摘要自从交通灯诞生以来，其内部的电路控制系统就不断的被改进。设计方法也开始多种多样，从而使交通灯显得更加智能化。可编程控制器(PLC)以微处理器为核心，普遍采用依据继电接触器控制系统电气原理图编制的梯形图语言进行程序设计，编程容易，功能扩展方便，修改灵活,而且结构简单，抗干扰能力强。西门子可编程控制器指令丰富，可以接各种输出、输入扩充设备，有丰富的特殊扩展设备，其中的模拟输入设备和通信设备更是符合交通灯控制系统的要求与特点，能够方便地联网通信。本文选择西门子可编程控制器S7-200为核心部件，着重进行硬件接口设计，利用梯形图和语句表进行编程，实现了十字路口交通灯控制系统的自动化。关键词PLC；交通控制；自动化AbstractSincethebirthoftrafficlights,itsinternalcontrolsystemhavecontinuallybeenimproved.Alsobegantodesignmethodsvaried,sothattrafficlightsbecomemoreintelligent.ThePLCwithmicroprocessorasthecore,widelyadoptladderdiagramlanguagebaseontherelaycontactorcontrolsystemelectricalschematicinprogramming,sothattheyareeasytoprogram,toexpandthefunctionsandtoamend,theyhavesimplestructureandstronganti-interferenceability.SiemensPLCrichinstruction,cantakeavarietyofexports、importsexpanded,theanaloginputdevicesandcommunicationsequipmentismoreinlinewiththetrafficlightcontrolsystemwiththecharacteristics,tofacilitatenetworkingandcommunications.ThispaperchoosesSiemensPLCS7-200asthemaincomponents,focusonthehardwareinterfacedesign,makeuseoftheladderdiagramandthesentenceformtocarryoutaprogramming,therealizationofthetrafficlightsatthecrossroadsautomationcontrolsystem.Keywords:PLCtrafficcontrolAutomation目录摘要..................................................................................................................................................IAbstract...........................................................................................................................................II第1章绪论....................................................................................................................................31.1课题背景........................................................................31.2研究目的和意义..................................................................31.3本文的主要工作..................................................................3第2章可编程程序控制器（PLC）............................................................................................32.1PLC概述........................................................................32.1.1PLC的发展历程...........................................................................................................................32.1.2PLC的发展趋势...........................................................................................................................32.1.3PLC的应用..................................................................................................................................32.2PLC的硬件结构.................................................................32.3PLC的工作原理.................................................................32.4本章小结........................................................................3第3章系统设计............................................................................................................................33.1控制要求........................................................................33.2系统设计方案分析....................
