【正文】 種信號燈的含義作了規(guī)定。 1914 年，電氣啟動的紅綠燈出現(xiàn)在美國。 可編程控制器 (PLC)以微處理器為核心，普遍采用依據(jù)繼電接觸器控制系統(tǒng)電氣原理圖編制的梯形圖語言進行程序設(shè)計， 編程容易，功能擴展方便，修改靈活 ,而且 結(jié)構(gòu)簡單，抗干擾能力強。 關(guān)鍵詞 PLC；交通控制 ； 自動化 II Abstract Since the birth of traffic lights, its internal control system have continually been improved. Also began to design methods varied, so that traffic lights bee more intelligent. The PLC with microprocessor as the core, widely adopt ladder diagram language base on the relay contactor control system electrical schematic in programming, so that they are easy to program , to expand the functions and to amend, they have simple structure and strong antiinterference ability .Siemens PLC rich instruction, can take a variety of exports、 imports expanded, the analog input devices and munications equipment is more in line with the traffic light control system with the characteristics, to facilitate working and munications. This paper chooses Siemens PLC S7200 as the main ponents, focus on the hardware interface design , make use of the ladder diagram and the sentence form to carry out a programming , the realization of the traffic lights at the crossroads automation control system. Keywords: PLC traffic control Automation 目錄 III 摘要 .................................................................................................................................................. I Abstract ...........................................................................................................................................II 第 1 章 緒論 ................................................................................................................................... 1 課題背景 ....................................................................... 1 研究目的和意義 ................................................................. 1 本文的主要工作 ................................................................. 2 第 2 章 可 編程程序控制器（ PLC） ............................................................................................ 3 PLC 概述 ....................................................................... 3 PLC 的發(fā)展歷程 ........................................................................................................... 3 PLC 的發(fā)展趨勢 ........................................................................................................... 4 PLC 的應(yīng)用 .................................................................................................................. 5 PLC 的硬件結(jié)構(gòu) ................................................................ 6 PLC 的工作原理 ................................................................ 7 本章小結(jié) ....................................................................... 8 第 3 章 系統(tǒng)設(shè)計 ........................................................................................................................... 9 控制要求 ....................................................................... 9 系統(tǒng)設(shè)計方案分析 ............................................................... 9 硬件設(shè)計 ...................................................................... 12 PLC 的選型 ...............................................................................................................12 PLC 的 地址分配 ........................................................................................................13 PLC 的接線形式 ........................................................................................................14 系統(tǒng)程序設(shè)計 .................................................................. 15 系統(tǒng)的梯形圖 .............................................................................................................15 語句表 ..............................