Research On PLC Network Communication Technology And Its Applications In TFT-LCD Business

With the development of industrial control technology and network communication technology, programmable logic controller (PLC) networking communications in industrial automation is playing an increasingly important role.Base on the PLC networking and industrial Ethernet technology, the field automation device can be integrated into enterprise information system, and build a close communication from the bottom device to the top management, to improve enterprise automation and information level.PLC manufacturers actively developed PLC network communication technology, set up their own PLC network system,such as Siemens PROFIBUS network, Mitsubishi MELSEC network, Rockwell ControlNet network and Omron Controller Link network, the PLC network developed by incompatible communications technologies, which result in different brands of PLC networking and communications inconvenience. Japan Electrical Manufacturers' Association advocated FL-net network is an open FA control network, using standard communication protocols to facilitate the implementation of different brands of Japanese PLC network communication. This is a Japanese factory automation industry to adapt to different manufacturers through the network communication between the models done in an effort to standardize.This thesis mainly research Japan Omron and Mitsubishi company PLC network communication technology. And established LCD panel production line real-time monitor system based on PLC network communication technology. The main research contents are as follows:Firstly, the basic knowledge of the network communication technology was introduced; including data communications infrastructure, LAN infrastructure, Omron and Mitsubishi PLC network architecture and communication systems, etc.Secondly, selected Omron and Mitsubishi representative network to research, including Ethernet, Controller Link, MELSECNET/H and FL-net of network architecture, network protocols, network functionality and implement its communication methods. Thirdly, the two tier communication network of ethernet network and FL-net network was built based on the enterprise intranet. And the data communicaton was implemented on the two tier network by setting network parameters and programing.Fourthly, established monitor system of TFT-LCD panel production line based on FL-net, and give PLC network communication implement method, including product selection, networking, parameter setting and programming method. After actually debug in the workshop, it was showed that this new system has realized efficient real-time monitor, to improve the production line automation level, and provide practical and theoretical basis of PLC networking and enterprise informatization.