知识竞赛抢答器PLC毕业论文设计精选.doc

本科毕业论文（设计） 题目：知识竞赛抢答器PLC设计  摘 要 随着我国经济和文化实业的发展，在很多公开竞争场合要求有公正的竞争裁决，诸如证券、股票交易及各种智力竞赛等，因此出现了抢答器。最初的抢答器是由优先权编码器构成的逻辑电路，其运算速度慢，线路复杂，可靠性不高，功能也比较简单，特别是当抢答路数很多时，实现起来就更加困难。因此，一种能够体现竞赛的公开、公平、公正性的知识竞赛抢答器成为一种需求。 本设计将以PLC为核心设计了系统结构图、程序指令、梯形图以及输入输出端子的分配方案，在保留了原始抢答器的基本功能的同时又增加一系列的实用功能并简化其电路结构，其将以其控制方便，灵活，只要改变输入PLC的控制程序，便可改变竞赛抢答器的抢答方案，从而使得竞赛不断完善其公平、公正性。 关键词：PLC；知识竞赛抢答器；七段数码器；IO分配  Abstract With the development of our country economy and cultural industry,public competition requires a fair adjudgement in many occasions,such as securities and ruling stock trading and various intelligence contest etc, resulting in various responder. First vies to answer first is composed of priority encoder which is constiuted by logic circuit, the speed and reliability of it is not high and the circuit is complex, but the function is simple. especially when there are many responders, it is more difficult to achieve. Therefore, a responder to reflect a kind of openness, fairness and impartiality of the knowledge competition is a kind of demand occupations. The core of this design is based on PLC ,it is composed of system structure diagram, procedures, ladder-diagram and the allocation of input and output terminals,the design not only retains the basic function of the the original responder but increases a series of practical function and simplifies the circuit structure, it will be easy and flexible to its control, as long as change the PLC control procedures, you are able to change the program of the competition responder, making the competition fair and justice. Key words：PLC; The knowledge competition responder;7 digital device;IO distribution 目 录 1 绪论 1 1.1 课题研究背景 1 1.2 课题研究内容 1 1.3 可编程控制器概论 2 1.3.1 PLC的简介 2 1.3.2 PLC的用途 3 1.3.3 PLC的特点 4 1.3.4 PLC的分类 5 2 整体方案的选择 7 2.1 整体功能介绍 7 2.2 竞赛抢答器的控制要求 7 2.3 用单片机和PLC分别做系统的比较 8 3 硬件电路设计 10 3.1 控制特点分析 10 3.2 PLC机型的选择步骤与原则 10 3.3 流程图 12 3.4 PLC与七段LED显示器连接设计 12 3.4.1 LED数码管的结构及主要特性 12 3.4.2 PLC与七段数码管方案选择 13 3.4.3 PLC与七段数码管直接连接阻值计算 14 3.4.4 外部硬件接线图