现场总线控制系统的网络变量通信技术

现场总线控制系统中的网络变量通信技术来源 PL C网络的全局 I/ O变量通信。不同现场总线的网络变量通信有所差异 ,这将导致其适用场合不同。这里剖析了 CAN总线 ,L onworks总线及 World FIP总线的网络变量通信机制指出 :CAN具有优秀实时性却具有不确定性 ,L onworks实时性一般而且具有不确定性 ,而 World FIP既具有优良实时性又具有确定性但却是主从方式。这些差异可作为用户设计 FCS系统时的参考

Network Variable Communication Technology of Fieldbus Control Systems

The network variable communication technology of fieldbus control system comes from the global I/O variable communication of programmable controller networks. There are some differences among the network variable communication technologies of different fieldbuses. These differences result in different applied occasions. The network variable communication mechanisms about CAN, Lonworks and WorldFIP fieldbuses are analysed. It is pointed out that the CAN possesses excellent real-time ability but time non-determinacy, the Lonworks has plain real-time ability and time non-determinacy, the World FIP possesses both good real-time ability and time determinacy, but it is master-slave mode. These differences could be regarded as references for designing the field bus control system.