外文翻译---一种基于DS18B20的温度探测系统

1、附录A Design of the Temperature Test System Basedon Grouping DS18B20AbstractAll the DS18B20 sensors, used for the multipoint test temperature, are connected with MCU on one of IO bus, and temperature data are collected by turns. If the system has a large amount of sensors, the time of MCU used in proc

2、essing the temperature data is obviously prolonged, so the cycle of alternate test gets longer. In this paper, a new method that DS18B20 are rationally grouped is presented, and some measures are taken in software; as a result, the speed of alternate test advances distinctly. Key words- DS18B20 Grou

3、p, temperature test, time spent on the alternate test.1. INTRODUCTION As the simple structure, convenient installment, low loss and wide range of temperature test, DS18B20 temperature test sensors are applied to the fields which need the multipoint temperature test, such as the chemical industry, th

4、e grain, the environment supervision and so on. Because of the adoption of one bus in the DS18B20 multipoint temperature test system, 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 must be read after reading-pin

5、 state for 8 times, and position and store data must be moved, so time spend much in reading one point of the data system by every time. If the temperature test system is large-scaled, the system loss caused by it is rather much, and then the alternate test speed of the system decreases obviously, w

6、hich influences the efficiency of the multipoint temperature test system seriously. In this paper, DS18B20 are hung on some I/O buses by grouping DS18B20 evenly, and the conversion temperature data is obtained by reading the state of DS18B20, then the system loss decreases and the alternate test spe

7、ed increases obviously, which wont influence the precision and the reliability of the conversion. A set of multipoint temperature test of artificial environment laboratory is achieved in this paper, which increases the test efficiency of the former system.2. CHARACTERISTICS OF DS18B20 DS18B20 is the

8、 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 (Device TH and TL).DS18B20 communicates with the microprocessor by the single bus port and

9、 the test range of DS18B20 is from -55 centigrade to +125 centigrade, and the incremental value is 0.5 centigrade. The temperature can be changed into figures within 720ms and each DS18B20 has the sole 64 figures serial number.Fig 1 DS18B20 64bit ROMThe specific content is revealed as Fig 1: There a

10、re two 8 figures storages (No.0 and No.1) for storing temperature value in DS18B20. No.0 storage stores complement of the temperature value, and No.1 stores symbols of the temperature value. The user can define non-volatile temperature alarms sets and distinguish the alarms search order and seek the

11、 component temperature alarms state outside the scheduled limit. There are two alternative ways of power supply: Signal bus high-level borrow power is adopted, or the +5v power supply externally is adopted directly.3. APPLICATION THE GROUPING TEST METHODThis paper illustrates the grouping method wit

12、h 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 of sensors cannot be divided by the number of buses even, the number disparity of senso

13、rs on buses is no more than one, which can be handled while reading numbers. The power is supplied externally. Owning to the synchronistic conversion in each DS18B20, the intense current is needed, and the signal bus cannot be used for the power supply, otherwise the system cannot work in order. The

14、 schematic circuit is shown as Fig 2 (the DS18B20 signal buses of the same group are hung on some buses of P1 port). When read and write the DS18B20, the strict schedule must be kept. First a reversion pulse is sent to all DS18B20. After the reversion, Skip ROM order is sent to each circuit simultan

15、eously from the I/O port, and the conversion order is sent, then all sensors begin transform. After the conversion, Match Rom order is sent to each circuit simultaneously, and 64 bits serial number is sent. DS18B20 is selected for each group, and Scratch Pad data is read. Finally the data is transfo

16、rmed. The data of serial-read is transformed into the actual temperature value. One alternate test is finished after the DS18B20 temperature data is read completely by the cyclical reading for 25 times.Fig 2 DS18B20 grouping sketch mapNow the time-consuming in the test system of the single bus and t

17、he grouping analyses method is illustrated respectively. The reversion time sequence and the time 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;

18、 the reading 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 test is calculated respectively as follows: (1) Single bus 495us+2*(8*60

19、+7)us+97.35ms+495us+100*(64*60+ 63+8*60+7+9*60+8)us=552.534ms (2) Grouping mode 495us+2*(8*60+7)us+97.35ms+20(64*60+63+8*60+7+9*60+8)us=189.804msAs the small proportion of the numeration system conversion and the storage time in the whole period, the unknown crystal-oscillator frequency, the numerat

20、ion system conversion and storage time is not counted. Accordingly, the alternate test time which grouping mode consumes is much shorter than single bus mode obviously.4. EXAMPLE OF THE DESIGNThe asphalt transportation vehicle is the main transportation equipment between the material field and road

21、surface. The unavoidable temperature decreasing because of the asphalt transportation vehicles 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 a set of wire

22、less temperature using DS18B20 grouping mode test system for testing the temperature of the asphalt transportation vehicle shell, and the total points is 120. Temperature test system software adopts the modular design. The hypogenous machine collects data, stores data, sets up DS18B20, and sends the

23、 wireless module and so on. The epigenous machine adopts PC machines, mainly receives the temperature data from the hypogenous machine. The epigenous machine displays, stores and manages data. The simple communication between people and machines is performed by the epigenous machine. This paper will

24、 not illustrate the simple procedure of the epigenous machine in detail. The following is the illustration of parts of hypogenous machine.A.System hardwareConsidering the multipoint temperature number of the temporary storage and the considerable internal RAM during the value conversion, the chief c

25、ontrolling chip adopts 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 OCMJ Jin Peng Company) and the keyboard module are added. The

26、 wireless digital transmission adopts the wireless module375 in the whole reception-sending form, which may has two amateur bands to choose and the regulative Baud Rate ( the max is 20Kbit/s), and the Single-Chip Microcomputer serial port data can be received directly. DS18B20, with the power supply

27、, 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 added to the system, the reversion signal is transmitted from the MAX813 reversion pin, and the value of the reversion pulse is

28、 200ms. When the procedure is in order, a pulse signal must be sent to MAX813 WDI pin in no more than the interval of 1.6s to clear away the watch-dog timer. If the interval is more than 1.6s, the pin does not receive the pulse signal, and then the 89C52 must be reversed. As 120 DS18B20 serial numbe

29、rs must be stored in the system, the data storage DS1225 (8K) against the power failure is developed.B.System software function and process The software part of the temperature test system numbers DS18B20, collects and transforms data, performs the wireless communication, manages keyboard and so on.

