基于PLC的电梯控制系统的设计毕业设计论文.doc

PAGE 毕业设计说明书 PAGE PAGE 76 毕业设计说明书 基于PLC的电梯控制系统的设计 摘 要:随着现代城市的发展，高层建筑日益增多，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，因此必须努力提高电梯系统的性能，保证电梯的运行既高效节能又安全可靠。传统的电梯曳引电动机采用接触器来实现电动机工作状态的改变，双速异步电动机在定子回路中串电抗与电阻来实现电动机的调速，这满足不了乘客的舒适感；另外，传统的电梯控制系统由继电器接触器控制逻辑组成，存在着电气元件多、功能弱、电气故障频繁，可靠性差和工作寿命短等缺陷。可编程控制器（PLC）是根据顺序逻辑控制的需要而发展起来的，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。鉴于其种种优点，目前，电梯的继电器控制方式已逐渐被PLC控制代替。同时，由于电机交流变频调速技术的发展，电梯的拖动方式已由原来直流调速逐渐过渡到了交流变频调速，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。因此，PLC控制技术加变频调速已成为现代电梯行列的一个热点。 采用PLC对电梯信号系统进行控制，开发出了完整的电梯控制软件，提高了电梯的控制水平，并改善了电梯运行的舒适感，使电梯达到了较为理想的控制效果。该系统具有先进、可靠、经济的特色。该电梯控制系统具有司机运行和无司机运行即手动和自动的功能，并且具有指层、厅召唤、选层、选向等功能。具有集选控制的特点。 关键词:电梯 双速异步电动机 PLC 变频调速 集选控制 Design of the elevator control system is based on PLC Abstract：Along with developing modern city,increasing high building,the elevator is beginning to play a vital role for walking tool in everyday life,therefore the performance should be improved for both economy and efficiency.As far as the comfort sense concerned,the traditional motor uses the contactor to shift its operating state,and the double-speed asynchronous motor strings reactance together with resistance in the stator to alter its velocity modulation,which could not meet passengers criterion.Moreover,the traditional control system is composed of the relay、contactor and control logic,which brings such defects as: excessive electrical parts,weak function,over-frequent electric failure,low reliability and short life etc.The programmable logic control (PLC) is designed specially for industry environment,which is being developed based on the requirement of sequential logic control. Herein,cause of its all merits,the elevator’s relay control mode has been replaced by the PLC gradually.At the same time,as a result of the development of motor AC frequency inverter’s technology,the elevator’s driving mode has been replaced gradually by it from the original DC frequency control,which can not only meet the passengers comfort criterion,guarantee st