基于ds18b20分組方式測(cè)溫系統(tǒng)設(shè)計(jì)外文翻譯

1、<p>　　學(xué)校代碼：11517</p><p>　　學(xué) 號(hào)：201050712216</p><p>　　HENAN INSTITUTE OF ENGINEERING</p><p><b>　　文獻(xiàn)翻譯</b></p><p>　　題 目 電子萬年歷的設(shè)計(jì)與實(shí)現(xiàn) </p>

2、<p>　　學(xué)生姓名 姚 俊 霞 </p><p>　　專業(yè)班級(jí) 電氣工程及其自動(dòng)化 </p><p>　　學(xué) 號(hào) 201050712216 </p><p>　　系 （部） 電氣信息工程系 </p><p>　　指導(dǎo)教師(職稱

3、) 李 娜（講師） </p><p>　　完成時(shí)間 2012年2月17日 </p><p>　　基于DS18B20分組方式測(cè)溫系統(tǒng)設(shè)計(jì)</p><p>　　LI Ping ZHOU Yucai Xiangjun ZENG YANG Ting-fang</p><p>　　Changsha University

4、 of Science and Technology,</p><p>　　Changsha 410077, Hunan, P. R. China.</p><p>　　摘 要：當(dāng)用于多點(diǎn)測(cè)溫時(shí)，所有的DS18B20傳感器都連接在單片機(jī)的某根總線上，采用輪流采集溫度數(shù)據(jù)的方式。當(dāng)系統(tǒng)有多個(gè)傳感器時(shí)，單片機(jī)用于處理溫度數(shù)據(jù)的時(shí)間就會(huì)明顯延長，從而導(dǎo)致測(cè)溫系統(tǒng)周期增長。在本文中，采取對(duì)DS1

5、8B20合理的分組的方法，并在軟件上采取一定措施，從而明顯的提高交替檢測(cè)速度。</p><p>　　關(guān)鍵詞：DS18B20分組/溫度測(cè)試/交替檢測(cè)時(shí)間</p><p><b>　　1 引言</b></p><p>　　DS18B20溫度傳感器由于其結(jié)構(gòu)簡(jiǎn)單、安裝方便、低損耗以及測(cè)溫范圍寬而被廣泛應(yīng)用于需要多點(diǎn)測(cè)溫的地方，像化工，糧食，環(huán)境監(jiān)測(cè)等

6、等。由于多點(diǎn)溫度測(cè)試系統(tǒng)采用的是單總線方式，所有的DS18B20傳感器掛在一根總線上，然后輪流讀取每一個(gè)測(cè)試點(diǎn)的溫度轉(zhuǎn)換值。由于讀取單個(gè)傳感器的轉(zhuǎn)換值需要讀8次管腳狀態(tài)，并要進(jìn)行移位存儲(chǔ)數(shù)據(jù)，所以系統(tǒng)讀取每一點(diǎn)的數(shù)據(jù)花費(fèi)的時(shí)間不小，如果測(cè)溫系統(tǒng)規(guī)模較大的話，由此造成的系統(tǒng)損耗也是相當(dāng)大的。從而導(dǎo)致系統(tǒng)的交替檢測(cè)速度明顯下降，極大的影響了多點(diǎn)測(cè)溫系統(tǒng)的檢測(cè)效率。本文中，對(duì)DS18B20平均分組并掛到多根I/O線上，通過同時(shí)讀取DS18B2

7、0的狀態(tài)得到轉(zhuǎn)換的溫度數(shù)據(jù)，從而明顯提高交替檢測(cè)速度并降低系統(tǒng)開銷，同時(shí)又不影響轉(zhuǎn)換精度及可靠性。本文實(shí)現(xiàn)了一套人工環(huán)境實(shí)驗(yàn)室的多點(diǎn)溫度測(cè)試，明顯提高了原有測(cè)試系統(tǒng)的檢測(cè)效率。</p><p>　　2 DS18B20的特性</p><p>　　DS18B20是由美國Dallas公司設(shè)計(jì)的單線數(shù)字溫度傳感器．它由64位激光刻印ROM、溫敏元件、非易失性溫度報(bào)警觸發(fā)器TH和TL器件三個(gè)部分組成

