多路温度采集系统外文翻译文献
基于单片机的多路温度采集系统设计
ANYANG INSTITUTE OF TECHNOLOGY本科毕业论文基于单片机的多路温度采集系统设计Based on Single Chip Multi-channel Temperature AcquisitionSystem Design系（院）名称：电子信息与电气工程系专业班级： 0000级自动化00班学生姓名： 123指导教师姓名： 000指导教师职称：讲师000 年00月基于单片机的多路温度采集系统设计专业班级: 000级自动化00班学生姓名: 000指导教师: 000 职称: 讲师摘要：单片机系统的开发应用给现代工业测控领域带来了一次新的技术革命，自动化、智能化均离不开单片机的应用。
单片机是一种集CPU、RAM、ROM、I/O接口和中断系统等部分于一体的器件，只需要外加电源和晶振就可实现对数字信息的处理和控制。
单片机由于其微小的体积和极低的成本，广泛的应用于家用电器、工业控制等领域中。
温度控制系统是利用下位机设置温度上下限和实时温度的采集，并将结果传输到上位机。
以达到对温度的比较、控制。
本设计用MCS-51单片机为主要硬件，设计了包括温度采集，温度显示，系统控制，串口通信等外围电路。
而且对所设计电路给出了相应的软件设计，包括定时器初始化，串行口初始化和数据传输等程序。
在温度测量部分采用具有“一线总线”接口的数字传感器DS18B20，实现单线多点数据的采集。
多点温度检测与控制系统是典型的集散式控制系统。
由下位机、上位机、和通讯网络三部分组成。
下位机是基于单片机AT89C52和DS18B20的高精度温度采集系统，功能是对温度的检测与输出控制。
上、下位机之间通过RS-232总线构成网络系统。
关键词：MCS-51；DS18B20；温度采集；RS-232Based on Single Chip Multi-channel Temperature AcquisitionSystem DesignAbstract：The development and application of MCU (Micro Control Unit) have made a great change in many fields of modern industrial detect and control. Adopt Single-ChipMicrocomputer is it control convenient, simple, flexibility advantage such as being heavy to have not merely to control to go on to temperature to come, and can raise by technical indicator not to accuse of temperature by a large margin, thus can big improvement quality and the quantity of products. Because of the small scale, low price and high efficiency of MCU, it iswidely used in home appliances and industrial control.The temperature control system is uses in the lower position machine establishment temperature the lower limit, with real-time temperature gathering, transmits to on position machine. By achieves to the temperature comparison, the control，This design uses MCS-51 The monolithic integrated circuit is the main hardware, In order to realize design goal this design including temperature gathering, the temperature demonstrated that, the systems control, strung together periphery electric circuit and so on mouth correspondence. Moreover to design the electric circuit to produce the corresponding software design, including timer initialization, serial procedure and so on mouth initialization and data transmission. The 1-Wire bus digital thermometer DS18B20 is used to measure temperature. It can realize the 1-Wire multi-point collection.Several points of temperature examination and control system is typically concentrate-dispersesystem. It consists of up a machine, bottom a machine, and communication network. Bottom a machine is a high accuracy data collection system that bases on the microcontroller AT89C52 and the DS18B20 system. Its function is to temperature and output the control. The up machine and bottom machines constitute of network system, via RS-232 bus.Key words: MCS-51；Temperature gathering；DS18B20；RS-232目录摘要 (Ⅰ)Abstract (Ⅱ)引言 (1)第一章多路温度采集显示系统的设计要求与设计方案 (2)1.1系统设计任务和要求 (2)1.2课题分析 (2)1.3方案比较与方案论证 (3)1.4方案论证和选定 (5)第二章多路温度采集系统硬件的设计 (7)2.1总体分析 (7)2.2A T89C52单片机的性能及应用 (7)2.3DS18B20芯片简介 (10)2.4DS18B20与单片机的典型接口设计 (14)2.5DS18B20使用中注意事项 (16)2.6温度检测系统设计 (16)2.7硬件电路设计 (18)第三章多路温度采集系统的软件设计 (20)3.1程序流程图设计 (20)3.2程序设计 (20)3.3单通道显示 (23)3.4串行通信 (24)第四章系统的抗干扰技术 (25)4.1硬件抗干扰技术 (25)4.2软件抗干扰技术 (25)结论 (27)致谢 (28)参考文献 (29)附录1：DS18B20温度测量程序 (30)引言近些年计算机领域的变化令人目不暇接，而单片微型计算机（简称单片机），作为微型计算机家族中的一员、发展中的一个分支，以其体积小、单一电源、功能强、价格低廉、低功耗、运算速度快、可靠性高、面向控制等独特优点，越来越深受各个应用领域的关注和重视，应用十分广泛，发展极快。
外文翻译(供热站温度实时监测)
Heating temperature and pressure test Thermistors are inexpensive, easily-obtainable temperature sensors. They are easy to use and adaptable. Circuits with thermistors can have reasonable outout voltages - not the millivolt outputs thermocouples have. Because of these qualities, thermistors are widely used for simple temperature measurements. They're not used for high temperatures, but in the temperature ranges where they work they are widely used. Thermistors are temperature sensitive resistors. All resistors vary with temperature, but thermistors are constructed of semiconductor material with a resistivity that is especially sensitive to temperature. However, unlike most other resistive devices, the resistance of a thermistor decreases with increasing temperature. That's due to the properties of the semiconductor material that the thermistor is made from. For some, that may be counterintuitive, but it is correct. Here is a graph of resistance as a function of temperature for a typical thermistor. Notice how the resistance drops from 100 