S7-22×PLC在扭矩仪系统开发中的应用

The Application of S7-22×PLC in the Development of Torque-preload Testing Machine

介绍了扭矩仪以及S7-22×PLC在该系统开发中的应用。根据系统功能要求分析和介绍了系统的控制功能图、系统软件编程思路以及PLC程序功能模块。在开发中主要采用了基于PC的控制系统,但是PC机不能直接驱动电机,需要借助于PLC或单片机。而后两者在数据处理、存储、显示等方面的功能又不及前者。实践中采用了PLC。自由口协议就是在自由口模式下用户可以自己定义协议来与其他智能设备进行通信。自由口模式支持ASCII和二进制协议,实践中采用了ASCII协议,即通信中发送的是ASCII码。自由口通信把PC机和PLC的优点结合在了一起,只需要PC机向PLC发送相关指令,PLC即可按照要求去驱动电机。而这并不妨碍数据采集和处理模块的并行运行,提高了系统的可靠性和响应及时性。

This paper gives an introduction on Torque-preload testing machine and the application of PLC in the development of it,on which analysis about controlling system, system programming method as well as PLC programming modules are also presented. The controlling system based on PC is introduced in the development,however,PC cannot drive motors directly without PLC or MCU,which are not so good as the former on data processing, data saving as well as data diplaying.Thus,PLC is adopted to control motor with free-port protocol which is defined by users who want to realize communication between PLC and other Intelligent systems,Such as PC.In freeport mode,it provides two kinds of protocol：ASCII and Binary, and the former is used during the work,in which ASCII codes are transmitted.Self-defined protocol takes both the advantages of PC and PLC,by which,PC sends a series of instructions and PLC will run as required.At the same time, it dosen＇t disturb data acquisition and processing,thus,which improves the reliabihty and lower the response time of the whole system.