毕业论文交通灯毕业论文交通.doc

摘要 随着科学技术的进步和工业的发展，城市中交通量激增，原始的交通方式已不能满足要求，同时，由于工业发展为城市交通提供的各种交通工具越来越多，从而加速了城市交通事业的发展。而交叉口的通行能力又是决定道路通行的关键所在，这样一来，交通灯系统的自动化控制就显得尤为重要。可编程控制器在工业自动化的地位极为重要，广泛的应用于各个行业，它结构简单，编程方便，可靠性高。由于PLC具有对实用环境适应性强的特点，同时其内部定时器资源十分丰富，可对目前普遍使用的“渐进式”信号灯进行精确控制，特别对多岔路口的控制可方便地实现。因此现在越来越多地将PLC应用于交通系统中。 关键词：PLC 交通灯 程序 设计 目录 摘要··································································Ⅰ 目录··································································Ⅱ 1绪论··································································1 1.1引言·································································1 1.2设计目的及意义·······················································2 2 PLC的特点及应用······················································2 2.1概述·································································2 2.2PLC的特点···························································2 2.3PLC的应用···························································3 3 PLC的结构及原理······················································3 3.1 PLC的分类··························································3 3.2 PLC的结构··························································4 3.3 PLC的工作原理······················································5 4 PLC的编程语言与指令系统·············································6 4.1 PLC的汇编语言······················································6 4.2 PLC的编程元素······················································6 4.3 PLC的基本指令······················································7 5交通信号灯PLC控制系统分析与设计·····································7 5.1控制要求分析························································7 5.2 PLC选型····························································8 5.3 I/O地址定义·························································9 5.4梯形图设计··························································9 6结束语·······························································10 致谢··································································11 附录··········································