【正文】 .....................................12 雙沖量控制系統(tǒng) ....................................................................................13 三沖量控制系統(tǒng) ....................................................................................15 方案選擇 ................................................................................................16 建立數(shù)學模型 ................................................................................................16 汽包水位控制系統(tǒng)的數(shù)學模型 ............................................................17 測量變送環(huán)節(jié)的傳遞函數(shù) ....................................................................18 執(zhí)行機構(gòu)的傳遞函數(shù) ............................................................................19 儀表的選擇與各變送器轉(zhuǎn)換系數(shù)的確定 ....................................................19 流量變送器轉(zhuǎn)換系數(shù)的計算 ................................................................19 給水調(diào)節(jié)閥轉(zhuǎn)換系數(shù)的計算 ................................................................20 液位變送器轉(zhuǎn)換系數(shù)的計算 ................................................................20第 3 章 硬件電路設計 .............................................................................................21 A/D 轉(zhuǎn)換電路 .................................................................................................22 I/V 變換電路 ...................................................................................................23II D/A 轉(zhuǎn)換電路 .................................................................................................24 DAC0832 的簡介 ....................................................................................25 AT89C51 與 DAC0832 的接口電路設計 ..............................................26 V/I 變換電路 ...................................................................................................27 AT89C51 對 LCD 的接口電路 ......................................................................28 聲光報警電路 ................................................................................................29 AT89C51 的最小系統(tǒng) ....................................................................................30 復位電路 ................................................................................................31 時鐘電路 ................................................................................................32 電源電路 ................................................................................................33 上位機與 AT89C51 的通信 ..........................................................................34第 4 章 軟件設計 .....................................................................................................36 程序流程設計 ................................................................................................36 系統(tǒng)主程序流程圖 ................................................................................36 系統(tǒng)的初始化子程序 ............................................................................37 A/D 轉(zhuǎn)換檢測子程序 .............................................................................38 增量型 PID 控制算法子程序 ................................................................42 D/A 轉(zhuǎn)換監(jiān)控子程序 .............................................................................46 報警子程序流程圖 ................................................................................46第 5 章 PID 參數(shù)整定及仿真 ..................................................................................48 PID 控制器參數(shù)整定 ......................................................................................48 系統(tǒng)仿真分析 ................................................................................................51總 結(jié) .......................................................................................................................54致 謝 .......................................................................................................................55參考文 獻 ...................................................................................................................56附錄 1: VI 電路仿真圖 .............................................................................................58附錄 2: 硬件電路大圖 .............................................................................................59IIICONTENTSABSTRACT(chinese) ...............................................................................................................IABSTRACT ...............................................................................................................................IIChapter 1 Introduction ............................................................................................1 This design research purpose and meaning.......................................................1 The development situation at home and abroad. ..............................................3Chapter 2 Design of the boiler steam water level ...................................................5 Dynamic analysis of steam water level control system.....................................5 Maintain normal steam water level of significance....................................5 The choice of parameters and control variables .........................................6 The dynamic characteristics of under water disturbance ...........................8 The dynamic characteristics of under steam disturbance ...........................9 Scheme of the control system .........................................................................11 Single pulse control system .....................................................................12 Double pulse control system ...................................................................13 Three impulse control system ..................................................................15 Scheme selection ......................................................................................16 Mathematical model is set up .........................................................................16 Mathematical model of steam water level system