kW, to a very small value in a range around room temperature. Not only is the resistance change in the opposite direction from what you expect, but the magnitude of the percentage resistance change is substantial.Temperature Sensor - The Thermocouple You are at: Elements - Sensors - Thermocouples Return to Table of Contents A thermocouple is a junction formed from two dissimilar metals. Actually, it is a pair of junctions. One at a reference temperature (like 0 oC) and the other junction at the temperature to be measured. A temperature difference will cause a voltage to be developed that is temperature dependent. (That voltage is caused by something called the Seebeck effect.) Thermocouples are widely used for temperature measurement because they are inexpensive, rugged and reliable, and they can be used over a wide temperature range. In particular, other temperature sensors (like thermistors and LM35 sensors)are useful around room temperature, but the thermocouple can The Thermocouple Why Use thermocouples To Measure Temperature? They are inexpensive. They are rugged and reliable. They can be used over a wide temperature range. What Does A Thermocouple Look Like? Here it is. Note the two wires (of two different metals) joined in the junction. What does a thermocouple do? How does it work? The junction of two dissimilar metals produces a temperature dependent voltage. For a better description of how it works, click here. How Do You Use A Thermocouple? You measure the voltage the thermocouple produces, and convert that voltage to a temperature reading. It may be best to do the conversion digitally because the conversion can be fairly nonlinear. Things You Need To Know About Thermocouples A junction between two dissimilar metals produces a voltage. In the thermocouple, the sensing junction - produces a voltage that depends upon temperature. Where the thermocouple connects to instrumentation - copper wires? - you have two more junctions and they also produce a temperature dependent voltage. Those junctions are shown inside the yellow oval. When you use a thermocouple, you need to ensure that the connections are at some standard temperature, or you need to use an electronically compensated system that takes those voltages into account. If your thermocouple is connected to a data acquisition system, then chances are good that you have an electronically compensated system. Once we obtain a reading from a voltmeter, the measured voltage has to be converted to temperature. The temperature is usually expressed as a polynomial function of the measured voltage. Sometimes it is possible to get a decent linear approximation over a limited temperature range. There are two ways to convert the measured voltage to a temperature reading. Measure the voltage and let the operator do the calculations. Use the measured voltage as an input to a conversion circuit - either analog or digital. Let us look at some other types of base-metal thermocouples. Type T thermocouples arewidely used as are type K and Type N. Type K (Ni-Cr/Ni-Al) thermocouples are also widely used in the industry. It has high thermopower and good resistance to oxidation. The operating temperature range of a Type K thermocouple is from -269 oC to +1260 oC. However, this thermocouple performs rather poorly in reducing atmospheres. Type T (Cu/Cu-Ni) thermocouples can be used in oxidizing of inert atmospheres over the temperature range of -250 oC to +850 oC. In reducing or mildly oxidizing environments, it is possible to use the thermocouple up to nearly +1000 oC. Type N (Nicrosil/Nisil) thermocouples are designed to be used in industrial environments of temperatures up to +1200 oC. A polynomial equation used to convert thermocouple voltage to temperature (oC) over a wide range of temperatures. We can write the polynomial as: The coefficients, an are tabulated in many places. Here are the NBS polynomial coefficients for a type K thermocouple. (Source: T. J. Quinn, Temperature , Academic Press Inc.,1990) Type K Polynomial Coefficients n an 0 0.226584602 1 24152.10900 2 67233.4248 3 2210340.682 4 -860963914.9 5 4.83506x1010 6 -1.18452x1012 7 1.38690x1013 8 -6.33708x1013 What If The Surrounding Temperature Exceeds Limits? There are really no thermocouples that can withstand oxidizing atmospheres for temperatures above the upper limit of the platinum-rhodium type thermocouples. We