【正文】 ................................................... 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(shè)計 ............................................................................... 36 程序流程設(shè)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 III 參考文獻 ............................................................................................. 56 附錄 1: VI 電路仿真圖 ....................................................................... 58 附錄 2: 硬件電路大圖 ....................................................................... 59 IV CONTENTS ABSTRACT(chinese) ............................................................................ I ABSTRACT ..........................................................................................II Chapte r 1 Introduction ...................................................................... 1 This design research purpose and meaning ................................. 1 The development situation at home and abroad. ........................ 3 Chapte r 2 Design of the boile r steam water level .............................. 5 Dyna mic analysis of steam water level control system ............... 5 Maintain normal stea m 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 Sche me selection ................................................................. 16 Mathematical model is set up .................................................. 16 Mathematical model of stea m w ater level system ............. 17 Measuring the transfer function of the part ....................... 18 The transfer function of the actuator ................................. 19 Instrument selection and deter mination of coefficient .............. 19 The calculation of transmitter conversion coefficient ....... 19 The calculation of water regulating conversion coefficient 20 The calculation of transmitter conversion coefficient ....... 20 V Chapte r 3 Hardware circuit de sign ................................................ 21 A/D conversion circuit ............................................................. 22 I/V transform circuit ................................................................ 23 D/A conversion circuit ............................................................. 24 The summary of DAC0832 ................................................ 25 AT89C51 and DAC0832 interface circuit design ............... 26 V/I conversion circuit .............................................................. 27 AT89C51 interface circuit of LCD ........................................... 28 Sound and light alarm circuit ................................................... 29 The minimum system of AT89C51 ........................................... 30 Reset circuit ...................................................................... 31 Clock circuit ...................................................................... 32 Power supply circuit .......................................................... 33 Upper machine munication with AT89C51 ........................ 34 Chapte r 4 Software design .............................................................. 36 Program design ........................................................................ 36 The system main program flow chart ................................. 36 The initial system, antifuzzy process ............................... 37 A/D conversion detection subroutine ................................. 38 Increment type PID control calculate w ay ......................... 42 D/A conversion control subroutine .................................... 46 Alar m subroutine flow chart .............................................. 46 Chapte r 5 the PID parameter setting and the simulation ............. 48 The PID controller parameter setting ....................................... 48 System si mulation analysis .......