Adaptation Of CANopen To Low-voltage Power Line Carrier Communication

In recent years, with the development of digital communication, power line communication based on the electric power grid has become one of the hot-spot subjects in today's communication research due to the following strengths: high availability, low-cost, plug-and-play, and mobility. It can be used in data communication for home networking and industry automation. But the successful application of power line communication in industrial control & automation depends on the support of associated industrial data communication protocol. As a kind of general, reliable and economical fieldbus protocol, CAN-bus has been widely used in many fields. Real-time characteristics of data transmission, remarkable transmission, error-detection and automatic retransmission built in CAN protocol make it a good option for power line carrier communication, which has some obvious drawbacks such as wide-range variant input impedance, interference and signal attenuation.However, CAN protocol itself can not meet the requirements of configuration and products interconnection in industrial control network. The corresponding application layer protocol has to be made in order to build a complete industrial fieldbus system based on CAN. To address this problem, CiA(CAN in Automation) was established to design the application layer protocol-CANopen, which has been handed to Europe Standard Commitee as a kind of new industrial field bus standard.This thesis firstly analyzed the structure and principle of the power line modem in detail. Then, it analyzed CAN and CANopen application layer, including: real-time characteristics of CAN, the core of CANopen-OD, all kinds of communication objects, the allocation of COB-ID and some device profiles. And XCANopen was brought forward for implementing of CANopen in power line communication. Then, on the reference design platform of Freescale-Agilent, XCANopen's two standard software interfaces,bottom driver and function of communication and network management based on CANopen were implemented. Successful adaption of CANopen to power line communication made the modem a standardized network module. At last, this thesis made some attempt to modify the CANopen application protocol to improve the real time performance of data communication.