基于Modbus协议的S7-200PLC主从结构的通信技术研究

摘要

In order to achieve data sharing between PLC, we take them as communication master and slave with the Modbus protocol. And S7 -200PLC has its own Modbus communication protocol library that can be easily used to set up Modbus communications network. This article explains the configuration of the master and slave in detail with the basics of Modbus protocol. Experimental results show that the data is accurate and reliable in this communication network and it has high realtime and stability.%为了实现PLC的数据共享,提出了通过Modbus协议将2台PLC分别组建成通信主站和从站的方法,而且S7-200PLC自带Modbus通信协议库,可以方便地组建Modbus通信网络.根据Modbus协议的基本要求,对该网络的主站、从站的配置做了详细说明.实验结果表明,通信网络数据传输准确可靠,具有较高的实时性和稳定性.