Research Of Online Noncontact Film-Thickness Measuring System Based On DSP

With the development of modern science and technology, researchers on product engineering now pay more attention to on-line testing technology with high speed and high precision. The level of the testing directly affects the efficiency and automatization of the product line. This paper is about research on on-line testing with high speed and high precision in process of production. This paper gives a detailed introduction about our developing and designing process for online noncontact film-thickness measuring system with high speed and high precision based on DSP.Hardware design is the basis of the whole system and the other system designs must be made on the basis of it. Together with the facts, the hardware microprocessor system that made by TMS320F2812DSP chip of TI corporation is used to detect the sample signal and control the measuring system. Hardware circuit design is divided into three parts: mechanically-driven structure, microprocessor system and operation terminal. Their design principles are introduced in details, especially the microprocessor system. The interference questions of hardware design and the measure of eliminating interference signal in the subject are also introduced.High-precision design of this system including analog filter, digital filter and power selection is discussed. The virtues of digital filter compared with analog filter are simply stated. The means for digital filter in common use and their applying occasions together with the calculating formulas are stated. The program flow charts of the filters used in our system are showed.Finally, this paper also describes the monitoring software system of this device including main monitoring interface, historical data inquiring interface and parameters setting interface. Monitoring system is also one of most important parts in the device. It was designed according to the idea of beautiful interface, practical function and easy operation.