8、，其與單片機(jī)的通信采用單線接口，DS18B20的測(cè)量范圍是-55℃到+125℃，增量值為0.5℃。溫度變換為數(shù)字可在720ms內(nèi)完成，每一個(gè)DS18B20具有唯一的64位的序列號(hào)（圖1），DS18B20內(nèi)部有兩個(gè)8位存儲(chǔ)器RAM用來儲(chǔ)存溫度值（0號(hào)和1號(hào)），其中0號(hào)存儲(chǔ)器存放溫度值的補(bǔ)碼，1號(hào)存儲(chǔ)器存儲(chǔ)溫度值的符號(hào)。用戶可以定義非易失性的溫度告警設(shè)置并且區(qū)分告警搜索命令，尋求組件溫度警報(bào)狀態(tài)以外的預(yù)定的限制。有兩種供電方式：利用信號(hào)線高

9、電平時(shí)借電供電，或直接用+5V電源。</p><p>　　圖1 DS18B2064為ROM</p><p>　　3 應(yīng)用分組測(cè)試方法</p><p>　　本文以DS18B20與89C52的接口說明分組測(cè)試方法，假定P1口上的總線數(shù)為4，溫度測(cè)試系統(tǒng)需要100個(gè)DS18B20傳感器，可將100個(gè)傳感器平均分配到4根I/O線上，如果傳感器數(shù)量不能被總線數(shù)整除，可使連在

10、總線上的傳感器數(shù)量差別不超過1個(gè)，這樣讀數(shù)時(shí)就能解決。電源采取外部供電，由于每個(gè)DS18B20都是同步轉(zhuǎn)換，所以需要較強(qiáng)電流，不能用信號(hào)線供電，否則系統(tǒng)無法正常工作。 線路連接如圖2示（同組的DS18B20信號(hào)線都連接在P1口的一根總線上）。當(dāng)對(duì)DS18B20進(jìn)行讀寫時(shí)，必須嚴(yán)格保持時(shí)序要求。首先給所有的DS18B20發(fā)一個(gè)復(fù)位脈沖，復(fù)位后，從各I/O口發(fā)送跳轉(zhuǎn)ROM命令，轉(zhuǎn)換以后，向各路同時(shí)發(fā)匹配ROM命令，接著發(fā)送64位序列號(hào)，每組

11、選擇一個(gè)DS18B20，讀取Scratch Pad 數(shù)據(jù)，最后進(jìn)行數(shù)據(jù)轉(zhuǎn)換，將串行讀取的數(shù)據(jù)轉(zhuǎn)換成實(shí)際值，循環(huán)讀取25次將所有DSl8820溫度數(shù)據(jù)完全讀完，一次交替測(cè)試完成，整個(gè)流程如圖3所示。</p><p>　　圖2 DS18B20連線圖</p><p>　　圖3 DS18B20分組方式溫度采集流程</p><p>　　現(xiàn)在來分析單總線方式和分組方式測(cè)試

12、系統(tǒng)耗時(shí)，圖4、圖5、圖6分別為DSl8B20的復(fù)位時(shí)序、單片機(jī)寫一位和讀一位的時(shí)序。DS18B20的復(fù)位時(shí)間為495us一1020us，寫一位時(shí)間為60us一120us，讀一位時(shí)間為60us以上，讀寫相臨一位時(shí)間間隔為1us。因?yàn)锳/D轉(zhuǎn)換時(shí)間為97.35ms（9位精度）,如果按最短時(shí)間計(jì)算，整個(gè)交替檢測(cè)時(shí)間分別為：</p><p><b>　　(1)單總線</b></p>

13、<p>　　495us+2*(8*60+7)us+97.35ms+495us+100*(64*60+63+8*60+7+9*60+8)us=552.534ms (3-1)</p><p><b>　　(2)分組模式</b></p><p>

14、　　495us+2*(8*60+7)us+97.35ms+20(64*60+63+8*60+7+9*60+8)us=189.804ms (3-2)</p><p>　　因?yàn)閿?shù)制轉(zhuǎn)換和存儲(chǔ)時(shí)間占整個(gè)交替檢測(cè)時(shí)間很小，以及無法確定晶振頻率，這里就不計(jì)算數(shù)制轉(zhuǎn)換和存儲(chǔ)時(shí)間。因此，分組模式所用時(shí)間明顯少于單總線模式。</p><p>　　圖4 DS18B20時(shí)間序列</p><

