基于PLC的电梯控制系统——软件设计

摘要

随着现代经济和城市生活的发展，电梯成为人们日常生活必不可少的代步工具，电梯性能的好坏对人们生活的影响越来越显著。传统继电器电梯控制系统，由于继电器本身的机械和电磁惯性大，大大降低了电梯系统的可靠性和安全性。为了保证电梯运行既高效节能又安全可靠，必须改进电梯控制方式。根据顺序逻辑控制的需要发展起来的可编程控制器（PLC），它是专门为工业环境应用而设计的数字运算操作的电子装置。PLC处理速度快，可靠性高，能够保证电梯正常、安全、可靠地运行。同时，由于电机交流变频调速技术的发展，电梯的拖动方式己由原来直流调速逐渐过渡到了变频调速，不仅能满足乘客的舒适感和保证平稳的精度，还可以降低能耗，节约能源，减小运行费用。本文将基于PLC的变频调速方法应用到电梯系统中，并对此方法进行研究。

首先，分别阐述了电梯继电器控制和PLC控制的特点，突出讲述继电器电梯控制系统暴露的缺点以及PLC电梯控制系统所具有的优点，并对电梯的变频调速控制进行了介绍。其次，在阅读了大量国内外相关文件资料的基础上，对电梯技术和电梯设备的发展进行了综述。然后，介绍了变频器类型以及参数设计的相关知识；同时介绍了PLC选型原则以及PLC控制系统的设计思路；在此基础上，根据电梯系统自身的工作状态要求，进行电梯系统的PLC软件开发，通过软件开发的特点，结合PLC自身的控制规律，设计出可实现一定功能的PLC电梯控制系统。最后的模拟调试结果表明，基于PLC的变频调速电梯系统运行效率高，系统安全可靠性强，并且系统构造简单易于实现，满足了对电梯系统期望的要求。

关键词：电梯，可编程控制器，变频调速，旋转编码器

Abstract

Along with the development of modern economy and city life, the elevator has become a

essential walking tool for people in daily life, and the performance of elevators obviously in

flue nces people 'lives. The traditi onal elevator system basedo n relay largely decreaseshe reliability and security since the mechanicaland electromagneticinertia of relay is big In order

to ensurethe efficiency and reliable securities,the control method of elevator must be changed. The programmable logic controller(PLC),which develops based on seque ncelogical con trol, is

digital operati on electro nic device specialized in the in dustrial application environment. PLC possessesfast process speedand high reliability. Therefore, PLC can be able to en surethe elevator r un no rmally, securely a nd reliably .In additi on. The drive method of elevators has replaced the DC velocity modulation with frequency control due to the developmentof AC frequency control of motors. The frequency control not only satisfiesthe comfort senseof passengersand ensuresthe

stable precision, but also decreases the loss of power, savesresourcesand reducesexpenses.The frequency control method based on PLC is applied to the elevator system a nd further researched.

Firstly, the essayrespectively prese ntsthe characteristicsof the elevator system based on relay control and PLC control, specially formulates the defects exposed from relay control system and the advantagesof PLC control system, introduces the frequency control of elevators. Secondly, based on reading many domestic and international relative literatures. The developme ntof elevator tech niq uesa nd elevator devices is overviewed. And the n,the relative knowledgeof frequency^converteris introduced;the principle of PLC model election and designschemeof PLC control system are introduced aswell. On the basis of these,the PLC software of elevator system is developedaccordi ng to the work ing statesdema ndsofthe elevator. A elevator system based on PLC control is designed through combining the characteristics of software developme nt and the rules of PLC con trol. Fin ally, the an alog exam in ati on shows the elevator freque ncyc on trol basedo n PLC possesse^nigh operati onal efficie ncy and stro ng system security. The system structure is simple a nd easily realized, a nd satisfiesthe dema ndsof the elevator system expected.

Key words: Elevator, Programmable Logic Control(PLC), Frequency Conversion & Velocity

Adjustment, Revolving Encoder

摘要......................................................................... I Abstract ............................................................................. II