1、本科畢業設計（外文翻譯）題 目基于PLC鍋爐溫度控制系統姓 名 楊宗豪專 業自動化學 號指導教師金楠鄭州科技學院電氣工程學院二。一三年十二月外文翻譯原文:基于PLC的鍋爐溫度控制系統的研究摘要：從鍋爐的發展情況，PLC選型，系統軟硬件設計，上下位機通信，組態 程序開發設計等幾個方面進行介紹。通過PLC實現的溫度控制系統具有調試簡 潔、價格低廉、易于維修等優勢，并且容易拓展到相應的工控領域，移植性較好 對工控發展具有重要的意義。關鍵詞：PLC;傳感器；溫度；自動控制隨著經濟的不斷發展，環境問題越發突出。鍋爐作為供熱系統中最重要的能 源轉換裝置能源消耗巨大，每年全國鍋爐燃燒消耗的能源占總產1/3以

2、上。目前， 國內大部分城市供熱系統中運行的鍋爐設備陳舊老化基本依靠人工操作，自動化 水平低下，安全性能極差，燃燒效率不高，空氣污染極為嚴重。因此，為鍋爐配 置自動化溫度控制系統在當今環境污染日益嚴重的情況下就顯得極為重要。1基于PLC的鍋爐溫度控制的介紹本系統是基于PLC的鍋爐溫度控制，通過鍋爐內部傳感器對溫度、流量等參 數的反饋來對系統溫度進行調控，實現鍋爐溫度的自動控制。PLC可編程控制器是一種將繼電器控制器和計算機結合起來，通過安裝程 序,CPU中央處理單元為核心與I/O設備相連接，使用在工控領域的計算機其構 成與普通計算機略有不同，主要是由CPU、存儲單元、I/O接口電路、電源等基 礎

3、部分，外加擴展部分、編程器、外部設備等方面組成。PLC可編程控制器既能 替代普通的繼電器，又具有多種擴展功能，如A/D模塊等。因此，PLC的運用為 鍋爐的自動控制提供了新的解決辦法，使一些先進的控制方法得以應用。使用PLC可編程控制器對鍋爐系統進行改造，實現對溫度的自動控制，一方 面可以提高燃燒效率，減少燃料的使用量和煙氣中有害氣體的排放，減少了空氣 污染；另一方面，PLC控制系統通過各種傳感器檢測鍋爐內溫度、壓力、流量等 相關參數，實現了對溫度等參數的自動控制。減少了人工勞動環節，基本上只需 在機房控制室內就可以全面了解整個鍋爐的運行情況，降低了人力成本、提高了 系統的自動化管理水平。2溫度

4、控制系統設計2.1溫度控制系統方案設計本設計以西門子S7-300可編程控制器為下位機，兩臺工業控制機為上位機。 上位機通過工控軟件實現報警等預警功能，下位機采用西門子S7-300可編程控 制器，實現鍋爐內溫度、流量等自動控制，控制水平及安全性得到保證。系統被控對象為溫度，利用PT100型熱電阻傳感器檢測鍋爐內部水溫，然后 通過溫度變送器傳給EM235模塊，轉換完信號經過PID的運算，調節后得到一個 穩定的PID參數值，然后輸入信號到可控硅的電壓調節器來控制加熱器的電壓， 達到調節溫度的目的。2.2溫度控制系統硬件設計1）主機系統。使用兩臺工業控制計算機構成主機，其中一臺作為主要控制 機，另外一

5、臺為輔主機，構成雙保險。組態軟件使用西門子工控組態軟件 WINCCSP26.0O2）PLC可編程控制器。系統選用西門子公司SP-300PLC的可編程控制器。 其模塊化結構，易于實現分布式的配置以及性價比高、電磁兼容性強、抗震動沖 擊性能好，使其在廣泛的工業控制領域中，成為一種既經濟又切合實際的解決方 案。多種性能遞增的CPU和豐富的且帶有許多方便功能I/O擴展模塊（包括信號 模塊SM、通信處理器CP、接口模塊IM等）。用戶可以根據實際應用選擇合適的 模塊。3）儀表設備。為了提高抗干擾能力，選用型儀表儀表DDZ-IH輸出為0123 45mA電流，保證系統的可靠性。儀表主要包括：流量變送、器壓力變