15、;p>　　圖5 DS18B20寫時(shí)序</p><p>　　圖6 DS18B20讀時(shí)序</p><p><b>　　4 設(shè)計(jì)實(shí)例</b></p><p>　　瀝青運(yùn)輸車是用于原料場(chǎng)和路面之間的主要輸送設(shè)備，。由于瀝青轉(zhuǎn)運(yùn)車在高寒地區(qū)作業(yè)或運(yùn)送距離過長時(shí)不可避免的產(chǎn)生溫降，這會(huì)影響路面的攤鋪質(zhì)量，所以必須根據(jù)外殼的散熱情況采取具體的保溫措

16、施。本文設(shè)計(jì)了一套用于瀝青運(yùn)輸車外殼溫度分布的無線溫度測(cè)試系統(tǒng)基于DS18B20分組方式，總共120個(gè)點(diǎn)。溫度測(cè)試系統(tǒng)采用主從方式，下位機(jī)負(fù)責(zé)采集數(shù)據(jù)，存儲(chǔ)數(shù)據(jù)，設(shè)置傳感器，無線傳輸?shù)?。上位機(jī)采用PC機(jī)，主要負(fù)責(zé)接收下位機(jī)發(fā)送過來的溫度數(shù)據(jù)，并進(jìn)行顯示，存儲(chǔ)等數(shù)據(jù)管理工作以及簡(jiǎn)單的人機(jī)交互。</p><p><b>　　4.1 系統(tǒng)硬件</b></p><p>　　考

17、慮到主控芯片需存儲(chǔ)多點(diǎn)的溫度值并進(jìn)行數(shù)值轉(zhuǎn)換，需要較多內(nèi)部RAM，因此采用ATMEL公司89C52單片機(jī)，其帶有256字節(jié)RAM和8KB E2PROM程序存儲(chǔ)器。因?yàn)橐獙?duì)DS18B20的序列號(hào)進(jìn)行區(qū)分和編碼，所以增加了液晶模塊和鍵盤模塊,無線數(shù)傳部分則選用收發(fā)一體式無線模塊PTR2000，該模塊可以有兩個(gè)業(yè)余頻段選擇(433.9MHd434.33MHz)，波特率可調(diào)(最高可達(dá)20Kbit/s），可以直接接收單片機(jī)串I:I收據(jù)。系統(tǒng)硬件結(jié)

18、構(gòu)具體如下圖所示，DSl8820采用電源供電方式，共分8組分別掛在P1 El(P1.0-P1.7)，無線模塊則直接掛在串口上，硬件看門狗采用MAX813芯片．當(dāng)系統(tǒng)加電時(shí)，89C52的復(fù)位信號(hào)由MAX813的復(fù)位管腳輸出，復(fù)位脈沖的值為200 ms。程序正常運(yùn)行時(shí)，必須在小于1.6s的時(shí)間間隔內(nèi)向MAX813的WDI管腳發(fā)送一個(gè)脈沖信號(hào)，以清除芯片內(nèi)部看門狗定時(shí)器。若超過1.6s該管腳都沒收到脈沖信號(hào)，則使89C52復(fù)位?？紤]到系統(tǒng)須存

19、取120個(gè)DSl8820的序列號(hào)。所以擴(kuò)展了一片8K帶掉電保護(hù)功能的數(shù)據(jù)存取器DSl225。</p><p><b>　　圖7 系統(tǒng)硬件框圖</b></p><p>　　4.2 系統(tǒng)軟件功能和流程</p><p>　　溫度測(cè)試系統(tǒng)軟件部分，負(fù)責(zé)完成對(duì)DSl8820的編號(hào)、數(shù)據(jù)采集及轉(zhuǎn)換、無線通訊及鍵盤管理等，為了調(diào)試程序方便，提高可靠性，采用了

20、模塊化設(shè)計(jì)，主要有鍵盤處理模塊、無線通訊模塊、溫度采集和處理模塊、顯示模塊等，軟件流程具體如圖8所示。加電源復(fù)位后，89C52首先自檢，當(dāng)自檢結(jié)束后調(diào)用各子程序模塊。主程序負(fù)責(zé)鍵盤管理、系統(tǒng)初始化及各功能模塊的調(diào)用。系統(tǒng)中留有口線以實(shí)現(xiàn)DSl8820的編程任務(wù)。利用鍵盤和顯示配合讀取120點(diǎn)DS18B20的序列號(hào)，之后編號(hào)存入DS1225Y中，一開始無線模塊設(shè)置為接收狀態(tài)，以接收采集數(shù)據(jù)啟動(dòng)命令，轉(zhuǎn)換時(shí)，無無線模塊設(shè)置為休眠狀態(tài)，在進(jìn)行

