Research On Application Of EPA In Intelligent Instrument

In accord with the developing tendency of industrial control system, the fieldbus technology become very popular in automation field, and has grown rapidly. But since the 1980s, this technology has been held in the hands of some well-known multinational companies and monopoly of the Chinese fieldbus technology and products market.The EPA (Ethernet for Plant Automation) standard is the first fieldbus standard, which IP (Intellectual Property) belongs to our country entirely. Further more, it is embodied by IEC61158 (Edition 4) formally. It's an international standard admitted by IEC. EPA control network will be the future industrial development direction of the control system, but the EPA standards in China has just started, and the current intelligent instruments generally do not support the EPA communications. so how to make these instruments used in the EPA control network has important practical significance. The paper achieves a common solution of how to apply intelligent instrument in the EPA control network.This paper designes a EPA interface and Monitor routine that based on the C3000 process controller which has been developed successfully by SUPCON INSTRUMENT. To meet the demand of instrument extensibility, CPLD, together with RAM, was originally used to communicate internal data between the main board of instruments and EPA interface. The EPA interface will equip C3000 process controller the communication capacity based on EPA. Monitor routine equip us to operate the C3000 process controller through the computer. I accomplished the following works.(1) The actuality and trend of the fieldbus and the intelligent instrument are described, the design and development of EPA interface based on intelligent instrument is presented.(2) Contents with reference to the design in EPA standard are described, types of service are researched, associated to the C3000 process controller, the detail functions of EPA interface are analyzed.(3) The in-depth and fine analysis and expatiation of the software and hardware design of EPA interface are introduced in the paper. Based on the requirements of current industrial instruments design, many low power consumption and reliability design methods are adopted synthetically. Based on the description of EPA interface and the comparison of many methods, the blue print is established.(4) Based on the analysis of functions of EPA interface, Monitor routine is developed in Visual C++ to test these functions. Based on the in-depth analysis of Network program in Windows and comparison of many methods, the blue print is established. Functions and realize methods are analyzed based on the function of EPA interface; the flow chart of software design is presented. Methods to describe the EPA device are researched, functions of each block are analyzed deeply.(5) Methods to test the function of EPA interface and Monitor routine are introduced; the results of test are analyzed. The test showed that the C3000 process controller equipped with EPA interface can work in EPA control network well; the communication between EPA interface and Monitor routine is stable and reliable.The methods presented in the dissertation are reliable; the developments of EPA interface and Monitor routine are successful.