30、 For the convenience of the procedure debugging and the reliability, the module design is adopted, mainly including the keyboard processing module, the wireless communication module, the module of temperature collection and processing, the display module and so on. The chief procedure manages the ke

31、yboard, initializes the system and 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. First the wireless module is set up as the reception state to re

32、ceive 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 three logic is performed according to the bit).The wireless module is set up as the sleep state during the conversion and the transforming state durin

33、g the temperature data transmission. Packing sends the temperature data and the DS18B20 numbers in the system to epigenous machine. The parts of collection and conversion start the DS18B20 conversion, read the temperature data by grouping methods, store data and so on. The following procedure is the

34、 main content of collecting and conversion modules.5. CONCLUCTIONAuthors create the following new ideas:1. Alternate test time difference of the multipoint temperature test system in the grouping method and the single bus method is analyzed, then the alternate test speed can be increased greatly by

35、grouping method. 2.A set of wireless multipoint temperature test system is designed by DS18B20 grouping 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

36、achieved.一种基于DS18B20的温度探测系统摘要所有的DS18B20传感器，用于多点温度测试，IO总线与MCU连接，温度数据的轮流收集。如果系统有大量的传感器，MCU的时间用在处理温度数据明显延长，因此周期替代测试变得更长。在本文中，一种新的方法，DS18B20的合理组合和一些在软件上采取的措施，替代试验进展速度明显。关键词：DS18B20的集团，温度测试，轮流测试所花费的时间。引言由于结构简单，安装方便，低损失和广泛的用途的温度测试，DS18B20温度测试传感器应用领域，需要多点温度测试，如化学工业，粮食，环境监督管理等。因为通过一个DS18B20的多点温度测试系统总线，所有DS1

37、8B20是挂在一条总线上，然后每个温度测试点的值转换轮流读。作为转换后读值必须阅读8次引脚的状态，移动时间，位置和存储数据，所以时间多花费在阅读每一个点的数据系统时间。如果温度测试系统是大型系统由它造成的损失是相当多的，然后交替测试系统的运行速度明显降低，从而影响多点温度测试系统的效率。在本文中，DS18B20的一些I / O总线上都挂着分组DS18B20的均匀，温度转换获取数据读取DS18B20的状态， 系统损耗减少和替代测试速度增加显然，这将不会影响精度和转换的可靠性。一套点对多点温度，在此实现人工环境实验室测试，这增加了测试效率。作者对DS18B20的认识DS18B20是单总线数字温度传

38、感器来自美国达拉斯公司。 DS18B20是由64数字光盘刻激光，温度敏感性组成部分，非易失性温度报警触发器（设备TH和TL）。DS18B20的通信微处理器单总线端口和测试范围DS18B20是从-55摄氏度到+125摄氏度，增量值是0.5摄氏度。温度可在720ms的数字改为每个DS18B20具有唯一的64数字序号。图1揭示的具体内容：两个8的数字储量（0号和1号），用于存储在DS18B20的温度值。0号存储存储器温度值，补充和一号存储器温度值的符号。用户可以定义非挥发的温度报警台和区分报警搜索命令，并寻求组件温度预定限额以外的报警状态。有两个电源的替代方法：信号总线的高级别借采用电源或+5V外部

39、电源直接采用。图1 DS18B20的64位ROM应用程序的分组试验方法本文阐述了DS18B20与89C52接口的分组方法。假设量P1口的总线是和温度测试系统需要100 DS18B20的传感器，可以平均分配4 I / O线。如果传感器的数量不能分割由总线数目甚至，传感器的数量差距总线上是不超过一个，它可以处理，而阅读数字。外部供电电源。拥有在每个DS18B20的同时性的转换，激烈当前是必要的，不能使用和信号总线电源，否则系统无法工作秩序。 “电路原理图2所示（DS18B20的信号同组的公共汽车上都挂着P1口的一些公共汽车）。当读写DS18B20的，严格的时间表被保留。首先回归脉冲被发送到所有DS

40、18B20的。后回归，跳过ROM命令发送到每个电路同时的I / O端口，转换顺序发送的，那么所有的传感器开始转变。转换后，匹配ROM命令同时发送到每个电路，64位序列号发送。 DS18B20是每个选择组，便签数据读取。最后的数据是转化。串行读取数据转化为实际温度值。一名候补测试完成后DS18B20温度数据读取完全由周期性的读数为25倍。 图2 DS18B20的分组示意图现在，在单总线和分组分析法测试系统耗时分别说明。回归时间序列和时间序列的写作和阅读的一个位微处理器在数字4-6中显示。DS18B20的回归周期为495us，1020us;一位写作时间是60us-120us;一位读期间以上60us;写入或读取下位跨度是微秒。由于A / D转换时间为97.35ms（9精密度），如果它是由最短的方法计算，替代测试总耗时分别计算如下：单总线：495us+2*(8*60+7)us+97.35ms+495us+100*(64*60+63+8*60+7+9*