cannot, therefore, measure temperature in such high temperature conditions. Other options for measuring extremely high temperatures are radiation or the noise pyrometer. For non-oxidizing atmospheres, tungsten-rhenium based thermocouples shows good performance up to +2750 oC. They can be used, for a short period, in temperatures up to +3000 oC. The selection of the types of thermocouple used for low temperature sensing is primarily based on materials of a thermocouple. In addition, thermopower at low temperatue is rather low, so measurement of EMF will be proportionally small as well.More Facts On Various Thermocouple Types A variety of thermocouples today cover a range of temperature from -250 oC to +3000 oC. The different types of thermocouple are given letter designations: B, E, J, K, R, S, T and N Types R,S and B are noble metal thermocouples that are used to measure high temperature. Within their temperature range, they can operate for a longer period of time under an oxidizing environment. Type S and type R thermocouples are made up of platinum (Pt) and rhodium (Rh) mixed in different ratios. A specific Pt/Rh ratio is used because it leads to more stable and reproducible measurements. Types S and R have an upper temperature limit of +1200 oC in oxidizing atmospheres, assuming a wire diameter of 0.5mm. Type S and type R thermocouples are made up of platinum (Pt) and rhodium (Rh) mixed in different ratios. A specific Pt/Rh ratio is used because it leads to more stable and reproducible measurements. Types S and R have an upper temperature limit of +1200 oC in oxidizing atmospheres, assuming a wire diameter of 0.5mm. Type B thermocouples have a different Pt/Rh ratio than Type S and R. It has an upper temperature limit of +1750 oC in oxidizing atmospheres. Due to an increased amount of rhodium content, type B thermocouples are no quite so stable as either the Type R or Type S. Types E, J, K, T, and N are base-metal thermocouples that are used for sensing lower temperatures. They cannot be used for sensing high temperatures because of their relatively low melting point and slower failure due to oxidation. Type B thermocouples have a different Pt/Rh ratio than Type S and R. It has an upper temperature limit of +1750 oC in oxidizing atmospheres. Due to an increased amount of rhodium content, type B thermocouples are no quite so stable as either the Type R or Type S. we will look into some differences between different base-metal thermocouples. Type E (Ni-Cr/Cu-Ni) thermocouples have an operating temperature range from -250 oC to +800 oC. Their use is less widespread than other base-metal thermocouples due to its low operating temperature. However,measurements made by a Type E have a smaller margin of error. 1000 hours of operation in air of a Type E thermocouple at +760 oC, having 3mm wires, shold not lead to a change in EMF equivalent to more than +1 oC. Type J (Fe/Cu-Ni) thermocouples are widely used in industry due to their high thermopower and low cost. This type of thermocouple has an operating temperature range from 0 oC to +760 oC. Links to Related Lessons Temperature Sensors Thermistors Thermocouples LM35s Other Sensors Strain Gages Temperature Sensor Laboratories Return to Table of ContentsExperiments With Temperature Sensors - Data Gathering Measuring temperature is the most common measurement task. There are numerous devices available for measuring temperature. Many of them are built using one of these common sensors. Thermistor Thermocouple LM35 Integrated Circuit Temperature Sensor You can get more information about these sensors by clicking the links above. Laboratory The purpose of this laboratory is to get time response data for the three sensors you were introduced to labs week. Here are links to LabVIEW programs you can use. NTempsHydra.vi - to measure temperature from the Hydra. NVoltsHydra.vi - to measure voltage from the Hydra. ResetHydra.vi - A "sub-vi" you need to reset the Hydra. 1Temp.vi - A sub-vi that will take one temperature measurement on the Hydra. 