intelligent sensor or smart sensor, as a new research field, is attracting more and more people's attention. Although some achievement in the field has been obtained recently, the results are far from application requirements, even worse in the measurement of pressure area. With the development of a pressure control system, the existing traditional pressure sensor has not met the need, however the smart sensor that has the functions of data collection, information processing, digital communication and self-governing has been imminent demand of the development of productive practice. After the theory of smart sensors for pressure measurement has been deeply studied, a new kind of a smart sensor for measuring pressure is developed in this paper to improve this situation, and its overall design of intelligent functions and hardware and software are also described in detail. A microprocessor with powerful functions and higher integration is used as the main control unit. Large numbers of analog and digital peripheral circuits have been also integrated inside, so the microprocessor has the powerful ability of data processing. All components of the sensor, some of which are necessary for the multiple and intelligent functions, are selected ones with low cost and small package. All circuits are designed in a piece of PCB and the PCB is installed with the pressure detector together. The smart sensor then obtains the advantages of small dimension, low cost and higher anti-disturbance ability. Based on deeply research for the intelligent functions of the pressure sensor, the sensor's intelligent software with better quality is designed. Some intelligent characteristics, such as automatic gain control, temperature compensation, automatic calibration, digital communication by bus, etc. have been realized, which makes the sensor have higher level of intelligence. A temperature compensation algorithm according to the behavior of the inductance sensor, and a nonlinear compensation algorithm are designed. Anti-disturbance and system self-diagnosis of the sensor have been well designed, therefore the stability and reliability are guaranteed. A kind of intelligent digital filtering algorithm with program judgment is proposed here. The performance of not only better filtering, but also faster response is then obtained. The system software adopts programming language C++Builder. It takes advantage of numerous visual controls and kinds of powerful control resources supplied by the third part to make users work on a visual operating platform. The system communicates with PC to finish the functions such as data conversion, data processing, real-time data display etc. then it is convenient for realizing the central control. The smart sensor for measuring pressure designed in this paper has the advantages of small size, low cost, higher performance and response speed, and higher level of intelligence. After debugging the software and hardware of the smart sensor through emulation, the result shows that its performance is perfect. So we expect that the smart sensor can have broad future applications in many measuring and controlling systems for pressure.