21、溫度數(shù)據(jù)上傳時(shí)模塊設(shè)置為發(fā)送狀態(tài)，將溫度數(shù)據(jù)和DS18B20的系統(tǒng)編號(hào)發(fā)送給上位機(jī)。</p><p>　　圖8 系統(tǒng)軟件流程圖</p><p>　　采集和轉(zhuǎn)換部分啟動(dòng)DS18B20轉(zhuǎn)換，分組方式讀取溫度數(shù)據(jù)，存儲(chǔ)數(shù)據(jù)等等。以下程序?yàn)椴杉?，轉(zhuǎn)換模塊的主要內(nèi)容：</p><p>　　void Get_ Temperature(void)</p><p

22、>　　{ uchar i,j , temp_ lsb, temp_ msb;</p><p>　　for(i=0;i<8;i++)</p><p>　　{skip_rom(i);//跳過序列號(hào)檢驗(yàn)</p><p>　　write_bytes(0x44 );}</p><p>　　//各路同時(shí)開始溫度轉(zhuǎn)換</p>&l

23、t;p>　　for(j=0;j<100;j++)</p><p>　　//延時(shí)0.1s，等待轉(zhuǎn)換結(jié)束</p><p>　　{delay(1000);}</p><p>　　For(j=0;j<15;j++)</p><p>　　{ match_ rom(j); read_ scratchpads (j); }</p&g

24、t;<p>　　for(j=0;j<120;j++)</p><p>　　{temp_lsb = temp_pad[j][0] ;</p><p>　　//溫度值的數(shù)據(jù)轉(zhuǎn)換</p><p>　　temp_msb = temp_pad[j][1] ;</p><p>　　temp_lsb >>= 4 ; temp

25、_msb <<= 4 ;</p><p>　　temp_lsb |=temp_msb; temp_msb = (temp_lsb/10) ;</p><p>　　temp_msb <<=4 ; temp_lsb %= 10 ;</p><p>　　temp_lsb |=temp_msb; temperature_ vel[j] =</p

26、><p>　　temp_lsb;}}</p><p><b>　　5 結(jié)論</b></p><p><b>　　本文作者創(chuàng)新點(diǎn)：</b></p><p>　　1) 通過分析基于單總線方式和分組方式的多點(diǎn)溫度測(cè)試系統(tǒng)的交替檢測(cè)時(shí)間的差別，得出分組方式能明顯提高交替檢測(cè)速度；</p><

27、p>　　2) 設(shè)計(jì)了一套基于DS18B20分組方式的無線多點(diǎn)溫度測(cè)試系統(tǒng)，這套系統(tǒng)已經(jīng)用于一家大型機(jī)械公司的瀝青運(yùn)輸車的技術(shù)改造中，并取得良好的效果。</p><p><b>　　參考文獻(xiàn)</b></p><p>　　[1] ShenJin,SongJingLing. An All-digital Temperature Measuring System Us

28、ed in Grain Barns.Transaction of the chese society for Agricultural Machinery,2001,(2):89 91.</p><p>　　[2] LiMinHui,Jung Deqiong. A Device of Temperature Measuremen Made up of DS1820 and AT89C205. Journal of

29、 Sichan Normal University 1997,(5):93-96</p><p>　　[3] Qi ZhiCai,Gai Shuang. Embedded Control System of the CentralAir conditioner Room,InstrumentTechnique and Sensor 2002,(5):25-26.</p><p>　　[4]

30、 ZhangPeiren,ZhouYanping. A Large-Scale Temperature Alarm System Based on 1 Wire Bus and CAN bus, Control&Automation 2003,(2):25-26</p><p><b>　　（英文原文）</b></p><p>　　A Design of th

31、e Temperature Test System </p><p>　　Based on Grouping DS18B20</p><p>　　LI Ping ZHOU Yucai Xiangjun ZENG YANG Ting-fang</p><p>　　Changsha University of Science and Technology,</p&

32、gt;<p>　　Changsha 410077, Hunan, P. R. China.</p><p>　　Abstract- All the DS18B20 sensors, used for the multipoint test temperature, are connected with MCU on one of IO bus, and temperature data are co

33、llected by turns. If the system has a large amount of sensors, the time of MCU used in processing the temperature data is obviously prolonged, so the cycle of alternate test gets longer. In this paper, a new method that

34、DS18B20 are rationally grouped is presented, and some measures are taken in software; as a result, the speed of alternate test advances</p><p>　　Key words- DS18B20 Group ,temperature test, time spent on the

