基于DS18B20的啤酒发酵温度测控系统 毕业设计外文资料翻译.doc

毕业设计外文资料翻译题 目 基于ds18b20的啤酒发酵 温度测控系统 学 院 自动化与电气工程学院 专 业 自动化 班 级 自动化xxxx班 学 生 xxxxxxxxx 学 号 20100321166 指导教师 xxxxx 二一四年三月三十一日- 12 -advanced materials research vols. 108-111 (2010) pp 898-902 (2010) trans tech publications, switzerlanddoi:10.4028//amr.108-111.898temperature detecting system of beer fermentationbased on ds18b20fen-ping zhou, hong-tao ma, bing-dong sui，and jia-mo suncollege of information science & engineering, hebei university of science and technologyhebei, shijiazhuang 050054, c,,keywords: ds18b20, temperature detecting, beer fermentation, bus-driving, fault detecting abstract. this paper introduces a temperature detection system in beer fermentation. a temperature monitoring system with characteristics of bus topology structure is composed of industrial computer, temperature detector, bus converter, transmission bus and especially 1-wire digital temperature sensor ds18b20. four-core cable is used to form a tree-like or star-like network, in which 54 digital temperature sensors existing on 18 fermentation tanks can be connected.the quantity of junction wires between temperature sensor and computer will be reduced greatly.temperature detector provides power supply for bus converter and ds18b20 through four-core cable. because bus converter has used hardware fault detecting technology, the fault temperature sensor can automatically detach from the main bus and will not affect normal working of other sensor in network. so to solve the problem of a certain sensor or branchs damage causing the paralysis of entire bus. the length of detecting temperature bus can reach more than 500 meters. these all make system maintenance and expansion easy. the experiments show that this system is characterized by high intelligence, high-precision, capability of making temperature test on multi-points and compensating function. the method has a good applicable value to the temperature test.introduction the change of fermentation temperature has a greater impact on the quality of beer in the process of beer production. many fermentation tanks are used to ferment beer in a brewery. a few sensors are installed in each fermentation tank to measure the temperature of liquid. the temperature monitoring system is characterized by greater number of temperature measurement points, the temperature measurement points are relatively concentrated.the traditional temperature detection system is composeof sensor, transmitter, a/d converter and so on. when there exist many detected points, the more transmitter and junction wires are needed, which not only makes the cost increase, and also brings us many inconvenience. dallas corp of united states first produced 1-wire digital temperature sensor ds1820, and then an enhanced product ds18b20 is released. the ds18b20 is a kind of digital temperature sensor of high integration, which consists of 64-bit laser rom, temperature sensor, 1-wire interface, scratchpad ram, temperature alarm triggers th and tl, 8-bit crc generator, control logic and parasitic power 1. the measuring temperatures of ds18b20 is range from -55c to +125c, which precision is 0.5c and resolution is programmable from 9 to 12 bits. it adopts 3-pin (gnd, dq, vdd), to-92 package. each ds18b20 has the unique 64-bit laser rom address code 1. a lot of ds18b20 can be connected to the same bus to detect the temperature without any external components. this feature is very well suitable for multi-point distributed temperature detection, and is convenient to constitute bus-type temperature detection system.the composition of the system the composition of temperature monitoring system of beer fermentation is shown in figure 1. industrial computer is responsible for the work of displaying temperature data, generating the curve of temperature change, and temperature chart printing and so on. temperature detector can be connected to industrial computers