6、送器、溫 度變送器、液位變送器、含氧量變送器、微壓變送器等。4）變頻控制室。主要包括：電源控制柜、鍋爐變頻控制柜、循環泵變頻控 制柜、控制柜內配有各樣型號的斷電器接觸器、繼電器等，低壓電器設備以完成 電機的啟動、停止。2.3溫度控制系統軟件設計PID指令算法PID控制器根據系統參數的誤差值,通過比例積分、微分計算出控制量來進 行控制，故稱為PID控制，或者PID調節。在工控領域中，PID至今仍在廣泛使 用。三種控制量各有特點，單獨存在時優點與缺點都很明顯，一起使用時又會有 各種約束限制的問題，如何調節出穩定的PID參數，就成為目前控制中最為重要 的步驟。PID控制算法的特點1）比例（P）控制。

7、比例（P）控制是最簡單的一種控制方式，其控制器的輸 出與輸入誤差信號成比例關系。若產生偏差，控制器就發生作用調節控制輸出， 使被控量向減小偏差的方向變化。偏差減小的速度由比例系數Kp來決定，Kp越 大偏差減小的越快。但這樣會引起振蕩，特別是在遲滯環節比較大的時候，比例 系數Kp減小振蕩發生的可能性就會減小，但同時也會導致調節速度變慢。比例 控制的缺點是不能消除穩態誤差，必須要有積分控制來輔助。2）積分（I）控制。在積分控制中控制器的輸出與輸入誤差信號的積分成 正比關系。進入穩態后，如果控制系統存在穩態誤差，為了消除系統中存在的穩 態誤差，必須加入積分項。隨著時間增大，積分項也會增大，因此即便誤

8、差比較 小積分項也會隨著時間的增加而加大，它的存在會進一步減少穩態，誤差直至為 零。所以比例積分（PI）控制器可以使系統進入穩態后無穩態誤差。3）微分（D）控制。在微分控制下，控制器輸出的微分增加了，輸入誤差信 號的微分同時也會增加。而自動控制系統在對于誤差的控制來說，會出現別的不 必要的問題比如波動更嚴重的會失穩。這就是說，在控制器中僅引入“比例”項 往往是不夠的。比例項的作用僅是放大誤差的幅值，但是加入的微分項卻能夠避 免較大的誤差出現。因為它可以預測誤差變化的方向，但是微分控制會放大高頻 噪聲，降低系統的信噪比，導致系統抑制干擾的能力下降。也就是說微分控制不 能消除余差。PID參數整定P

9、ID參數整定主要是調節P，Pi，Pt。改變系統的各項特性，使得系統達到 滿意指標。PID算法程序實現在SP-300中PID功能是通過PID指令功能塊來實現的，通過定時執行PID 功能塊。按照PID運算規律，根據當時的給定，比例-積分-微分數據，計算出控 制量。PID程序設計PLC控制程序是采用西門子編程軟件S7V5.3來實現。首先輸入模擬信號，將鍋爐的當前電壓通過數值顯示出來。其次觀看鍋爐目 前溫度是否正常，報警指示燈是否能正常使用。啟動程序，觀察啟動后位置，初 始化PID參數，關閉程序，清零模擬量，停止鍋爐繼續加熱但仍顯示溫度。設定 溫度值，中斷程序，調節PID參數，輸出PID運算結果，輸出

10、模擬信號。4組態模塊設計1）組態軟件設計。本系統的組態設計部分軟件選擇是西門子WINCC組態軟 件，WINCC是一種功能強大，具有很好的開放性的軟件。各種復雜的任務，WINCC 均可以處理好。WINCC屬于人機界面的組態工具，其最大的特點是能夠以組態方 式進行系統集成。只要將預設的各種軟件模塊進行簡單組態，就可以輕松實現監 控層的各項功能，縮短了系統集成時間，提高了工作效率。WINCC組態軟件以微軟系統作為平臺，提供強大的編輯功能，而且本身載有 豐富的圖形資源，方便設計各種工業用圖，而且方便編輯，同時因為與計算機的 通用性，減少了工作量。用戶可以自行設計編輯函數，充分利用了開放性功能。 由于都