35、alternate test.</p><p>　　I. INTRODUCTION</p><p>　　As the simple structure, convenient installment, low loss and wide range of temperature test, DS18B20 temperature test sensors are applied to th

36、e fields which need the multipoint temperature test, such as the chemical industry, the grain, the environment supervision and so on. Because of the adoption of one bus in the DS18B20 multipoint temperature test system,

37、all DS18B20 are hung on one bus, and then the temperature conversion value of each test point is read by turns. As the conversion value </p><p>　?、? CHARACTERISTICS OF DS18B20</p><p>　　DS18B20 i

38、s the single bus digital temperature sensor from American Dallas Company. DS18B20 is consisted of the 64 figures ROM engraved by laser, the temperature sensitivity component, non-volatile temperature alarms trigger (Devi

39、ce TH and TL).DS18B20 communicates with the microprocessor by the single bus port and the test range of DS18B20 is from -55 centigrade to +125 centigrade, and the incremental value is 0.5 centigrade. The temperature can

40、be changed into figures within 720ms and each DS18B</p><p>　　Fig 1 DS18B20 64bit ROM</p><p>　?、? APPLICATION THE GROUPING TEST METHOD</p><p>　　This paper illustrates the grouping me

41、thod with the interface of DS18B20 and 89C52. Assuming the amount of the buses on P1 port is 4 and the temperature test system needs 100 DS18B20 sensors, which can be distributed equally to the 4 I/O lines. If the number

42、 of sensors cannot be divided by the number of buses even, the number disparity of sensorson buses is no more than one, which can be handled while reading numbers. The power is supplied externally. Owning to the synchron

43、istic conversion in ea</p><p>　　Now the time-consuming in the test system of the single bus and the grouping analyses method is illustrated respectively. The reversion time sequence and the time</p>&

44、lt;p>　　sequence of writing and reading one bit for the microprocessor are revealed in figures 4-6. The figure show: The reversion period of DS18B20 is 495us-1020us;the writing period of one bit is 60us-120us;the readi

45、ng period of one bit is above 60us; the span of writing or reading the next bit is 1us. As the A/D conversion time is 97.35ms (9 precisions), if it is counted by the shortest way, the total time-consuming of alternate te

46、st is calculated respectively as follows:</p><p>　　(1) Single bus</p><p>　　495us+2*(8*60+7)us+97.35ms+495us+100*(64*60+63+8*60+7+9*60+8)us=552.534ms</p><p>　　(2) Grouping mode</p

47、><p>　　495us+2*(8*60+7)us+97.35ms+20(64*60+63+8*60+7+9*60+8)us=189.804ms</p><p>　　Fig 3 the diagram of collecting temperature by grouped DS18B20</p><p>　　As the small proportion of th

48、e numeration system conversion and the storage time in the whole period, the unknown crystal-oscillator frequency, the numeration system</p><p>　　conversion and storage time is not counted. Accordingly, the

49、alternate test time which grouping mode consumes is much shorter than single bus mode obviously</p><p>　　Fig 4 DS18B20 reversion time sequenceFig 4 DS18B20 reversion time sequence</p><p>　　IV.

50、EXAMPLE OF THE DESIGN</p><p>　　The asphalt transportation vehicle is the main transportation equipment between the material field and road surface. The unavoidable temperature decreasing because of the aspha

51、lt transportation vehicle’s long working and transportation distance influences the paving quality of the road surface, the specific measures must be taken according to the heat release of the shell. This paper designed

52、a set of wireless temperature using DS18B20 grouping mode test system for testing the temperature of the</p><p>　　machine. including the components of system hardware , software functions and process.</p&

53、gt;<p>　　A. System hardware</p><p>　　Considering the multipoint temperature number of the temporary storage and the considerable internal RAM during the value conversion, the chief controlling chip ad

54、opts ATMEL 89C52 Single-Chip Microcomputer with 256 bytes RAM and 8KB E2PROM procedure storage. As the distinguishable code of DS18S20 is read and numbered, the liquid crystal module (Ao Kela Chinese integrated module of

55、</p><p>　　OCMJ Jin Peng Company) and the keyboard module are added. The wireless digital transmission adopts the wireless module PTR2000 in the whole reception-sending form, which may has two amateur bands

56、to choose and the regulative Baud</p><p>　　Rate ( the max is 20Kbit/s), and the Single-Chip Microcomputer serial port data can be received directly. The system hardware structure is shown as Fig 7:</p>