through the rs-232 interface. it controls the working condition of all the temperature sensors through transmission bus, and collects temperature data of 18 fermentation tanks in accordance with industrial computer commands. temperature detector is connected to 3 bus converter through the transmission bus, each bus converter can be connected to 6 fermentation tanks; there are 3 temperature sensors (ds18b20) in each fermentation tank. the temperature monitoring system contains 54 temperature measurement points in 18 fermentation tanks. transmission bus adopts the four-core cables;temperature detector provides power supply for bus converter and ds18b20 through transmission bus. there is a bus driver in temperature detector; it can drive more than 500 meters transmission bus. if you need increase the number of temperature measurement points, more bus converters can be connected to transmission bus in order to achieve linking of more ds18b20s. the number of the ds18b20 can be connected up to more than 300 at most.the design of temperature detector the composition of the temperature detector is shown in figure 2, at89c51 microcontroller is the core of the temperature detector to control the work of the various circuits. control program is stored in the mcus internal program memory. data memory saves the temperature data of each detection point. 64-bit code memory saves laser rom code of each temperature sensor (ds18b20). mcus serial signals are converted to rs-232c standard through rs-232 interface to realize the connection of industrial computer and the temperature detector. bus driver extends the driving capability of mcus i/o port to drive the transmission bus, in order to obtain further transmission distance. watchdog and reset circuit can provide power-on reset for the microcontroller, they can also provide reset signal when program has been confused by accidentally interfering. display is used to show the current number of fermentation tanks and temperature value of 3 sensors in fermentation tanks. the keyboard is used to control the temperature detector starting and stopping, but also enter the testing cycle and other control parameter.temperature detector can work independently, and display the number of fermentation tank and temperature value of 3 detected points in this tank, the range of temperature shown is -19.9c 99.9c. the number of tank shown can automatically change in cycle. time shown can be set arbitrarily during 199 seconds. temperature detector is also able to accept orders of industrial computer, it transmits the temperature value to the industrial computer, and then the industrial computer completes data processing. the design of bus driver and bus converter theoretically, lots of ds18b20s can be connected to one bus in parallel. however, the operating time slot of ds18b20 is fixed, and the width of many control impulses is so narrow that it is only few microseconds. in fact, we can seldom meet the need of the operating time slot of ds18b20 because of the limit of driving ability and distributing parameters. especially the increase of distributing capacitance of the over-long bus will make the distortion of waveform unavoidable, so the read/write error occurs. the recommended length of the bus by the dallas corporation is only 100 meters, and 20 ds18b20s can be connected to it at same time, hence, the application is limited 2,4. in order to solve this problem, we have designed transmission bus and its driver. the composition of bus driver and bus converter is shown in figure 3. transmission bus includes two signal lines txd and rxd. bus driver adopts 74hc367-type logical circuit to expand the driving ability of txd port in at89c51, thus it completes to drive txd line of transmission bus. the length of bus can be reached 500 meters. multiple bus converters can be connected to a transmission bus to form “tree” or “star” network. bus converter connects