PLC在冷冻干燥机的应用 二

文档字数:34158,页数:58  附任务书，开题报告，文献综述
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

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