The Application Of Embedded Ethernet Technology In Fieldbus

The Ethernet technology is developing quickly , and will get many effects such as reducing cost, predigesting structure if we apply this technology to the industrial control field . Embedded system becomes a new hotspot of industrial control field because of its advantages such as small volume , many functions and supporting Ethernet technology . Embeded system is generally independent of Internet , but with the development of technology and the increase of practical demands , it must be a great impulsion to the development of control field to let them combine.Fieldbus now is one of the development hotspots in automatization field , and it is named the computer LAN of this field . CAN(Controller Area Network)as one fieldbus is a kind of serial communication net, which can effectively support distributed control or real-time control. Comparing with some distributed control systems based on RS485 , the system based on CAN bus is better in the ways of good stability , high speed , multi-host structure . CAN bus now has been used in many fields , and is rivalrous .This thesis introduces a system which connects with the underlayer I/O node through CAN bus interface and links direct with Internet , can be accessed through Internet by warranted users , and can supervise the underlayer equipments .The thesis introduces some technologies such as CAN bus , TCP/IP , and lays stress on introducing the whole design plan , questions need to be thought over , design principles of hardware and software . Otherwise , some are particularly introduced such as two kinds of CAN mode , ARP , ICMP , IP , UDP , TCP among the TCP/IP protocol family .A software is introduced in this thesis which is programmed using Visual Basic. We give a conclusion about this system and its disadvantages and talk about the future of this technology.