24小时无人售货的系统-毕业论文.doc

中文摘要 自动售货机可完成无人自动售货，不受任何场地限制，方便快捷，可以每天24小时售货，随着自动售货机数量的增加，商品包装的定量化和标准化，出售的商品多样化，自动售货的便利性日益显现。现在，自动售货机产业正在走向信息化并进一步实现合理化。例如实行联机方式，通过电话线路将自动售货机内的库存信息及时地传送各营业点的电脑中，从而确保了商品的发送、补充以及商品选定的顺利进行。本论文设计的是基于西门子S7-200 系列PLC构成的自动售货机控制系统，本文阐述了自动售货机的来源与发展，以及它在国内外发展的现状，对自动售货机的方案进行了论证，介绍了PLC的基本组成、特点以及工作原理，对基于西门子S7-200 系列PLC构成的自动售货机系统整体设计过程进行较为细致的论述。 文中详尽地介绍了自动售货机的各硬件组成，并完成了PLC外部接线图。在PLC梯形图的编写时，文中采用的是西门子PLC梯形图专用编译软件STEP7来进行编写。介绍了自动售货机的基本原理以及工作流程，然后以一次交易过程为例，把交易过程分为几个程序块，然后分别对程序块进行编程。具体说明了可编程序控制器在自动售货机中的作用。程序涉及到了自动售货机工作的绝大部分过程。利用PLC控制的自动售货机提高了系统的稳定性，保证自动售货机能够长期稳定运行Vending machine is to be completed no automatic vending, without any space restrictions, convenient and sales 24 hours a day, with the increasing number of vending machines, packaging and standardized quantification of the sale of various goods of automatic vending convenience becomes obvious. Now, vending machine industry is moving towards information and further rationalization. For example, the implementation of on-line, through the telephone line within the vending machine inventory information in a timely manner all business point of sending the computer to ensure the goods to send, add, and the smooth progress of the selected goods. This thesis is based on Siemens S7-200 series PLC control system consisting of vending machines, vending machines This paper describes the origin and development, and its development status at home and abroad, on the vending machines program was demonstrated, PLC introduced the basic components, characteristics and working principle, based on Siemens S7-200 series PLC vending machine system as a whole constitute the design process more detailed discussion.  The paper describes in detail the various hardware components vending machines, and completed the external wiring diagram of PLC. PLC ladder in the preparation, the article is used special compiler software, Siemens STEP7 PLC ladder to be prepared. Introduced the basic principles of vending machines and work processes, and then to a tr