11、屬于西門子公司，在使用WINCC組態軟件時可以輕松對S7-300PLC系統中 的變量進行創建，編輯及修改，極大的方便用戶。2）上下機位通信。將PLC與計算機連接，連接完成后在軟件上設置通信。3）系統調試。上下位機連接完成后，反復調整溫度控制PID參數，以便得到最 佳PID參數值。系統中出現震蕩現象，通過加入微分調節，多次調試后得到最佳 PID參數。5結束語本系統采用單回路PID控制，通過多次調節PID參數,得到一個響應快速， 高精度控制的鍋爐溫度控制系統，完成了預定目標。由于使用組態設計的界面， 使得本系統更加簡潔實用，對溫度的控制更加靈活便捷，并且可以拓展到相關工 控領域。Based on

12、the research of PLC temperature control system of boilerAbstract: from the development condition of boiler, PLC type selection, system software and hardware design, communication up and down a machine, the configuration program design is presented in several aspects, such as. By the temperature cont

13、rol system of PLC debugging the advantages of the simple, low cost, easy to maintenance, and easy to expand to the corresponding field of industrial control, good portability is of great importance to the industrial developmentKey words: PLC; The sensor; Temperature; The automatic controWith the con

14、tinuous development of economy, the environment problem increasingly prominent. Boiler as the heating system is one of the most important energy conversion device energy consumption is huge, every year the national boiler combustion of more than one third of total energy consumption. At present, the

15、 domestic most of the urban heating system in the operation of the boiler equipment aging basic rely on manual operation, automation level is low, safety performance is poor, the combustion efficiency is not high, the air pollution is very serious. Therefore, the configuration of automatic temperatu

16、re control system for boiler in todays increasingly serious environmentalpollution situation is extremely important.boiler temperature control based on PLC is introducedThis system is based on PLC boiler temperature control, through the boiler internal sensor for temperature and flow rate feedback t

17、o system parameters such as temperature control, the automatic control of boiler temperature is realized.PLC programmable controller is a kind of combined relay controller and computer, through the installer, central processing unit CPU as the core and I/O devices connected to its use in the field o

18、f industrial control computer is slightly different with ordinary computer, mainly by the CPU, memory cell, basic components such as the I/O interface circuit, power supply, plus extension, programmer, external equipment, etc. PLC programmable controller can not only replace the ordinary relay, but

19、also has A variety of extensions, such as A/D module, etc. Therefore, the use of PLC for automatic control of boiler provides a new solution, some advanced control method to the application.Using PLC programmable controller for boiler system, realize the automatic control of the temperature, on the

20、one hand can improve combustion efficiency, reduce fuel use and emissions of harmful gas in flue gas, reducing the air pollution; PLC control system, on the other hand, through a variety of sensors inside the boiler temperature, pressure, flow and other related parameters, realized the automatic con

21、trol of the parameters such as temperature. Reduces the manual labor, basically just in the engine room control room can fully understand the operation of the boiler, reduce the manpower cost, improve the level of the automation management system.the temperature control system designthe temperature

22、control system designThis design by Siemens S7-300 programmable controller for the next bit machine, two industrial control machine for PC. PC through industrial control software to realize early warning functions such as alarm, under a machine adopts Siemens S7-300 programmable controller, realize

23、automatic control, such as temperature, flow rate in the boiler control level and safety guaranteed.System for the temperature of the object, and using PT100 type thermal resistance sensors inside the boiler water temperature, and then passed to EM235 module temperature transmitter, convert the sign

24、al through the PID arithmetic, adjusted to get a stable PID parameter values, then the input signal to the silicon controlled voltage regulator to control the voltage of the heater, achieve the purpose of regulating temperature.the temperature control system hardware designthe host system. Using two

25、 sets of industrial control computer host, one of them as the main control machine, another one is complementary host, make double insurance. Configuration software WINCCSP26.0 using Siemens industrial control configuration software.PLC programmable controller. Systems use Siemens SP - 300 - PLC pro

