Study On Device Description Technology In The EPA System

With the breakthrough of communication determinism and intelligent switch technology and higher bandwidth, In industry automation system communication network upon control level gradually unify to Ethernet for industry, and which is in process of extending to field device level and carry out that the network framework only consist of Ethernet for industry, In the progress, Item group which is sponsored by "863" Program develop the EPA (Ethernet for Plant Automation) distributed and real-time control system. In order to solve the interoperability and integration of devices of different manufactures, EPA item group research existent DD technology and characteristic of industry Ethernet in all aspects, and develop a DD technology-extensible Device Description Language, and apply successfully it to field device integration in EPA system. But people study few on device description application and the device description technology based on XDDL still have disadvantages because the research on XDDL technology is at the begin.The paper firstly study deeply description method based on XDDL and intergration element based on device description documents in XML format, then study device description application on storage and share and remote access of device profile information and design application model on XDDL document applied to EPA system based on characteristics of XDDL and EPA network, We draw advantages and disadvantages of XDDL After study on device description based on XDDL and compare to other device description technologies.then design a method to expand device description based on XDDL to make up disadvantages of describing complex configuration process and usage and diagnosis methods of complex device and represent device characteristics in graphics mode. It describes complex configuration process and usage and diagnosis methods of complex device and represents device characteristics in graphics mode base on software module and extended XDDL with self-define tags. It extend XDDL with self-define tags to describe interface function information, and describe complex configuration process and usage and diagnosis methods of complex device and represent device characteristics in graphics mode in software module in DLL(Dynamic link Library). Application in the engineer station load DLL software module dynamically and call the function in the DLL with the interface information provided by XDDL document, thus integrate and manage all devices and their software modules.At last I develop VC++ application to validate and implement the method to expand device description based on XDDL in the flowmeter based on EPA protocol platform, experiment testify that the method is compatible with XDDL, it not only describe common device with XDDL in text but also discribe the complex function of complex device in codes. It better combines cost of device and integrality of function.