57、<p>　　DS18B20, with the power supply, divided into 8 groups hung on P1 port (P1.0-P1.7). The wireless module is hung on serial port directly and the hardware watchdog adopts the MAX813 chip. When the power is adde

58、d to the system, the 89C52 reversion signal is transmitted from the MAX813 reversion pin, and the value of the reversion pulse is 200ms. When the procedure is in order, a pulse signal must be sent to MAX813 WDI pin in no

59、 more than the interval of 1.6s to clear away the watch-dog timer. If the</p><p>　　B. System software function and process</p><p>　　The software part of the temperature test system numbers DS18B

60、20, collects and transforms data, performs the wireless communication, manages keyboard and so on. For the convenience of the procedure debugging and the reliability, the module design is adopted, mainly including the ke

61、yboard processing module, the wireless communication module, the module of temperature collection and processing, the display module and so on. The software flow chart is shown as Fig 8 After the reversion of add power&l

62、t;/p><p>　　transfers each functional module. The haul line is kept to perform DS18B20 edit mission. 120 points serial number of DS18B20 is read by the keyboard and display coordination and numbered into DS1225Y

63、. First the wireless module is set up as the reception state to receive the collection parameters and start the order (The transmission content is sent by pack ; the same content is sent for three times ; two out of thre

64、e logic is performed according to the bit).</p><p>　　The wireless module is set up as the sleep state during the conversion and the transforming state during the temperature data transmission. Packing sends

65、the temperature data and the DS18B20 numbers in the system to epigenous machine. The</p><p>　　parts of collection and conversion start the DS18B20 conversion, read the temperature data by grouping methods, s

66、tore data and so on. The following procedure is the main</p><p>　　content of collecting and conversion modules:</p><p>　　void Get_ Temperature(void)</p><p>　　{ uchar i,j , temp_ lsb

67、, temp_ msb;</p><p>　　for(i=0;i<8;i++)</p><p>　　{skip_rom(i);//skip over the serial numbers to check</p><p>　　write_bytes(0x44 );}</p><p>　　//transform the temperatu

68、re in each circuit at the same time</p><p>　　for(j=0;j<100;j++)</p><p>　　// prolong the time for 0.1s; wait for the end of conversion</p><p>　　{delay(1000);}</p><p>

69、　　For(j=0;j<15;j++)</p><p>　　{ match_ rom(j); read_ scratchpads (j); }</p><p>　　//each temperature value is read in 8 buses</p><p>　　for(j=0;j<120;j++)</p><p>　　{

70、temp_lsb = temp_pad[j][0] ;</p><p>　　//the data conversion of the temperature value</p><p>　　temp_msb = temp_pad[j][1] ;</p><p>　　temp_lsb >>= 4 ; temp_msb <<= 4 ;</p

71、><p>　　temp_lsb |=temp_msb; temp_msb = (temp_lsb/10) ;</p><p>　　temp_msb <<=4 ; temp_lsb %= 10 ;</p><p>　　temp_lsb |=temp_msb; temperature_ vel[j] =</p><p>　　temp_ls

72、b;}}</p><p>　　V. CONCLUSION </p><p>　　Authors create the following new ideas</p><p>　　1）Alternate test time difference of the multipoint temperature test system in the grouping meth

73、od and the single bus method is analyzed, then the alternate test speed can be increased greatly by grouping method.</p><p>　　2）A set of wireless multipoint temperature test system is designed by DS18B20 gro

74、uping method. This system is applied to the technology reform of the asphalt transportation vehicle in some domestic large-scale engineering mechanical company and the good result of the application is achieved.</p>

75、;<p>　　REFERENCES</p><p>　　[1] ShenJin,SongJingLing. An All-digital Temperature Measuring System Used in Grain Barns.Transaction of the chese society for Agricultural Machinery,2001,(2):89 91.</p&g

76、t;<p>　　[2] LiMinHui,Jung Deqiong. A Device of Temperature Measuremen Made up of DS1820 and AT89C205. Journal of Sichan Normal University 1997,(5):93-96</p><p>　　[3] Qi ZhiCai,Gai Shuang. Embedded Con

77、trol System of the CentralAir conditioner Room,InstrumentTechnique and Sensor 2002,(5):25-26.</p><p>　　[4] ZhangPeiren,ZhouYanping. A Large-Scale Temperature Alarm System Based on 1 Wire Bus and CAN bus, Con