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1、自动售货机控制系统设计1、总体设计方案1.1、总体设计思路自动售货机的基本功能就是对投入的钱币数进行计算，然后根据运算结果做出相应的判断，看看哪种商品可以进行购买，哪种商品不能购买，本次课程设计的要求是可识别三种钱币，分别是1元、2元、5元，采用三个按钮进行模拟，自动售货机共出售四种货物，其价格分别定为1元、3元、4元、6元，当投币数大于等于货物价格时且售货机里有这种货物时，指示灯亮，表示可以进行购买，四种货物分别用四个小灯代替进行模拟。除此之外，本次设计还涉及了显示、找零、送货等功能的实现，其中显示部分采用数码管进行显示，显示投币总数和购买后的余额；当按下找零按钮后，数码管显示进行清零，采用
2、从高到低递减的形式进行清零，例如：当余额为17元时，按下找零按钮后，先找三个五元数码管分别显示12、7、2，然后再找2元，清零。送货部分采用小车直线运动进行模拟，将四种货物分别送到四个不同的地点，采用四个光电开关分别代表四个不同的送货地点，当按下不同的送货按钮后，小车会以其对应的光电开关为终点做直线往返运动，表示送货过程由于售货机的全部功能是在上位机上模拟的，所以售货机的部分硬件是由计算机软件来模拟替代的这些并不会影响实际程序的操作，完全能模拟现实售货机的运行。1.2、PLC总体设计流程以下为PLC的一般工作过程流程图。 图一 PLC工作过程流程图2、硬件设计我们本次采用的是西门子公司的S72
3、00系列PLC，它可以提供4种不同的基本单元和6种型号的扩展单元，其系统构成包括基本单元、扩展单元、编程器、存储卡、写入器、文本显示器等。2.1、I/O地址分配本次课程设计的主要I/O分配如下：表一 I/O地址分配输入单元PLC地址输出单元PLC地址投币1元I0.1A货物显示Q1.0投币2元I0.2B货物显示Q1.1投币5元I0.3C货物显示Q2.0送货（A货物）I0.4D货物显示Q2.1送货（B货物）I0.5找零出口Q2.2送货（C货物）I0.6出货口Q2.3送货（D货物）I0.7电机正转Q2.6找零I0.0电机反转Q2.5数码个位显示I0.0I0.3数码十位显示I0.4I0.7限位开关S1
4、I1.0限位开关S2I1.1限位开关S3I1.2限位开关S4I1.32.2、中间继电器分配 表二 中间继电器分配中间继电器功 能中间继电器功 能M0.0送A货M1.2电机反转M0.1限位开关S1M1.3电机正转M0.2限位开关S2M1.4电机正转M0.3送B货M1.5电机反转M0.4送C货M1.6电机正转M0.5限位开关S3M2.0送货延时M0.6送D货M2.1送货延时M0.7限位开关S4M2.2送货延时M1.0电机反转M20.0找零M1.1电机正转2.3、整体系统工作流程整个系统的整体工作流程如图二所示图二 整体工作流程图2.4、硬件接线图 图三 硬件接线图2.5、实物接线图图四 实物接线图
5、3、软件设计4、程序调试在整个程序的调试过程中，我遇到了一些问题，最初的设计比较简单，只是将投币，购买的过程考虑进去，而没有将购买之后送货的过程加进设计的方案中，后来在老师的提醒之下，我又将送货的过程采用了小车直线运动进行模拟，将四个光电开关模拟成四种货物的送货地点，分别在按下四个送货按钮之后，将货物送到四种地点，使得整个系统更加完善，功能更加强大。在数码显示的过程中也遇到了一些问题，数码显示时数据的传输所用到的中间继电器和后来送货时的中间继电器发生了冲突，使得程序运行过程发生了紊乱，后来在同学的帮助下，我明白了问题的关键，将其解决，使数码显示功能顺利实现。在最后的送货过程中，由于有四个地点，
6、所以要对电机的正反转分别进行控制，最初我是将所有的正转输入都采用了Q2.6进行驱动，所有的反转输入都采用了Q2.5进行驱动，当程序运行时，发现得不到预期的现象，经检查程序没有问题，后来经过考虑和同学的提醒，采用中间继电器进行驱动，现象就出现了，实现了最初预想的送货过程。在找零阶段，最初只是按下找零按钮后直接将数码显示清零，后来经过思考和老师的提醒，将找零部分又逐步进行了完善，将找零的过程在数码管上显示了出来先找大面额的钱币，后找小面额的钱币，其内部进行减法运算，使得整个找零的过程清晰可见。在购买货物的过程中最初忽略了如果货物售完该怎么办，后来经过完善将货物的数量进行了设定，只有当投币金额大于等
7、于所要购买的货物时，且货物数量大于零时才能进行购买，这使得整个过程更加完善。g an employment tribunal claiEmployment tribunals sort out disagreements between employers and employees.You may need to make a claim to an employment tribunal if: you dont agree with the disciplinary action your employer has taken against you your employer dism
8、isses you and you think that you have been dismissed unfairly.For more information about dismissal and unfair dismissal, seeDismissal.You can make a claim to an employment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. However, if you win you
9、r case, the tribunal may reduce any compensation awarded to you as a result of your failure to appeal.Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are complaining about happened. If your application is received
10、after this time limit, the tribunal will not usually accept i.If you are worried about how the time limits apply to you, take advice from one of the organisations listed underFurther help.Employment tribunals are less formal than some other courts, but it is still a legal process and you will need t
11、o give evidence under an oath or affirmation.Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an employment tribunal, you should get help straight away from one of the organisations listed underFurther help.If you are being represente
12、d by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case. This is known as adamages-based agreement. In England and Wales, your solicitor cant charge you more than 35% of your compensation if you win the case.If you
13、are thinking about signing up for a damages-based agreement, you should make sure youre clear about the terms of the agreement. It might be best to get advice from an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by e-mail,
14、click onnearest CAB.For more information about making a claim to an employment tribunal, seeEmployment tribunals.The (lack of) air up there Watch mCayman Islands-based Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will at
15、tend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport.For me its about how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the ra
