The Development Of Microcomputer Electric Transducer Based On WorldFIP Fieldbus

Having replaced DCS (Distributed Control System), FCS (Fieldbus Control System) has become the tendency of automation technology. Accordingly, the intelligent instrument adopting digital transmission technology is becoming the focus in the field of automation.According to the forementioned technical background, the paper will plane to study on the field instrument based on WorldFIP fieldbus in the bottom layer, microcomputer transducer of electric variables.The protocol and features of WorldFIP fieldbus, MicroFIP component and the device WorldFIP development kit are introduced from the point of application. On the basis of analyzing we have a conclusion of its unique advantages in the power system.To seek an appropriate algorithm is an important task for improving the accuracy of microcomputer transducer of electric variables. Through comparison of all sorts of sampling methods, the conclusion is obtained: under the sampling rate of 12 point/cycle the Fourier algorithm would meet the need of both accuracy and speed. The transducer adopts M68HC12 microcontroller as the core in hardware design; The frequency measurement unit employs hardware to measure frequency. The advanced techniques are applied in it, such as synchronous sampling, high speed and high precision A/D converter. The influence of harmonics and frequency on the accuracy of measurement is considered; Self-testing method and anti-interference measures are adopted in software design. Instead of RS-485 interface, a communication board of WorldFIP whose core is MicroFIP chip, can improve communicate capability. The board can accomplish the functions specified by the physical layer and data link layer of WorldFIP protocol. We can fulfill initializing of register and writing and reading of network variables and message. And then, the transducer of electrical variables can communications with other eqiupments based on WorldFIP fieldbus.In conclusion, the transducer has higher measuring precision and powerful real-time communicate function. The study will establish favorable base for latter development of field instrument based on WorldFIP fieldbus. Zhao yingyu(industrial automation) Directed by Professor Bai yan...