Research Of Intelligent Transmitter Based On EPA -Ethernet For Plant Automation

Communication networks for industry are most quickly developed in current industry automation fields. As a communication link of intelligent devices, based on standard communication protocols, the open networks technology integrate dispersive devices with communication function, such as intelligent transmitters, actors, intelligent contral devices, workstations, to a comprehensive information plant and realize the integration of field control, supervising and managing, optimizing and decision-making. In process industry, the most important control parameters----pressure and different pressure usually are measurerd by prssure or different pressure transmitter.This paper sums up outlines the states of the art of fieldbus and Ethernet for the automation in the world, analyzes the characteristic and usability of communication networks used in industry. It makes detailed research on the key techonlogy of precise intelligentized pressure and different pressure transmitter with EPA (Ethnet for plant automation) function: (1) research on the field-instrument in which EPA is embedded. (2)research on the communication determinability of EPA intelligent transmitter。(3) research on the technology for temperature compensation of EPA intelligent transmitter by software to adapt to enviroment change. This paper presents full solutions of EPA intelligent transmitter, EPA embedded communication circuit board signal processing, environment compensation based on Neural Networks super precision. Based on these solutions, a pattern has been accomplished.Through strict performance test, determinability test of communication, and precision compensated test, the pattern has been proved to achieve a hight precision, determinate communication and to accord with the EPA standard. This pattern was integrated with EPA system locating in the National engineering center for control system (Zhejiang University) and positively judged by national expert-group at 863 items in 2005.Research on EPA intelligent transmitter has acquired the following domestically advanced achievements: EPA embedded communication technology, test for EPA instruments, power supplied on bus, hight precision detection, software compensation arithmetic and so on. These achievements provide an advanced and practicable solution to the EPA networks communication technology and intelligentized automation...