坩堝熔化電阻爐溫度自動控制系統

論文編號:ZD1232   論文字數:19702,頁數:52  附原理圖，外文翻譯

 摘  要
 
 本文設計的是坩堝熔化電阻爐溫度自動控制系統。該系統利用單片機可以方便地實現對PID參數的選擇與設定；實現工業過程中PID控制。它采用溫度傳感器熱電偶將檢測到的實際爐溫進行A/D轉換，再送入計算機中，與設定值進行比較，得出偏差。對此偏差按PID規律進行調整，得出對應的控制量來控制固態繼電器、調節電爐的加熱功率，從而實現對爐溫的控制。利用8751單片機實現溫度智能控制，能自動完成數據采集、處理、轉換、并進行PID控制和鍵盤終端處理（各參數數值的修正）及顯示。在設計中應該注意，采樣周期不能太短，否則會使調節過程過于頻繁，這樣，不但執行機構不能反應，而且計算機的利用率也大為降低；采樣周期不能太長, 否則會使干擾無法及時消除，使調節品質下降。目前，單片機在各行業控制系統中普遍被采用，其構成的實時控制系統日臻完善，系統總體性能也大大提高。
 本系統對干擾信號的抑制能力較強，對溫度的測量比較準確。而且通過PID控制算法實現了對系統參數的調節，使系統的響應更加靈敏、準確。

關鍵詞  單片機   溫度控制   PID調節
 

 The Automatic Control System in Temperature in Melting  Resistance Boiler

Abstract
 What this text design is a automatic control in temperature in melting in resistance system. That system makes use of the single a machine can realizes expediently to the parameter of PID choice and set up; Realize industry process inside PID control. It adopts the temperature spreads to feel the actual the temperature of boiler A/ D that machine thermocouple will examine converts, sending into the calculator inside, proceeding with initial value the comparison, having to out the deviation. Press PID regulation to proceed the adjustment to this deviation, beg to should of the control measures control solid after electric appliances, from but regulate the heating power of the electric stove, from but realize to the control of the temperature of boiler. Make use of 8751 single a machines realizes the temperature intelligence controls, can complete automatically the data collect, handles, convert, combine the proceeding PID control to handles( the correction of each parameter number) with the keyboard terminal and manifestation, should notice in control process, adopt the kind period can't be too short, making regulate the process otherwise too multifarious, not only carry out the organization can't respond, but also the utilization of the calculator is big for lower; Adopt the kind period too long, interference can't on time dissolve, make regulate the quality descent. Single a machine is in each profession control system of widespread adoption, its component and solid hour controls the day in system perfect, make that temperature control the total function of the system to increases consumedly, the function is gradually perfect.
 The system represses the ability of the interference signal stronger, is too more accurate to the diagraph of the temperature. And pass the PID control calculate way to regulate to the system parameter, the system responds to more prompt, and accurate.

Keywords  single-chip computer   temperature control   PID adjuster

目 錄

緒  論……………………………………………………………………1
控制系統總體方案確定…………………………………………………2
 2.1 系統總體方案確定……………………………………………………… 2
 2.1.1  系統的組成………………………………………………………2
 2.1.2  系統的工作過程…………………………………………………2
 2.2 設計指標………………………………………………………………… 3
第三章   控制算法…………………………………………………………………4
 3.1 控制算法的確定…………………………………………………………4
 3.2 數學模型的建立…………………………………………………………4
 3.3 PID控制算法……………………………………………………………4
 3.4 PID參數的整定……………………………………………………………6
第四章   控制系統的硬件設計……………………………………………………9
 4.1 微處理器的選擇…………………………………………………………9
 4.1.1  8751芯片介紹……………………………………………………9
 4.1.2  時鐘電路和復位電路……………………………………………11
 4.2溫度檢測元件的選擇與冷端補償電路………………………………… 12
 4.2.1  溫度檢測元件的選擇……………………………………………12
 4.2.2  冷端補償電路……………………………………………………12
 4.3 變送器的選擇與設計……………………………………………………13
 4.4 A/D轉換芯片的選擇與接口電路…………………………………………14
 4.4.1  A/D轉換芯片的選擇…………………………………………  14
 4.4.2  A/D轉換器與單片機的接口電路………………………………15
 4.5 I/O接口擴展………………………………………………………………16
 4.5.1  可編程并行I/O芯片8255A介紹………………………………16
 4.5.2  8255A與8751的接口電路……………………………………18
 4.6 程序存儲器擴展…………………………………………………………19
 4.7 鍵盤、顯示器接口電路…………………………………………………20
 4.7.1  8255A與鍵盤接口電路…………………………………………20
 4.7.2  8255A與顯示器接口電路……………………………………22
 4.8 過零檢測電路…………………………………………………………23
 4.8.1  調功原理…………………………………………………………23
 4.8.2  過零檢測電路……………………………………………………24
 4.9 執行機構的選擇……………………………………………………25
 4.9.1  固態繼電器的選擇…………………………………………25
 4.9.2   固態繼電器的應用電路………………………………………26
 4.10 系統電源………………………………………………………………26
第五章   控制系統的軟件設計………………………………………………………28
 5.1 系統采樣周期的確定………………………………………………28
 5.1.1  香農采樣定理………………………………………………28
 5.1.2  采樣周期的選擇………………………………………………28
 5.2 數字濾波……………………………………………………………29
 5.2.1 數字濾波的優點…………………………………………29
 5.2.2  數字濾波的幾種方法…………………………………………29
 5.3 系統控制程序………………………………………………………………30
 5.3.1 主程序流程圖……………………………………………30
 5.3.2  中斷子程序流程圖…………………………………………30
 5.3.3  PID算法流程圖………………………………………… 30
結束語……………………………………………………………………………34
參考文獻……………………………………………………………………35
附錄A：系統硬件電路原理圖………………………………………………37
附錄B：程序清單……………………………………………………………38