Research Of Protocol Conversion Module Based On CANopen-EtherNet/IP

Only the physical layer and the data link layer are defined in CAN field bus, but the usage of identifier and data in CAN message are not defined in application layer. CANopen is an open and standardized application layer protocol based on CAN, and it is widely used in industrial automation field both at home and abroad.EtherNet/IP, the abbreviation of industrial Ethernet, is a communication system which is open and suitable for use in industrial environments. It uses Ethernet with TCP/IP protocol and industrial Ethernet standard, and CIP protocol is used to accomplish real-time I/O control and point-to-point information exchange. By merging advantages of CIP and Ethernet technology, it has great development potential in the field of industrial automation network.CANopen protocol specification, especially DS301V402application layer and communication profile, is analyzed first in this paper. Then CAN-Festival, which is a protocol stack of CANopen, is analyzed. EtherNet/IP protocol and its protocol stack OpENer are analyzed too. The core of the hardware platform of the subject consists of S3C2440A microprocessor, MCP2510independent CAN controller and DM9000E Ethernet MAC controller. In addition, the circuit module is designed and implemented. The system software platform is an embedded operating system based on Linux2.6.30kernel and cross compiling is used. CAN driver based on S3C2440A microprocessor and Linux kernel, the driver interface of the protocol stack, and the main program supporting basic functions of a master defined in CANopen protocol are written. Then CAN-Festival protocol stack could be transplanted to the target platform and a CANopen master based on embedded Linux platform could be set up.An EtherNet/IP slave based on embedded Linux platform is set up on the basis of an example of OpENer protocol stack. Then two named pipes are built to achieve bi-directional data exchange between EtherNet/IP slave process and CANopen master process, which are run on Linux at the same time. By this way, communication between CANopen and EtherNet/IP network could be realized. Finally, experiments on the target platform in CANopen and EtherNet/IP network are implemented to verify the feasibility and validity of the protocol conversion module.