1VoltHydra.vi - A sub-vi that will take one voltage measurement on the Hydra. You should have all the files above on your desktop. You can click on each link and save to the desktop, or you can find the NMeas folder in my public space and copy the entire folder to the desktop (best). You only need to double click the NTemps or NVolts files to start and run them in LabVIEW - but they have to be taken out of the network folder! Once you have the files together in a single folder on your desktop, Start NTempsHydra.vi to measure temperature using the thermocouple attached to terminals 21 (yellow lead) and 22 (red lead).Note that these terminals (21 and 22) are the connections for channel 1 for the Hydra. (For example, if you were doing a manual temperature reading using the front panel, you would need to set to channel 1.) You need to connect the yellow lead of the thermocouple to the top connector for Channel #1 (Terminal #21) and the red lead of the thermocouple to the bottom connector (ground?) for Channel #1 (Terminal #22). Both of those connections are made to the connector strip on the top of the Hydra Data Acquisition Unit. Start NVoltsHydra.vi to measure voltages using the LM35 and the voltage divider circuit for the thermistor. Both sets of measurements should be taken from the front panel connection points on the Hydra. For both the LM35 and the thermistor circuit, you need to supply 5v to the circuit board. In your lab notebook record any circuitry you use, and any pertinent points regarding the equipment you use. Note any other features of each sensor that will help you for your project or make things more difficult. Do the following: Connect each sensor. Here are links to using each sensor in a measurement. Thermocouples LM35s Thermistors For each sensor you need to get data in two situations: As the sensor heats up (rising time constant behavior) As the sensor cools down to ambient temperature (decaying time constant behavior) That data should be stored in a computer file. Use a different, understandable name for each file. The program will prompt you for a file name. Suggested file names are things like ThermistorUp.txt, etc. Before you leave lab be sure that you can bring your data up in Excel (to test that you have a good data file) and that you can plot the data to see that it looks like what you expect. Estimate the following for each sensor. The time it will take for the sensor to get within 1oC when the sensor is in good thermal contact with the temperature environment being measured and the temperature sensor starts at 25 oC and goes to 50 oC. (That means to measure the time it takes to get to between 49 oC and 51 oC.) The time it will take for the sensor to get within 1oC of the final value when the sensoris in air at a constant temperature and the temperature sensor starts at 25oC and goes to 50oC. In other words, when will the temperature sensor reach 49oC? The time it will take for the sensor to get within 0.1oC for the two situations above. (i.e., between 49.9 oC and 50.1 oC.) The time it will take for the sensor to get within 1oC when the sensor is in good thermal contact with the temperature environment being measured and the temperature sensor starts at 50 oC and goes to 25 oC. Explain why there is a difference in the speed of the response in the various situations above. Your report should show calculations for the time constant(s) for each device, and should show the results using the three methods. Tabular presentation of the results is best. Finally, you should - as best possible - explain your results. Why would the time constant be different going up and going down.供热站温度压力实时检测热敏电阻很便宜，易于得到的温度传感器。
基于单片机的温度控制外文文献及中文翻译
Temperature Control Using a Microcontroller:An Interdisciplinary Undergraduate Engineering Design ProjectJames S. McDonaldDepartment of Engineering ScienceTrinity UniversitySan Antonio, TX 78212Abstract：This paper describes an interdisciplinary design project which was done under the author' s supervision by a group of four senior students in the Department of Engineering Science at Trinity University. The objective of the project was to develop a temperature control system for an air-filled chamber. The system was to allow entry of a desired chamber temperature in a prescribed range and to exhibit overshoot and steady-state temperature error of less than 1 degree Kelvin in the actual chamber temperature step response. The details of the design developed by this group of students, based on a Motorola MC68HC05 family microcontroller, are described. The pedagogical value of the problem is also discussed through a description of some of the key steps in the design process .It is shown that the solution requires broad knowledge drawn from several engineering