The Research Of Earthnet Control System And Protocol Analyze

NCS (networked control system) is one of distributional control system based on network. It is one of the hot spots in Control field combined with latest computer technology, communication and control technology, showing the advantage of networking, integration, and intellectualization. NCS uses real time network to integrate with field inspect apparatus and control and operation equipment in order to form one feedback control system. NCS provides data transmission among equipments, and let users of different site in the same region sharing data resource and coordinated operation. It is the extension of computer network system into control field. And the usage of it will become more and more popular with the scale of Control system.This paper trace back the development of NCS, introduced the characteristic and mathematical mode of it. Discussed the problem and solution with NCS including time delay, sampling rate, the network data packet discards. analyzed CSMA/CD and CSMA/CD—TDMA media access protocol, simulated Ethernet control system based on CSMA/CD and give a contrast result with system based on CSMA/CD—TDMA, at last, we provide a new protocol model which have both advantage of this two protocol, and get a satisfactory result with simulation.