There are two common PLC methods for the control of converter.One is used I/O ports to transfer signal,the other is bus communication.There are many advantages,such as wiring saving,various control functions,fast transmission speed,long transmission distance and so on,for the PROFINET field-bus,which has been widely used in the automatic control field.In order to implement the communication between PLC and converter based on the PROFINET filed-bus,it is necessary to set up the parameters of inverter G120,to set up the hardware configuration of PLC and converter,to write the communication program for sending and receiving data,and then to carry out the conversion and judgment program.The whole process of program designing and debugging is very complex,and requires abundant knowledge and experience of real application.Because of the difficulty of understanding,the students are hard to master the communication between PLC and converter.This article gives an example of PROFINET communication of S7-300 series PLC,the touch panel TP700 and the converter G120.The example can help to explain the method and set the parameters of G120,to describe the hardware configuration method and the programming skill of PROFINET network.The discussion and results of this article can improve the knowledge and technology levels of students,hence,are helpful to improve the ability of students in using the studied knowledge for solving the practical problems.%PLC控制变频器的常用方法有两种.一种是I/O端口传递信号,另一种是总线通信.PROFINET现场总线具有省配线、控制功能多、传输速度快、传输距离远等诸多优点,因此在自动化控制领域得到广泛应用.为了实现基于PROFINET现场总线的PLC和变频器通信,需要对变频器众多的参数进行设置,对PLC和变频器进行硬件组态,编写程序收发通信数据并对其进行换算、判断.在G120相关参数设置的基础上,以S7-300系列PLC、触摸屏TP700和变频器G120的PROFINET通信为例,阐述PROFINET通信网络的硬件组态方法和程序设计技巧.本文的研究结果有助于提高学生的知识技术水平和理论应用于实际的能力.
展开▼