disciplines including electrical, mechanical, and control systems engineering.1 IntroductionThe design project which is the subject of this paper originated from a real-world application.A prototype of a microscope slide dryer had been developed around an OmegaTM model -390 temperature controller, and the objective was to develop a custom temperature control system to replace the Omega system. The motivation was that a custom controller targeted specifically for the application should be able to achieve the same functionality at a much lower cost, as theOmega system is unnecessarily versatile and equipped to handle a wide variety of applications.The mechanical layout of the slide dryer prototype is shown in Figure 1. The main element of the dryer is a large, insulated, air-filled chamber in which microscope slides, each with a tissue sample encased in paraffin, can be set on caddies. In order that the paraffin maintain the proper consistency, the temperature in the slide chamber must be maintained at a desired (constant) temperature. A second chamber (the electronics enclosure) houses a resistive heater and the temperature controller, and a fan mounted on the end of the dryer blows air across the heater, carrying heat into the slide chamber. This design project was carried out during academic year 1996 一97 by four students under the author5 s supervision as a Senior Design project in the Department of Engineering Science at Trinity University. The purpose of this paper is to describe the problem and the students5 solution in some detail, and to discuss some of the pedagogical opportunities offered by an interdisciplinary design project of this type. The students' own report was presented at the 1997 National Conference on Undergraduate Research [1]. Section 2 gives a more detailed statement of the problem, including performance specifications, and Section 3 describes the students, design. Section 4 makes up the bulk of the paper, and discusses in some detail several aspects of the design process which offer unique pedagogical opportunities. Finally, Section 5 offers some conclusions.2 Problem StatementThe basic idea of the project is to replace the relevant parts of the functionality of an Omega -390 temperature controller using a custom-designed system. The application dictates that temperature settings are usually kept constant for long periods of time, but if s nonetheless important that step changes be tracked in a “reasonable” manner. Thus the main requirements boil down to• allowing a chamber temperature set-point to be entered,• displaying both set-point and actual temperatures, and• tracking step changes in set-point temperature with acceptable rise time, steady-state error, and overshoot.Top ViewFront View10.25” 6.25” Figure 1. Slide diyer ineclicmical layouiAlthough not explicitly a part of the specifications in Table 1, it was clear that the customer desired digital displays of set-point and actual temperatures, and that set-point temperature entry should be digital as well (as opposed to, say, through a potentiometer setting).3 System DesignThe requirements for digital temperature displays and setpoint entry alone are enough to dictate that a microcontrollerbased design is likely the most appropriate・ Figure 2 shows a block diagram of the students5 design.Figure 2. Temperature controller hardwcuv block diagramThe microcontroller, a MotorolaMC68HC705B16 (6805 for short), is the heart of the system. It accepts inputs from a simple four-key keypad which allow specification of the set-point temperature, and it displays both set-point and measured chamber temperatures using two-digit seven-segment LED displays controlled by a display driver. All these inputs and outputs are acmodated by parallel ports on the 6805. Chamber temperature is sensed using a pre-calibrated thermistor and input via one of the 6805' s analog-to-digital inputs. Finally, a pulse-width modulation (PWM) output on the 6805 is used to drive a relay which switches line power to the resistive heater off and on.Figure 3 shows a more detailed schematic of the electronics and their interfacing to the 6805. The keypad, a Storm 3K041103, has four keys which are interfaced to pins PA0{ PA3 of Port A, configured as inputs. One key functions as a mode switch. Two modes are sup ported: set mode and run mode. In set mode two of the other keys are used to specify the