RS-485总线在泵站监控系统中的应用研究

Research on RS-485 Bus Application in Multiple PC Distributed Monitor System of Centrifugal Pump Station

在一些大型泵站中,需要由多台上位计算机通过RS-485总线同时监控多台变频器,从而实现控制多台泵驱动电机的需要,本文提出了将RS-485通信模式由传统的一主多从式网络结构拓展为多主多从式结构,并将其应用于泵站分布式监控系统。对于多主多从式RS-485总线网络结构在具体应用时所出现的问题做了详细的分析,通过在软件中添加从节点地址识别码、在各主节点与从节点之间采用多路开关切换的方法,克服了主节点中访问报文与应答报文识别冲突问题和多主节点同时刻访问总线所出现的短路问题,实现了大型泵站中多台上位计算机对多台泵驱动电机的分布式监控,在不增加成本的情况下满足了系统要求,提升了系统性能。

In view of the actual application requirements in the pump station,many host computers monitor many inverters through RS-485 bus simultaneously,and control the drive motor of the centrifugal pump. The RS-485 communication mode from the traditional mode of one master more slaves network structure to the multiple masters multiple slaves type structure is presented to apply for the distributed monitoring system. We detailedly analyze the problems in the specific application of multiple masters multiple slaves network structure of the RS- 485 bus. By adding the address identification code on the slave node,and using a multiple switching between the master node and the slave node in the software,we overcome the identification conflict problem of the access message and the response message in the master node and the short circuit problem of multi master nodes visiting at the same time,and achieve the distributed monitoring of multiple hosts to multiple motors driven by the pump in the large hydraulic pumping station. The result satisfies the system requirement and enhances the system performance without increasing cost.