Research On Communication Interface For Fieldbus Based On Ethernet

Compared with other fieldbus technology, Ethernet technology provides the advantages of being open, simple structure, low cost, easily extended frequency, and good compatibility. Herein, in recent years, Ethernet technology has been extensively applied in the upper industrial control. However, up to date, there is not so much report on the application of Ethernet technology in the bottom networks of industrial control as the fieldbus. Though the application in this respect can remarkably promote the development of fieldbus, greatly improve the transmitting speed and simplify the types of used fieldbus.This dissertation firstly introduces the latest development in fieldbus, and after comparing and analyzing the today's several main fieldbus technology in depth, it points out the existent problems in these fieldbus technology. Referring to the up to date research on the application of Ethernet to the fieldbus, it proposes a solution to standardize the transmitted information in the field on the application level of Ethernet. According to this solution, the requirement of real-time in field communication can be fulfilled as a result of its message service and short frame structure. To complete this idea, this dissertation reports the design for an embedded Ethernet module for data exchange between RS-232C and Ethernet communication with a micro-controller W78LE516B and a network card driver chip RTL8019AS. This Ethernet module can be directly used to convert the RS-232C information mode to Ethernet information mode or be embedded in the equipments controlled by microprocessors. Afterwards, this dissertation introduces the designing of hardware circuit and compiling of corresponding driving program in detail. This design simplified the TCP/IP without changing its main structure to meet the demand for real-time and reliability in field communication. In the end of this dissertation, the general frame for embedded TCP/IP, process of frame packing, and the procedure in sending and receiving data are comprehensively analyzed.In this project, an embedded Ethernet module was designed and the data exchange between RS-232C protocol and Ethernet protocol was fulfilled with this module. At the same time, based on the modular programming method provided by C language, an embedded TCP/IP was realized with MCU. This embedded TCP/IP has highly real-time and can be transplanted easily. After debugging, it turns out that the designed embedded Ethernet module is of the particularities of high integration, high reliability and low costand can be used to supervise and access the remote equipment in real time...