set-point temperature: one increments it and one decrements. The fourth key is unused at present. The LED displays aredriven by a Harris Semiconductor ICM7212 display driver interfaced to pins PB0IPB6 of Port B, configured as outputs. The temperature-sensing thermistor drives, through a voltage divider, pin ANO (one of eight analog inputs). Finally, pin PLMA (one of two PWM outputs) drives the heater relay.Figure 3. Schematic ofinicrocontroUer boardSoftware on the 6805 implements the temperature control algorithm, maintains the temperature displays, and alters the set-point in response to keypad inputs. Because it is not plete at this writing, software will not be discussed in detail in this paper. The control algorithm in particular has not been determined, but it is likely to be a simple proportional controller and certainly not more plex than a PID. Some control design issues will be discussed in Section 4,however.4 The Design ProcessAlthough essentially the project is just to build a thermostat, it presents many nice pedagogical opportunities. The knowledge and experience base of a senior engineering undergraduate are just enough to bring him or her to the brink of a solution to various aspects of the problem. Yet, in each case, realworld considerations plicate the situation significantly.Fortunately these plications are not insurmountable, and the result is a very beneficial design experience. The remainder of this section looks at a few aspects of the problem which present the type of learning opportunity just described. Section 4.1 discusses some of the features of a simplified mathematical model of the thermal properties of the system and how it can be easily validated experimentally. Section 4.2 describes how realistic control algorithm designs can be arrived at using introductory concepts in control design. Section 4.3 points out some important deficiencies of such a simplified modeling/control design process and how they can be overe through simulation. Finally, Section 4.4 gives an overview of some of the microcontroller-related design issues which arise and learning opportunities offered.4.1 MathematicalModelLumped-element thermal systems are described in almost any introductory linear control systems text, and just this sort of model is applicable to the slide dryer problem. Figure 4 shows a second-order lumped-element thermal model of the slide dryer. The state variables are the temperatures Ta of the air in the box and Tb of the box itself. The inputs to the system are the power output q(t) of the heater and the ambient temperature T¥. ma and mb are the masses of the air and the box, respectively, and Ca and Cb their specific heats. p1 and JJ2 are heat transfercoefficients from the air to the box and from the box to the external world, respectively.If s not hard to show that the (linearized) state equationscorresponding to Figure 4 are 〃皿方 - 〃坊-“1(爲r — Tb) (1) “1(爲一 Tb) _ 'Tb — TJ (2) Taking Laplace transforms of (1) and (2) and solving for Ta(s), which is the output of interest, gives the following open-loop model of the thermal system:加)•K(x z s + 1) 1 Twhere K is a constant and D(s) is a second-order polynomial.K, tz, and the coefficients of D(s) are functions of the variousparameters appearing in (1) and (2).Of course the various parameters in (1) and(2) are pletely unknown, but if s not hard to show that, regardless of their values, D(s) has two real zeros. Therefore the main transfer function of interest (which is the one from Q(s), since we J II assume constant ambient temperature) can be written_ 爲⑸ _ Kg+ 1)力 W (^15+1)(^25 4- 1)Moreover, it' s not too hard to show that 1 =tp1 <1=tz <1 =tp2, i.e., that the zero lies between the two poles. Both of these are excellent exercises for the student, and the result is the openloop pole-zero diagram of Figure 5.q ⑴Figure 4. Luinped-elemeiu the/刀modelaqObtaining a plete thermal model, then, is reduced to identifying the constant K and the three unknown time constants in (3). Four unknown parameters is quite a few, but simple experiments show that 1=tp1 _ Utz; 1=tp2 so that tz;tp2 _ 0 are good approximations. Thus the open-loop system is essentially first-order and can therefore be writtenK%($)- ⑷(where the subscript p1 has been dropped).Simple open-loop step response experiments show that,for a wide range of initial temperatures and heat inputs, K _0:14 _=W and t _ 295 