| With the development of computer control system, especially of the system based on fieldbus 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 measurement of displacement area. After the theory of intelligent sensor having been deeply studied, a new kind of intelligent sensor for measuring displacement is proposed in this paper to improve this situation, and its overall design of intelligent functions and hardware and software are also described in detail.1.A small and cheap 8-bit microcontroller is used as control core. 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. By designing all auxiliary logic circuits in a complex programmable logic device (CPLD), and integrating all analog circuits in an application specific IC (ASIC), the size of PCB board is greatly reduced, which make it possible that the PCB can be installed with the displacement detector together. The intelligent sensor then obtains the advantages of small dimension, low cost and higher anti-disturbance ability.2.A new kind of inductance sensor for displacement with new square-wave driving mode and signal processing circuit is proposed. It overcomes the disadvantages of traditional inductance sensor, and has advantages of small size. light in weight, better linearity, long life, higher frequency response property and simple driving and signal processing circuit, etc.3.Having considered the situation that the human-machine dialog equipments in some computer control systems are not of high quality, a new kind of reorganizing the sensor~s system by external human-machine dialog scheme is presented in this paper. By using PC as an external human-machine dialog component. the senSor's system can be reorganized by human-machine dialog on the spot. which makes the sensor have more flexible ability to suit many applications. After being used a lot of times, the result shows it has the ad~ antages of high performance and reliability. low cost and easy to use.4.Anti-disturbance and system self-diagnosis of the sensor have been well designed, therefore the stability and reliability are guaranteed. A kind of intelligent dhtital filtering algorithm with program judgment is proposed here. The performance of not only better filtering, but also faster response is then obtained.VI5.Based on deeply research for the intelligent functions of the sensor, the sensor's intelligent software with better quality is designed. Some intelligent characteristics, such as automatic gain control, temperature compensation, automatic calibration, data fusion, digital communication by fieldbus, etc. have been realized. which makes the sensor have higher level of intelligence. A Temperature compensation algorithm to overcome cross sensitivity according to the behavior of the inductance sensor, and a system self-calibration algorithm to overcome the drift of the analog circuit are designed. On the basis of these two algorithms, a new kind of data fusion algorithm combing both of them is derived out. Secondly, a kind of fieldbus communication scheme with higher efficiency is proposed to enhance the sensor's communication ability by fieldbus with simple hardware. In addition, multi-output mode is also designed for the sensor, which enlarges its application area.6.The new concept of digital calibration for intelligent sensor is presented, and programs for computer aided calibration and debugging are designed. With the help of these programs, the calibration of sensor is made visual, simple and more accurate. So, the development, debugging, usage and maintenance of the sensor become easier. It could be a powerful tool for future research of the sensor.The intelligent sensor for measuring displacement designed in this paper h...
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