The Research Of CANopen Protocol Based On Embedded Systems

Controller Area Network, as a kind of fieldbus, has advantages such as itsreliance, real-time, flexible and economical so that is currently used in automationindustry, production of cars, ships manufacture,and so on. CAN-bus protocol justdefines the protocol of the physical layer and the data link layer, but does not providethe protocol of the application-layer. As the application layer standards set by theInternational Organization for Standardization, CANopen has grown to become themost popular protocol of the CAN bus application layer. International organizationshave developed many excellent application program of CANopen protocol. But allthe work of the protocol stack realized by the application program increase thedifficulty of application program development. To realize CANopen protocol, thispaper will be use a kernel module, and provide call interface to application program,in order to simplify application development in CANopen system.In this paper, at first, analyzes the CAN bus and the advantages of itsapplication layer protocol the CANopen protocol, and choses ARM as its hardwareplatform, using embedded Linux operating system, designs software in Linux kernelto realize basic communication functions, such as the communication of process dataobject, the communication of service data object, the communication of networkmanagement object, the communication of special function object and so on.Secondly, designs Object Dictionary, writes Object Dictionary in the CANopennetwork, and combined with communication objects to realize full function of theCANopen protocol eventually. Finally, designs application programming interfacefor the kernel module programming, and designs a temperature acquisition systemwhich is based on the results of this paper ultimately, By the communication betweenthe CANopen master and the temperature logger based on the CANopen protocoltransport temperature data, and validate the achievements of the design in this paper.