【作者】 何万里； 隋江华； 任光；

【Author】 He Wan-li Sui Jiang-hua Ren Guang(Marine Eng. College,Dalian Maritime Univ. Liaoning, 116026,China)

【机构】 大连海事大学轮机学院；

【摘要】 在许多对时间要求很严格的应用中都需要一个精确的实时时钟。如分布式控制中的测试设备就需要一个精确到毫秒级的实时时钟。集中式控制系统达到毫秒级非常容易,但是在分布式控制系统(例如连接在CAN-bus上的传感器和执行机构),由于他们没有全局的时钟节拍,使系统达到毫秒级的同步就很困难。这个问题可以通过在一定的精度内同步所有的节点时钟来解决。本文提出了一种应用再总线上时钟同步协议,并且以CAN-bus为例在实验室中得以实现。经验证该协议能够提供一个大约10毫秒的同步精度。该协议简单且不需要额外的硬件,它只是占有一定的带宽(<20个信息/每秒)。如必要也可在大型网络中达到与外部时钟基准同步的要求。更多还原

【Abstract】 much time critical applications, e.g. the measurement devices in distributed control system, require a real-time clock with an accuracy of microseconds. In a centralized system it is easy to implement the requirement, but in a distributed system (like a number of sensor and actuator nodes connected via the CAN-bus), this is more difficult as there is no global system tick. Synchronizing the local clocks of all nodes with a sufficient accuracy can solve this problem. This paper offers a clock synchronization protocol on the CAN-network and implements it in the lab. The results show this protocol can reach the accuracy of 10 microseconds. The protocol is simple and hardware-independent; it uses only a small amount of bandwidth (<20 messages/second). If necessary, e.g. in large scale networks, the protocol can be synchronized with an external time-base.更多还原