溫室溫度監(jiān)控系統(tǒng)設(shè)計(jì)

電氣自動(dòng)化論文編號(hào):ZD956    論文字?jǐn)?shù):13513,頁數(shù):36 
 
目  錄
摘  要 I
Abstract II
第1章  緒論 1
1.1選題的背景及意義 1
1.2課題研究的主要內(nèi)容 1
第2章  系統(tǒng)方案設(shè)計(jì) 2
2. 1系統(tǒng)實(shí)現(xiàn)方案的比較 2
2. 1.1傳統(tǒng)方案 2
 2. 1.2本設(shè)計(jì)的方案 2
2.2溫度傳感器的選擇 3
2.2.1 DS18B20簡(jiǎn)介 4
2.2.2 DS18B20的性能特點(diǎn) 5
2.2.3 DS18B20的管腳排列 5
2.2.3 DS18B20的內(nèi)部結(jié)構(gòu) 6
2.2.3 DS18B20的控制方法 9
2.2.3 DS18B20的測(cè)溫原理 10
2.3單片機(jī)的選擇 11
2.3.1單片機(jī)概述 11
2.3.2 AT89S51芯片的主要性能 12
2.3.3 AT89C2051芯片的主要性能 12
2.3.4 AT89C2051芯片的管腳說明 13
2.4 串行通信 15
2.4.1 串行接口標(biāo)準(zhǔn) 15
2.4.2 RS-485的特點(diǎn) 17
第3章  系統(tǒng)硬件電路設(shè)計(jì) 19
3.1 下位機(jī)電路設(shè)計(jì) 19
3.1.1溫度采集電路 20
3.1.2 輸出控制電路 20
3.2上位機(jī)電路設(shè)計(jì) 20
3.2.1鍵盤電路 21
3.2.2顯示電路 21
第4章  系統(tǒng)軟件的設(shè)計(jì) 23
4.1系統(tǒng)主程序 23
 4.1.1 下位機(jī)程序 23
 4.1.2 上位機(jī)程序 24
4.2系統(tǒng)部分程序 24
 4.2.1 DS18B20初始化子程序 25
 4.2.2 DS18B20讀子程序 26
 4.2.3 DS18B20寫子程序 27
 4.2.4 DS18B20定時(shí)顯示子程序 28
 4.2.5 DS18B20溫度轉(zhuǎn)換子程序 29
第5章  課題的總結(jié) 30
致謝 31
主要參考文獻(xiàn)： 32

摘  要

 隨著溫室技術(shù)的普及，溫室數(shù)量不斷增多，溫室的溫度控制成為一個(gè)難題。目前應(yīng)用于溫室的溫度檢測(cè)系統(tǒng)大多采用由模擬溫度傳感器、多路模擬開關(guān)、AD轉(zhuǎn)換器及單片機(jī)等組成的傳輸系統(tǒng)。這種溫度采集系統(tǒng)需要在溫室內(nèi)布置大量的測(cè)溫電纜，才能把現(xiàn)場(chǎng)傳感器的信號(hào)送到采集卡上，安裝和拆卸繁雜，成本也高。同時(shí)線路上傳送的是模擬信號(hào)，易受干擾和損耗，測(cè)量誤差也比較大，不利于控制者根據(jù)溫度變化及時(shí)做出決定。在這樣的形式下，開發(fā)一種實(shí)時(shí)性高、精度高，能夠綜合處理多點(diǎn)溫度信息的測(cè)控系統(tǒng)就很有必要。
 本課題提出一種基于單片機(jī)的總線結(jié)構(gòu)溫度測(cè)控系統(tǒng)應(yīng)用于溫室的的設(shè)計(jì)方案，該方案是利用溫度傳感器將溫室內(nèi)溫度的變化，變換成電流的變化，再轉(zhuǎn)換為電壓變化輸入模數(shù)轉(zhuǎn)換器，其值由單片機(jī)處理，最后由單片機(jī)去控制數(shù)字顯示器，顯示溫室內(nèi)的實(shí)際溫度。一旦該溫度值超過我們預(yù)先設(shè)定的上、下限，單片機(jī)便啟動(dòng)控制裝置，進(jìn)而對(duì)溫室內(nèi)溫度進(jìn)行控制。為了能夠多通道數(shù)據(jù)采集和處理，系統(tǒng)采用了一臺(tái)上位機(jī)和多個(gè)下位機(jī)的集總式結(jié)構(gòu)。上位機(jī)采用AT89S51單片機(jī)，下位機(jī)采用AT89C2051單片機(jī)。上位機(jī)與下位機(jī)之問采用RS485總線通信。其中上位機(jī)系統(tǒng)配置液晶顯示屏、按鍵。該測(cè)控系統(tǒng)安裝簡(jiǎn)單方便，系統(tǒng)穩(wěn)定可靠、可維護(hù)性好。
關(guān)鍵詞: 單片機(jī); RS485總線; 溫度傳感器; 溫度監(jiān)控; 溫室

 Abstract

 With the popularity of greenhouse technology, the amount of greenhouse is larger and lager. However, the temperature control of greenhouse is becoming a difficult problem. Currently,the  temperature control system of greenhouse is mostly using a transfers system which consists of analog temperature sensor, multiplexing analog switches, AD conversion units and SCM. This kind of temperature collection system needs a lot of cables which is laid to make the single of the sensor be sent to the collection card in the greenhouse.Thus the work of fixing and take-down is miscellaneous,and the cost is high.What’s more,the transmission line is analog signal which are vulnerable to interference and loss, measurement error is relatively large, were not conducive to control temperature in a timely manner according to a decision. In this form, to develop a real-time, high precision, integrated approach to multi-point temperature measurement and control information system will be necessary.     This issue gives a temperature control of greenhouse based on SCM and digital monobus technology. In this project，the change of temperature in the greenhouse is transformed into the change of electric current and  then into the change of  voltage by using the temperature sensors.The change of voltage is input inio the AD conversion units and the result is dealt with by SCM.At last the realtime temperature in the greenhouse is displayed on the monitor under the control of SCM.Once the value of the temperature in the greenhouse exceeds the minimum and maximum whieh is preestablished.SCM will start the control device, and thus to control the temperature inside the greenhouse. To be able to the multi-channel data acquisition and processing ,system is a mian machine and a number of lower machines structure. Main machine is AT89S51 , lower machine is AT89C2051. they communicate with each other by RS485 bus. And the main machine deploy LCD, keys. The control system easy to install, system is reliable and good maintainability.