文档介绍：毕业设计(论文)
院系名称:电子信息学院
班级:电子051
学号:
学生姓名:
指导教师:
2009年 5月
摘要
近年来,交流变频调速技术在各行业的应用发展迅速。由于变频调速在调速范围、动态响应、低频转矩、功率因数、效率等方面是以往的交流调速方式无法比拟的,并且在节约能源、提高经济效益等方面都发挥了巨大作用。信息技术的飞速发展,引起了自动化系统结构的变革,使以网络为主干的自动化分布式控制系统成为行业趋势。所以基于网络控制的交流调速系统越来越广泛应用于工业生产中。
本文主要论述基于西门子PLC及其网络的交流调速系统设计。设计用PLC控制MM440变频器的手动/自动控制方案。手动控制用端子控制方式,由外接数字开关控制变频器的端子,以实现电动机的正转、反转、点动等,由外接的电位器控制MM440的频率,从而达到控制电动机转速的目的。自动控制采用网络控制方式,PLC和变频器之间采用PROFIBUS-DP通讯,PLC通过发送任务报文的形式来控制变频器的输出,通过接收应答报文的形式来监测变频器的状态。采用网络控制方式,简便可行,系统稳定,节约线缆,可实现远距离控制。网络控制在现代交流调速系统的应用中具有重要意义。
关键字:PLC 变频器通信网络
Abstract
In recent years, the AC frequency converter technology applications in various industries have developed rapidly, Frequency control is better than the past AC frequency in some aspects, such as the speed scope, dynamic response, low-frequency torque, power factor, efficiency. And it plays a significant role in energy conservation,
Improvement of economic results and so on. The rapid development of information technology has caused changes in the structure of automation systems, so that the distributed control system of automation which work as the background to e industry trends. Therefore, the AC speed governing system based on work more and more widely used in industrial production.
This paper discusses the AC speed governing systerm based on the SIEMENS PLC and it’works. It is to control the macromaster440 in manual / automatic way by S7-400PLC. The manual control mode is to control terminals. It not only can control the digital switches from the external terminal of the inverter in order to achieve the motor ’s transfering, reversing, moving, alarming and so on, but also can control the MicroMaster440 by controlling the external potentiometer is to control the AC motors’ speed . The automatic control code is to control it in the way works. PLC and inverter municate by PROFIBUS-DP .PLC can control the inverters’ outputs by sending the assignment messages. And PLC can supervise the status of inverters by receiving the re