s.14.2 Control System DesignUsing the first-order model of (4) for the open-loop transfer function Gaq(s) and assuming for the moment that linear control of the heater power output q(t) is possible, the block diagram of Figure 6 represents the closed-loop system. Td(s) is the desired, or set-point, temperature,C(s) is the pensator transfer function, and Q(s) is the heater output in watts.Given this simple situation, introductory linear control design tools such as the root locus method can be used to arrive at a C(s) which meets the step response requirements on rise time, steady-state error, and overshoot specified in Table 1 .The upshot, of course, is that a proportional controller with sufficient gain can meet all specifications. Overshoot is impossible, and increasing gains decreases both steady-state error and rise time.Unfortunately, sufficient gain to meet the specifications may require larger heat outputs than the heater is capable of producing. This was indeed the case for this system, and the result is that the rise time specification cannot be met. It is quite revealing to the student how useful such an oversimplified model, carefully arrived at, can be in determining overall performance limitations.4.3 Simulation ModelGross performance and its limitations can be determined using the simplified model of Figure 6, but there are a number of other aspects of the closed-loop system whose effects on performance are not so simply modeled. Chief among these are• quantization error in analog -to-digital conversion of the measured temperature and-the use of PWM to control the heater.Both of these are nonlinear and time-varying effects, and the only practical way to study them is through simulation (or experiment, of course).Figure 7 shows a SimulinkTM block diagram of the closed-loop system which incorporates these effects. A/D converter quantization and saturation are modeled using standard Simulink quantizer乙(s)Figure 6. Simplified block diagram of the closed-loop systemand saturation blocks. Modeling PWM is more plicated and requires a custom S-function to represent it.Figure 7. Siimilink block diagram of closed-loop systemThis simulation model has proven particularly useful in gauging the effects of varying the basic PWM parameters and hence selecting them appropriately. (I.e., the longer the period, the larger the temperature error PWM introduces. On the other hand, a long period is desirable to avoid excessive relay “chatter,” among other things.) PWM is often difficult for students to grasp, and the simulation model allows an exploration of its operation and effects which is quite revealing.4.4 The MicrocontrollerSimple closed-loop control, keypad reading, and display control are some of the classic applications of microcontrollers, and this project incorporates all three. It is therefore an excellent all-around exercise in microcontroller applications. In addition, because the project is to produce an actual packaged prototype, it won, t doto use a simple evaluation board with the I/O pins jumpered to the target system. Instead, if s necessary to develop a plete embedded application. This entails the choice of an appropriate part from the broad range offered in a typical microcontroller family and learning to use a fairly sophisticated development environment. Finally, a custom printed-circuit board for the microcontroller and peripherals must be designed and fabricated.Microcontroller Selection. In view of existing local expertise, the Motorola line of microcontrollers was chosen for this project. Still, this does not narrow the choice down much. A fairly disciplined study of system requirements is necessary to specify which microcontroller, out of scores of variants, is required for the job. This is difficult for students, as they generally lack the experience and intuition needed as wellas the perseverance to wade through manufacturers J selection guides.Part of the problem is in choosing methods for interfacing the various peripherals (e.g., what kind of display driver should be used?). A study of relevant Motorola application notes [2, 3, 4] proved very helpful in understandingwhat basic approaches are available, and what microcontroller/peripheral binations should be considered.The MC68HC705B16 was finally chosen on the basis of its availableA/D inputs and PWMoutputs as well as 24 digital I/O lines. In retrospect