Abstract: This paper describes the realization of Modbus RTU master/salve protocol based on SIMATIC S7-300 PLC point-to-point communication module. In a practical packaging control system, data is transmitted reliably and effectively. The scheme is worth promoting economic significance, for avoiding the expense of Siemens driver module of Modbus protocol.

Key words: Programmable Logic Controller(PLC), Modbus protocol, serial communication

摘要： 介绍在SIMATIC S7-300 PLC控制系统中，利用对串口通信模块的软件编程，实现Modbus RTU master/slave通信的应用。实际生产应用表明，该方案在保证有效可靠的通信质量的同时，免除购买Siemens公司Modbus协议驱动模块的格外开销，具有值得推广的经济意义。

关键词: 可编程逻辑控制器, Modbus 协议, 串行通信

CLC Number: 

• TP273