CAN总线和基于CAN总线的高层协议

详细介绍了目前比较流行的现场总线技术——CAN总线技术的特点，分析了CAN总线的通信模式和通信介质访问控制方式。CAN总线作为一种比较简单的协议在某些方面存在着局限性，因此，各厂商结合自己的特点在CAN协议的基础上开发了DeviceNet,CANOpen,CANKingdom,SDS等高层协议。由于DeviceNet协议的独特优势，对其进行了较为详细的介绍。同时对其他几种高层协议进行了简单介绍和比较。

CAN Bus and the Higher Layer Protocol Based on CAN Protocol

The technical features of CANbus, one of the widely used fieldbus technology,is introduced in detail.the communication model as well as the Access Control Way to the communication media is analyzed.As a simple protocol CANbus has some limitations in some aspects, so according to their own features many companies developed Higher layer Protocol (HLP) based on the CAN protocol, such as DeviceNet,CANOpen,CANKingdom,SDS and so on.In this paper the features of DeviceNet protocol is introduced in detail because of its unique advantage. At the same time the characteristics and comparison of other higher layer protocol are presented.