（毕业设计论文）《PLC在谷物烘干机自动控制中应用》.doc

摘要 PAGE IV 精品 PLC在谷物烘干机自动控制中应用 摘 要 谷物烘干机是一种自动化程度要求较高的机电设备，应用于农业生产中农作物烘干领域；它通常采用继电器逻辑控制方式，设备的电控系统故障率高，检修周期长。随着技术的进步，这类控制系统已显示出越来越多的弊端。近年来，PLC机在工业自动控制领域应用愈来愈广，它在控制性能、组机周期和硬件成本等方面所表现出的综合优势，是其它工控产品难以比拟的。因此在工业控制领域，随着电力电子技术、可编程序控制器与变频技术的发展，以PLC控制为核心的电控技术在各类机械设备中的应用越来越广，它将逐渐取代传统的继电器控制系统，上升为交流电气控制的主流。PLC作为谷物烘干机的核心控制器，其在工业过程控制中体现了强大功能。当前，PLC在国际市场上已成为最受欢迎的的工业控制畅销产品。本篇论文论述可编程控制器PLC对谷物烘干机自动控制：主要介绍谷物烘干机工艺流程，PLC控制系统的设计、梯形图、程序编制等。 关键词：PLC、谷物烘干机、自动控制 PLC IN THE DRYER IN THE AUTOMATIC APPLICATION ABSTRACT In recent years, PLC automatically control the industry and application,it is in control of the performance,the cycle and hardware cost of the aspects of the comprehensive and other industrial control products incomparable.For industrial control,power electronic technology,programmable controller to control the development of the PLC to the core of the electrical control technology in various types of mechanical equipment in the use of more and more widespread, it will gradually replace the traditional relays control system for communication in the mainstream of the electrical control.PLC industry in recent years in the control and wide application in to control the performance, the cycle and hardware cost of the aspects of the comprehensive and other industrial control products incomparable. this thesis deals with PLC programmable controller for the dryer machine is automatically controlled: mainly introduces the dryer process,PLC control system design and the structure, procedures etc. KEY WORDS: PLC, grain drying machine, automatic control 前言 目 录 TOC \o 1-3 \h \z \u HYPERLINK \l _Toc264115646 前 言 PAGEREF _Toc264115646 \h 1 HYPERLINK \l _Toc264115647 第1章 方案的比较及PLC的发展趋势 PAGEREF _Toc264115647 \h 2 HYPERLINK \l _Toc264115648 1.1谷物烘干机的介绍 PAGEREF _Toc264115648 \h 2 HYPERLINK \l _Toc264115649 1.1.1 PLC控制电路的优点 PAGEREF _Toc264115649 \h 2 HYPERLINK \l _Toc264115650 1.1.2 PLC的发展趋势 PAGEREF _Toc264115650 \h 3 HYPERLINK \l _Toc264115651 第2章 PLC简介 PAGEREF _Toc264115651 \h 4 HYP