电气设备通信线路软切换

Soft switching of communication lines among electrical devices

主要介绍电气设备中可编程逻辑控制器(PLC)、变频器、触摸屏、RS-485模块及个人电脑之间实现异步通信的软切换。软切换是以单片机为控制核心,通过总线驱动器实现通信线路的连接,是无触点的切换。给出了通信连接示意图、软切换连接示意图及以AT89C51单片机为控制核心、74HC244为总线驱动器的切换电路,说明了其工作过程,单片机程序设计采用外部中断方式,给出了程序流程图。实际运行表明,所提方案可行,可用于实验室不同设备间的连接软切换。

The soft switching of asynchronous communication among PLC （Programmable Logic Controller）,transducer,touch screen,RS-485 module and PC is introduced. Taking a singlechip as the core,the soft switching realizes connections of communication lines via bus driver. Communication connections and soft switching connections are illustrated. The switching circuit,using AT89C51 as the control core and 74HC 244 as the bus driver,is provided and its working process is explained. The external interruption is adopted in the program design and the flowchart is presented. Practices show that the proposed scheme is feasible and can be applied to the soft switching of connection among lab devices.