the transmission bus and the temperature sensor ds18b20 and completes the signal conversion between them. ds18b20 return signal is transmitted to the terminal rxd of the bus through the driver. the driver in bus converter also uses 74hc367-type logic circuit.the driver we mention here is different with the address switch of dallas corporation microlans network 3. the drivers on the bus are all connected to each other. when the skipping rom command is sent to ds18b20s, all ds18b20s existing on the bus can receive it. this feature allows us to start temperature conversion of all the ds18b20s existing on the same bus. the temperature detector can acquire the temperature of the different serial number detecting-point by sending different address. this will greatly reduce the temperature detection cycle, thereby increasing the temperature detection speed.the technology of hardware fault detecting when one power line or data line of any ds18b20 in the system is short to the ground, it will cause the whole bus stop working. to avoid this problem, we have designed hardware fault detecting and processing circuits for the system. on the one hand, it limits the short circuit current under 10ma; on the other hand disconnects the failure branch from the transmission bus. the composition of hardware fault detecting and processing circuit see figure 3. fault detecting circuit tests the logic level of 1-wire interface, when the logic level is high, its output signal is “1”and driver of converter is shutdown; when the logic level is low, its output signal is “0” and driver of converter is open. if logic level is low and its duration is more than 10ms, according to these phenomena, we can judge hardware failure occurring, temporality, the output signal is “1”, and the driver of converter will be a permanent shutdown. thus, only failure ds18b20 is disconnected from transmission bus, the other ds18b20s can work normally.although a bus converter can be connected to 30 ds18b20s, when short-circuit fault occurs in one of ds18b20s, the other 29 ds18b20s will stop working. if each ds18b20 can work independently and it has no effect to others when there is short-circuit fault occurring in one of them, it is necessary for each ds18b20 equipped with a bus converter. one transmission bus can connect more than 300 converters. the design of management software software of the temperature monitoring system is developed under visual basic 6.0, it is responsible for the work of acquiring real-time temperature, sensor temperature compensating,displaying multi-point temperature value, showing temperature variation curve, the temperature value statements and the temperature variation curve printing. module of acquiring real-time temperature is realized through serial communication between the industrial computer and temperature detector. serial communication adopts rs-232c standard, the baud rate of data transfer is the 9600 bit/s, the data format is 8 data bits, 1 parity bit, and 1 stop bit. industrial computer collects temperature value of 54 test points in 18 fermentation tanks once every 1 minute, then temperature data is saved in the computer hard disk in the format of a text file, in order to generate the temperature statements and curves of temperature change.module of sensor temperature compensating is used to calibrate error of the sensor. it is 0.5c accuracy from -10c to +85c in ds18b20 1. in order to improve the measurement accuracy, we have set up temperature compensation for each one temperature measurement point in the management software. the range of temperature compensation is 5c, the resolution is 0.01c. temperature compensation data requires to be inputted manually.module of displaying multi-point temperature value is used to display the current temperature of the 54 test points in the 18 fermentation tanks; the display interface is shown in figure 4. you can find the number of fermentation