26、grammable controller. Its modular structure, easy to implement distributed configuration and high cost performance, strong electromagnetic compatibility, resistance to shock impact performance is good, in a wide range of industrial control field, become a kind of economical and practical solution. V

27、ariety of increasing performance of CPU and rich with many convenient features I/O extension module (including SM signal module, communication processor CP, IM interface module, etc.). The user can choose according to actual application module.the instrument equipment. In order to improve the anti-i

28、nterference ability, type selection of instrument meter DDZ - IH 45 ma current output for 0123, to ensure the reliability of the system. Instrument include: flow transmitting, pressure transmitter, temperature transmitter, liquid level transmitter, micro oxygen transmitter, pressure transmitter, etc

29、.the frequency conversion control room. Mainly includes: power supply control cabinet, frequency conversion control cabinet, boiler circulating pump frequency conversion control cabinet, control cabinet is equipped with various types of relay contactor, relay, etc., low voltage electrical equipment

30、to complete the motor start and stop.the temperature control system software designPID instruction algorithmPID controller according to the error of the system parameter values, calculated by proportional integral and differential control quantity to control, so called, PID control and PID control.

31、In the field of industrial control, PID is still in wide use. Three kinds of control volume have different characteristics, separately to exist advantages and disadvantages are clearly, when used with various restrictions would have problems, how to adjust the PID parameter of the stability, becomes

32、 the current control of the most important step.characteristics of PID control algorithmthe proportion (P) control. Proportional (P) control is one of the most simple control method, the controller output to the input error signal is proportional to the relationship. Controller will happen if skewed

33、, adjust the control output, the accused to reduce the amount of deviation in the direction of change. Deviation reduce speed determined by proportional coefficient Kp, Kp the faster, the greater the deviation decrease. But this will cause oscillation, especially in the hysteresis link is larger, th

34、e proportional coefficient Kp reduce the possibility of oscillation will be reduced, but at the same time can also lead to slow adjustment. Proportional control weakness is cant eliminate the steady-state error, integral control must be available to assist.the integral (I) control. The output of the

35、 controller in the integral control is proportional to the input of the error signal integral relationship. After entering the steady state, if exist steady-state error control system, in order to eliminate the steady-state error of the system, the integral item must be added. As time increases, the

36、 integral term will also increase, so even the relatively small error integral item will also be increased with the increase of time, it will further reduce the steady state, the existence of error to zero. So the proportional integral (PI) controller can make the system enter the steady-state noste

37、ady-state error.differential (D) control. Under differential control, the controller output differential increases, the input error signal differential will also increase. The automatic control system for error control, there will be other unnecessary problems such as movements will more serious ins

38、tability. That is to say, in the controller only introduced ratio is often not enough. Proportional action is only magnified error amplitude, but join differential item to avoid large errors. Because it can predict the direction of the error change, but the differential control can enlarge the high

39、frequency noise, lower signal-to-noise ratio in the system, resulting in a decline in the ability of the system suppress interference. That is to say, differential control cant eliminate the residual.PID parameter settingPID parameters setting is mainly to adjust P Pi, Pt. To change the system chara

40、cteristic and causing the system to achieve satisfaction index.PID algorithm program implementationIn the SP - 300 - PID function is accomplished by PID instruction function block, by regularly perform PID function block. According to the PID operation rule, according to a given at the time, proport

41、ional integral differential data, calculate the control quantity.the PID program designSiemens PLC control program is to use the programming software S7V5. 3.First input analog signals, the boilers current voltage by numerical display. Second watch boiler the current temperature is normal, alarm ind

42、icator lamp whether can normal use. Initiator, observation after the start position, initialize the PID parameters, close the program, zero analog, continue to stop boiler heating but still shows the temperature. Set temperature, the interrupt program, adjust PID parameter, output PID arithmetic as

43、a result, the output analog signals.the configuration module designConfiguration software design. Select the configuration design of this system software is Siemens WINCC configuration software, WINCC is a powerful, has the very good open software. All kinds of complex task, WINCC can handle. WINCC

44、belongs to man-machine interface configuration tool, its biggest characteristic is to system integration on the basis of the configuration. As long as the preset of various software modules for simple configuration, you can easily implement each function of monitoring layer, shortens the time of system integration to improve the wor