2、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。关键词：自动售货机、PLC、顺序功能图、梯形图、I/O点的分配AbstractAbstract（外语专业的需要）This thesis is the design of vending machine monitor system based on S7-200 series PLC Si
3、emens form,This paper describes the origin and development of vending machine, and its development status at home and abroad, the scheme design of vending machines were demonstrated,Introduced the PLC basic composition, characteristics and work principle,The overall design of the vending machine sys
4、tem composed of PLC S7-200 series Siemens process based on a more detailed discussion.The paper describes in detail the various hardware components of vending machines, and completed the PLC external wiring diagram.When PLC trapezoidal chart compilation, this paper uses is the Siemens PLC ladder spe
5、cial compiler software STEP7 to write.Introduces the basic principle and working process of automatic vending machine, and then to a transaction process as an example, the transaction process is divided into several blocks,Then the block programming. Specify the programmable controller in the vendin
6、g machine function.The procedure involved the vending machine work most of the process. To improve the system stability using the PLC control vending machine, vending machine can ensure the long-term stable operation.Keywords:The distribution of the vending machine, PLC, sequential function chart, l