tanks and temperature value of the three test points in fermentation tanks from monitor. three test points are ranked by the upper, middle and lower. the interface contains quick button of temperature curve, by clicking on the mouse, you can switch to the display interface of temperature change curve. it also displays the communications status and the number of the fermentation tank in which the temperature data is being sampled.conclusion with the use of digital temperature sensor ds18b20, a tree-like or star-like network topology is achieved, which simplifies the hardware design of the temperature monitoring system and reduces the cost of system. hardware fault detection technology and its continuous improvement make the reliability of temperature detection system greatly improved. bus driver and bus converters adopt 74hc series logic circuits, with very low static power consumption. the temperature monitoring system has been running for more than four years. the practice shows that the system is simple in connecting wire,convenient in maintenance, and is also low cost, high dependability and good effect. it has excellent application prospect. references 1 dallas semiconductor, ds18b20 programmable resolution 1-wire digital thermometer. (2003) 2 dallas semiconductor, microlan - in the long run, application note 108. (2001) 3 dallas semiconductor, complex microlans, application note 106. (2001) 4 dallas semiconductor, guidelines for reliable 1-wire networks, application note 148. (2002) advanced materials research vols. 108-111 (2010) pp 898-902 (2010) trans tech publications, switzerlanddoi:10.4028//amr.108-111.898基于ds18b20的啤酒发酵温度测控系统周芬萍 马鸿涛 隋秉栋 孙佳莫 河北工业大学信息科学与工程学院 中国，河北，石家庄050054 摘 要：本文介绍了一种在啤酒发酵时使用的温度检测系统。温度监控系统拓扑总线结构的特点是由工业计算机、温度检测器、总线转换器、传输总线、1-wire数字温度传感器ds18b20组成。四芯电缆是用来形成一个树形或星形网络，其中，存在于18发酵罐的54个数字温度传感器可以连接。温度传感器和计算机之间的连接导线的数量将大大减少。温度检测器提供电源通过四芯电缆为总线转换器和ds18b20。因为总线转换器采用了硬件故障检测技术，故障温度传感器可以从主总线自动分离，不会影响其他传感器的正常工作网络。因此解决了某个传感器或分支的损伤引起的整个总线瘫痪的问题。检测温度总线长度可达到500米以上。这些都使系统维护和扩展方便。实验表明，该系统的特点是高智能、高精度、多路温度检测的能力、补偿功能。该方法具有良好的应用价值对于温度检测。关键词：ds18b20，温度检测，啤酒发酵，总线驱动，故障检测介绍 在啤酒生产过程中温度的变化对啤酒的质量有较大的影响。在酿酒厂啤酒发酵时会用许多发酵罐，可以在每个发酵罐安装几个传感器来测量液体的温度。温度监控系统的特征在于拥有大量的温度测量点，但测温点比较集中。传统的温度检测系统由传感器、变送器、a / d转换器等等组成。当存在着许多检测点，需要更多的发射器和结线，这不仅使成本增加，同时也给我们带来了许多不便。美国dallas股份有限公司首次生产1-wire数字温度传感器ds1820 ，然后升级版产品ds18b20出产。该ds18b20是一种高集成度，它由64位的光刻rom 、温度传感器、1-wire接口、暂存ram 、温度报警触发器th和tl 、 8位crc生成器、控制逻辑和寄生功率 1 组成。ds18b20的温度测量范围从-55c至+125c ，其中精度为 0.5 ，分辨率为可编程的9至12位。它采用3引脚（gnd ，dq ，vdd ），to-92封装。每ds18b20具有独特的64位激光rom地址码 1 。很多ds18b20可以连接到同一总线上检测温度，无需任何外部元件。这个功能非常适合于多点分布式温度检测，并且可以方便地构成总线型的温度检测系统。系统组成啤酒发酵的温度监测系统的组成如图1示。工业计算机负责显示温度数据处理工作，生成温度变化曲线和打印温度图表等。温度检测仪可通过rs- 232接口连接到工业计算机。它通过传输总线控制所有温度传感器的工作状态，并根据工业计算机的命令收集18个发酵罐的温度数据。温度检测器通过传输总线连接到总线转换器中，每个总线转换器可以连接到6个发酵罐；每个发酵罐有3个温度传感器（ds18b20 ）。该温度监控系统在18发酵罐上分布了54个温度检测点。传输总线采用四芯电缆，温度检测器通过传输总线提供电源为总线转换器和ds18b20 。它可以驱动超过500米的传输总线。如果你需要增加温度测量点的数目，多总线转换器可以连接到传输总线，以便实现连接更多ds18b20。 ds18b20的数量可以被连接到超过300个。图1 温度检测系统的组成温度检测仪的设计 温度检测器的组成于图2中示，at89c51单片机是温度检测器控制各种电路工作的核心。控制程序存储在单片机的内部程序存储器中。数据存储器保存每个的温度检测点数据。 64位程序存储器保存每个温度传感器（ds18b20）的激光rom代码。图2温度探测器组成的框图mcu的串行信号通过rs-232接口转换为rs-232c标准，实现了工业计算机及温度检测器的连接。公交车司机扩展了驾驶mcu的i / o端口来驱动总线的传输，以便获得进一步的传输能力距离。看门狗和复位电路可以提供上电复位微控制器，它们也可以提供复位信号，当程序被混淆了意外干扰。显示器是用来表明发酵罐和3个传感器在发酵温度值的当前数量坦克。键盘用于控制温度检测器启动和停止，也进入测试周期等控制参数。温度检测器可以独立工作，并显示发酵罐的数量和的3个温度值的检测点在该罐中所示的温度范围是-19.9 c99.9 c。示槽的数目可以自动改变周期。显示时间可设置在1 99秒随意。温度检测器也能够接受的工业订单计算机，它发送该温度值的工业计算机，然后在工业计算机完成数据处理。总线驱动器和总线转换器设计理论理论上，大量的ds18b20芯片可以连接到一个总线上。然而，ds18b20的操作时段是固定的，并且许多控制脉冲的宽度是如此之窄，只有几微秒。事实上，我们很少能满足ds18b20的操作时段的需要，因为运行能力和分布参数的限制。尤其是增加散发的过度长的总线的电容会使波形的失真是不可避免的，所以发生读/写错误。dallas公司总线的长度建议只有100米，20 个ds18b20可以连接到它在同一时间，因此，该应用程序是有限制的2,4 。为了解决这个问题，我们设计了传输总线和它的驱动程序。该总线驱动器和总线转换器的组成如图3所示。传输总线包括两个信号线txd和rxd 。总线驱动采用74hc367型逻辑电路，扩大驱动txd端口在单片机at89c51的能力，从而完成对驱动txd线的传输总线。该总线长度可以达到500米。多个总线转换器可以连接到一个传输总线，形成“树”型或“星”型的网络。总线转换器连接传输总线和温度传感器 ds18b20 和完成它们之间的信号转换。 ds18b20返回的信号通过驱动器发送到总线的端子rxd 。在总线驱动器转换器还采用74