毕业设计
基于PLC的太阳能热水器自动控制系统的设计
摘 要
本课题研究了可编程控制器（PLC）在太阳能热水器自动控制系统中的应用。重点研究了系统的硬件构成及系统软件的设计过程。指出了 PLC 设计的关键主要是能满足基本控制功能, 并考虑维护的方便性、系统可扩展性等。在本文中经研究确定出了系统的各个工序，绘制了系统的工艺流程图；进行了系统的I/O分配和PLC的选型；根据系统设计要求设计绘制了系统的控制梯形图；绘制出了控制系统电气原理图和接线图等。
通过用PLC对太阳能热水器自动控制系统的改造，大大减少了系统对其它元器件的使用，使系统接线简单、检修维护方便快捷、可靠性提高，增进了系统的先进性。
关键词: PLC；太阳能；自动控制系统；热水器
I
毕业设计
Design of Solar Water Heater
Automatic Control System Based on PLC
Abstract
Application of PLC in solar water heater automatic control system is researched in this paper. The content of this paper on the process of system hardware constitution and the system software design is emphasized . And the key of PLC design that is to satisfy the basic control function is pointed out , meanwhile maintenance convenience and system extension are also considerated. The content of this paper is divided into four parts. In the first part, the procedure of the system is established, and then the treatment flow chart is drawed out; In the second part, The address of I/O is resigned .and the suitable PLC type is choosed. The third part, the control ladder diagram is designed according to the requirement; In the end, the electrical principle diagram and the interconnection diagram are drawn.
Through the design of the solar water heater automatic control system, the components that is used in the solar water heater automatic control system are decreased. The performance of the system is lifted, and it has the feature such as simply interconnection, rapid and easy fault detecting and maintenance, and high reliability. In a word, the system becomes more advanced because of my design.
Keywords: PLC; solar; automatic control system; water heater
II
目 录
摘 要 ........................................................................................ I Abstract................................................................................................................. II 第一章 绪 论 ............................................................................... 1
1.1 本课题研究的目的、意义 .......................................................................................... 1 1.2国内外研究现状 ........................................................................................................... 1
1.2.1 国内研究现状 ....................................................................................................................... 1 1.2.2 国外研究现状 ....................................................................................................................... 2
1.3 目前我国太阳能热水器的种类 .................................................................................. 2
1.3.1 平板式太阳热水器 ............................................................................................................... 2 1.3.2 全玻璃真空管式热水器 ....................................................................................................... 3 1.3.3 热管式太阳能热水器 ........................................................................................................... 4 1.3.4 热管—真空管式太阳能热水器 ........................................................................................... 4
1.4 研究的内容 .................................................................................................................. 5
第二章 全玻璃真空管式太阳能热水器的综述 ................................................. 6
2.1 太阳能热水器系统功能简介 ...................................................................................... 6
2.1.1 太阳能热水器组成、原理和工作过程 ............................................................................... 7 2.1.2 太阳能热水器各单元介绍 ................................................................................................... 8 2.1.3 系统的要求 ......................................................................................................................... 10
2.2 可编程控制器（PLC）简介...................................................................................... 10
2.2.1 PLC的发展历史 .................................................................................................................. 11 2.2.2 可编程序控制器的工作原理 ............................................................................................. 11 2.2.3 可编程控制器的的特点 ..................................................................................................... 12 2.2.4 PLC的分类 .......................................................................................................................... 13 2.2.5 可编程控制器应用领域 ..................................................................................................... 14
第三章 热水器控制系统的设计方案 ................................................................ 16
3.1 系统硬件的设计方案 ................................................................................................. 16
3.1.1 PLC的选型 .......................................................................................................................... 16 3.1.2 PLC硬件控制框图 .............................................................................................................. 17 3.1.3 各单元功能作用介绍 ......................................................................................................... 17 3.1.4 PLC的端口分配 .................................................................................................................. 21
3.1.5 系统电路的设计 ................................................................................................................. 22
3.2 系统软件设计方案 ..................................................................................................... 24
3.2.1 软件组成 ............................................................................................................................. 25 3.2.2 系统控制流程图 ................................................................................................................. 25 3.2.3 设计PLC控制原理（梯形图程序） ................................................................................ 30
第四章 可编程控制器（PLC）的安装、维护和检修 .................................... 31
4.1 PLC的安装 .................................................................................................................. 31 4.2 PLC系统的电源接线 .................................................................................................. 31 4.3 接地 ............................................................................................................................. 32 4.4 输入接线 ..................................................................................................................... 32 4.5 输出接线 ..................................................................................................................... 32 4.6 PLC的维护和检修 ...................................................................................................... 33
第五章 结 论 .................................................................................................... 34 参考文献 .............................................................................................................. 35 致 谢 .............................................................................................................. 36 附录Ⅰ 梯形图 .................................................................................................... 37 附录Ⅱ 指令表 .................................................................................................... 37