Application And Research Of CANopen Protocol In Redundant System

CANopen is a high-level protocol which is is based on CAN bus,It is an open-ended protocol with flexible configuration capabilities and is used in embedded network developed.It has become the standard protocol of distributed automation systems which is based on CAN bus (EN50325-4),it is widely used in various industrial control areasThe CAN bus originally only designed the physical layer and data link layer of the OSI model.Common users have to deal with the data link layer with the drive program directly,in more complex applications,CAN bus can not directly fullfill the needs of interconnection configuration and product demands for industrial control network.Thus,there emerged a variety of upper-layer protocols(eg CANopen,DeviceNet and SDS,etc.).In this paper,we choose the CANopen protocol which is open,common,real-time and popular in Europe as the study object.The research has the strong theoretic significience and realistic value.In this paper,we expound the basic framework,the object dictionary,communication objects and the allocation of COB-ID of CANopen protocol first.Then we solved the key technologies(redundancy and real-time)CANopen protocol used in realistic application system.And then the application adopted the modular,structured design ideal, it divided the redundant system which is based on CANopen protocol into three parts:the hardware layer,abstract layer and protocol layer, and each part were carried out to achieve.PartiCularly in the design of protocol layer,sufficient basis for "Open-Closed" principle,each module for the details of the message syntax,the main data structures and procedures designed are achieved.We first bring forward a set of management mechanism for redundant CANopen network management protocol.Finally,based on the results of the study,the actual development of the Locomotive Depot Road Management Unit Automation System CAN communication module is designed.A debugging Platform based on the model of the Hefei Passenger Locomotive Depot was build.After testing, the module is high in real-time,reliability and is good at portability and versatility.