论文编号:ZD171 包括开题报告,任务书,文献综述,三菱系列PLC 论文字数:34117,页数:59
摘 要
冷冻干燥机广泛应用于生活生产中，像制药方面、食品保鲜等方面。制药方面是很早就应用的， “绿色食品”的兴起，食品保鲜已引起了广泛重视。然而，在运作中，传统的冷冻干燥机暴露了越来越多的问题，比如：触点过多、故障出现频繁、维修不方便，影响了冷冻干燥机的正常工作，引起产品质量降低。
围绕一系列的问题，人们研究许多方法，PLC以其优越的性能吸引了众人的眼光。
本文介绍了使用计算机和PLC 组成的冻干机自动控制系统,叙述了计算机监控软件的设计和实现,程序采用了多线程技术和自定制的串口通讯类,取得了良好的效果。
关键词: 冷冻干燥机;多线程;通讯;监控系统
Abstract
The freeze drier has been used in many factory。For example pharmacy respect，preserve freshness。The pharmacy respect is used very early. When " green food " springs up, preserve freshness. The food is preserve freshness to arouse widely to value. However，Being living to transport to be a middleman .Traditional freeze-dry engine revealed more and more problems。Such as too many tip, therefore the block has made out frequently。The maintenance is not convenient. It effect the regular work of freeze-dry engine。It cut down the produce quality。
Revolving round a series of problems, people research much means, and PLC attract the foresight of crowd with such advantageous performance
A control system for a freeze drier based on PC and PLC is introduced, emphasizing on the design and implementation of the computer monitoring and control software. The techniques of multithreading and a self-made module of communication class were adopted in the program, the feasibility of the system was proved in its applications.
Key words: freeze drier; multithreading; communication; monitoring and control system
目 录
摘要……………………………………………………………………………………………1
Abstract…………………………………………………………………………………….…1
绪论…………………………………………………………………………………2
1.1 可编程控制技术的发展现状与特点………………………….…………….2
1.2 冷冻干燥机简介…………………………………………………. …………7
1.3 课题来源与主要研究内容…………………………………….. ………….17
第二章 PLC控制冷冻干燥机总体设计………………………………. …………………17
2.1 概述…………………………………………….……………….. …………17
2.2 设计方案的选择………………………………….…………….. …………17
2.3 最佳方案的选择…………………………….………………….. …………18
2.4 PLC控制的优势………………………………….…………….. …………18
第三章 硬件的选择………………………………………………………………………..20
3.1 PLC及显示设备的选择……………………………………….. ………….20
3.2 可编程控制器外围装置、设备与接口……………………….. …………24
3.3 传感器………………………………………….……………….. …………26
3.4 确定I/O点……………………………………………….…… …………31
3.5 PLC及扩展模板……………………………………………….. ………….31
第四章 控制系统软件设计………………………………………………. ………………37
4.1 系统软件设计系统总流程图………………………………….. ………37
4.2 软件的组成与结构………………………………………………………..38
4.3 各部分子程序……………………………………………………………..39
4.4 总的控制梯形图…………………………………………………………..42
第五章 通信子程序的设计………………………………………………………………..44
5.1 PLC与计算机通信方式…………………………………………………..44
5.2 VC实现串口通讯的方法………………………………………………….48
致谢…………………………………………………………………………………………..53
参考文献……………………………………………………………………………………..54
附录 PLC程序……………………………………………………………………………..55
