基于VB的S7-200 PLC与上位机的串行通讯及应用

Visual Basic based serial communication between PLC S7200 and host computer and its application

在实现利用PLC作为下位机完成数据采集等功能时,PLC和上位机间的数据通讯是一关键环节,为此需要对PLC与上位机间的串行通讯机理进行研究.详细分析了西门子公司的SIMATIC S7-200系列PLC与上位机间的串行通讯原理和方法,给出了在Visual Basic环境下的PLC与上位机之间通讯程序的设计方法.设计的程序保证了在Visual Basic环境下的PLC与上位机之间的通讯,并应用于某自动卸胎机械手的设计.该方案对小规模系统具有现实意义.

While PLC serves as slave computer to realize data collection function, data communication between PLC and host computer is a key link. It is necessary to investigate serial communication mechanism between PLC and host computer. Through analyzing the serial communication principle and approach of. SIEMENS SIMATIC S7-200 PLC and host computer, the program design method for communication between PLC and host computer was given based on Visual Basic. The designed program ensures the communication between S7-200 PLC and host computer, and has been used for designing an automatic unloading tyre manipulator. The scheme has realistic meaning for small scale control systems.