【正文】 onstant temperature control, so as to solve the problem of energy waste to a great extent. This design use RS 485 bus munication works which is based on USS protocol and using the Siemens TD200 to realize the humanputer interface design, and using the software made from MCGS, to carries on the theoretical analysis to the system. Verified the reliability of the design, the design can solve the problem of central air conditioning energy waste through the analysis of the design. KEY WORDS: The central air conditioning, PLC, PID, frequency converter青島理工大學(xué)畢業(yè)設(shè)計(jì)（論文） III 目 錄 摘 要 ...............................................................................................................................I ABSTRACT .................................................................................................................. II 第 1 章 緒論 .................................................................................................................. 1 中央空調(diào)的發(fā)展 .............................................................................................. 1 中央空調(diào)現(xiàn)在狀況 ................................................................................ 1 中央空調(diào)發(fā)展趨勢(shì) ................................................................................ 1 本設(shè)計(jì)的意義 .................................................................................................. 1 設(shè)計(jì)的主要內(nèi)容 .................................................................................... 1 設(shè)計(jì)的意義 ............................................................................................ 2 第 2 章 中央空調(diào)系統(tǒng)介紹 .......................................................................................... 3 中央空調(diào)結(jié)構(gòu) .................................................................................................. 3 中央空調(diào)概述 ........................................................................................ 3 中央空調(diào)結(jié)構(gòu) ........................................................................................ 3 中央空調(diào)系統(tǒng)工作原理 .................................................................................. 4 制冷原理 ................................................................................................ 4 工作原理 ................................................................................................ 4 中央空調(diào)的控制原理 ............................................................................ 4 中央空調(diào)的評(píng)價(jià) .............................................................................................. 5 本章小結(jié) .......................................................................................................... 5 第 3 章 中央空調(diào)控制系統(tǒng)的硬件設(shè)計(jì) ...................................................................... 6 變頻器 .............................................................................................................. 6 變頻器的介紹 ........................................................................................ 6 變頻調(diào)速的原理 .................................................................................... 6 變頻器的選擇 ........................................................................................ 9 使用注意的問題 .................................................................................. 10 電機(jī)的軟啟動(dòng)原理及應(yīng)用 ............................................................................ 11 軟啟動(dòng)的介紹 ...................................................................................... 11 軟啟動(dòng)工作原理 .................................................................................. 11 軟啟動(dòng)的優(yōu)點(diǎn) ...................................................................................... 11 軟啟動(dòng)與變頻器的對(duì)比 ...................................................................... 12 PLC 選型 ........................................................................................................ 12 PLC 的工作原理 .................................................................................. 12 青島理工大學(xué)畢業(yè)設(shè)計(jì)（論文） IV 西門子 S7— 200 介紹 ......................................................................... 13 溫度傳感器 .................................................................................................... 14 溫度變送器 .................................................................................................... 15 人機(jī)界面選型方案 ........................................................................................ 15 總體硬件設(shè)計(jì) ................................................................................................ 16 本章小結(jié) ........................................................................................................ 18 第 4 章 軟件設(shè)計(jì) ........................................................................................................ 20 PID 控制 ......................................................................................................... 20 PID 控制簡(jiǎn)介 ....................................................................................... 20 PID 參數(shù)整定 ....................................................................................... 20 對(duì)中央空調(diào)的 PID 控制 ..................................................................... 21 應(yīng)用軟件 STEP7 ........................................................................................... 21 plc 編程 ........................................................................................................ 22 程序流程圖 .......................................................................................... 22 中央空調(diào)控制系統(tǒng)的 I/O 分配表 ...................................................... 24 程序中使用的存儲(chǔ)器及其功能 .......................................................... 25 中央空調(diào)溫度控制系統(tǒng)程序 .............................................................. 25