Research Of Device Description Based On XML And EPA Function Blocks

Interoperability between devices of different models and different protocols is always one of the key problems that need to be solved in control system. Since the proposal of EPA standard, the existing device interoperable solutions are not suitable to EPA. So an XML-based extensible device description language--XDDL was developed. On the basis of XDDL, this thesis expanded device description elements combined with EPA function blocks to describe devices. The main work in this thesis is listed as follows:(1) A deep research on the existing EPA function blocks was done. On the basis of analysis of structure, organization and scheduling method of EPA function blocks, further analysis was conducted to communication mechanism and communication interface of EPA function blocks.(2) Comparison of advantages of XML and the application model and application process of XDDL were analyzed. Basic structure elements of XDDL are not complete and it can not describe complicated devices. This paper extended element of XDDL, designed interface module, data module and communication module, and built a description elements library preliminary.(3) Device description method based on XML and EPA function blocks was designed, and the new method was applied in the EPA configuration software. DD files management module, link objects configuration module and device management module were designed and the functions of each module were also tested.The development of device description elements library and the combination with function blocks make the description of devices more logical. The new device description method is complete and convenient to equipments developers and users.