基于Modbus的多站点互联通信系统应用研究

Modbus协议是低压电气应用广泛的现场总线,生产厂商在遵循Modbus协议定义的消息结构的同时,在产品应用方面使用规则及实现方法各异。为此研究具有代表性的不同品牌的PLC、智能仪表之间的Modbus RTU通信性能,并通过开发实验案例介绍了基于Modbus RTU通信协议的底层设备的远程监控与数据共享的实现方法。实验表明,遵循不同品牌设备之间Modbus参数设置及地址对应规则,合理设置主从站通信指令的轮询规则,可以方便、可靠地实现低成本、高性能的主从式远程监控系统,具有一定的借鉴和指导意义。

Application research of multi-site interconnected communication system based on Modbus

Modbus protocol is the most widely used fieldbus for low voltage electrical applications.However,while following the message structure defined by Modbus protocol,manufacturers use different rules and implementations in product application.This paper studies the communication performance of Modbus RTU between representative brands of PLC and intelligent instruments,as well as introduces the realization method of remote monitoring and data sharing of underlying devices based on Modbus RTU communication protocol by developing experimental cases.The experiment shows that the master-slave monitoring system with low cost and high performance can be easily and reliably realized by following Modbus parameter settings and address correspondence rules between different brand devices and reasonable setting of polling rules for communication instructions of master and slave stations,which has certain reference and guiding significance.