this is probably overkill, as only one A/D channel, one PWM channel, and 11 I/O pins are actually required (see Figure 3). The decision was made to err on the safe side because a plete development system specific to the chosen part was necessary, and the project budget did not permit a second such system to be purchased should the first prove inadequate.Microcontroller Application Development. Breadboarding of the peripheral hardware, development of microcontroller software, and final debugging and testing of a custom printed-circuit board for the microcontroller and peripherals all require a development environment of some kind. The choice of a development environment, like that of the microcontroller itself, can be bewildering and requires some faculty expertise. Motorola makes three grades of development environment ranging from simple evaluation boards (at around $100) to full-blown real-time in-circuit emulators (at more like $7500). The middle option was chosen for this project: the MMEVS, which consists of _ a platform board (which supports all 6805-family parts), _ an emulator module (specific to B-series parts), and _ a cable and target head adapter (package-specific). Overall, the system costs about $900 and provides, with some limitations, in-circuit emulation capability. It also es with the simple but sufficient software development environment RAPID [5].Students find learning to use this type of system challenging, but the experience they gain in real-world microcontroller application development greatly exceeds the typical first-course experience usingsimple evaluation boards.Printed-Circuit Board. The layout of a simple (though definitely not trivial) printed-circuit board is another practical learning opportunity presented by this project. The final board layout, with package outlines, is shown (at 50% of actual size) in Figure & The relative simplicity of the circuit makes manual placement and routing practical—in fact, it likely gives better results than automatic in an application like this—and the student is therefore exposed to fundamental issues of printed-circuit layout and basic design rules. The layout software used was the very nice package pcb,2 and the board was fabricated in-house with the aid of our staff electronics technician.Figure 8. Printed-circuit layout for imcrocoutroUer board中文时:单片机温度控制：一个跨学科的本科生工程设廿顶目JamesS.McDonald工程科学系三一大学德克萨斯州圣安东尼奥市78212摘嬰：本文所描述的是作者领导由皿个三一大学高年级学生组成的01臥进行的一个跨学科工程项目的设廿。
数字式多路温度采集系统论文
山东省大学生电子设计竞赛论文编号题目数字式多路温度采集系统学生姓名李东、刘平、柴强专业06 电子信息工程应用物理学指导教师张福安、葛汝明、范海涛、董文慧二OO七年五月一日多路温度数据采集系统目录1摘要、关键词 (2)2设计要求 (3)3系统方案 (3)3.1系统总体方案 (3)3.2方案论证 (3)4系统硬件设计 (4)4.1 61板电路设计 (4)4.2 传感器DS18B20的工作原理电路图 (5)4.3 按键和显示电路 (5)4.4键盘显示模块电路图 (5)5系统软件设计 (6)5.1 软件结构 (6)5.2软件总体设计 (6)5.3子程序设计 (8)6.多路温度数据采集系统的测试 (12)7结论与答谢词 (12)8考文献 (13)1．摘要：在日常生活和工业控制过程中，经常需要进行多路温度测量，并对温度的结果进行分析，以做出相应的处理。
本方案利用SOCE061A单片机作为核心控制器，通过两个DS18B20器件实现两路温度的实时采集和显示，且可以设置温度值，实现超温报警功能。
关键词：SPCE061A、DS18B20、LED键盘模组英文解释：In the daily life and in the industry controlled process, frequently needs to carry on the multi- spots temperature survey, and carries on the analysis to the temperature result, makes corresponding processing .This plan using the SPCE061A monolithic integrated circuit took the core controller, realizes two groups temperatures real-time gathering and the demonstration through two DS18B20 component, also may establish the temperature value, realizes ultra warm reports to the police the function.2.设计要求：利用SPCE061A单片机、DS18B20基本要求如下：1．2路温度的实时采集；2．温度通过数码管显示，分手动和自动两方式：自动状态循环显示各通道温度，每隔2秒切换一个通道；手动方式只显示被选择的通道温度；3．可以为每一个通道设置独立的报警温度；3.系统方案；3.1系统总体方案：系统整体硬件设计如图3.1-1所示，整个系统以SPCE061A为核心，前向通道包括DS18B20传感器输入电路，按键输入电路；后向通道包括：LED显示电路和语音输入电路。
数据采集系统中英文对照外文翻译文献
中英文对照外文翻译(文档含英文原文和中文翻译)Data Acquisition SystemsData acquisition systems are used to acquire process operating data and store it on，secondary storage devices for later analysis. Many or the data acquisition systems acquire this data at very high speeds and very little computer time is left to carry out any necessary, or desirable, data manipulations or reduction. All the data are stored on secondary storage devices and manipulated subsequently to derive the variables ofin-terest. It is very often necessary to design special purpose data acquisition systems and interfaces to acquire the high speed process data. This special purpose design can be an expensive proposition.Powerful mini- and mainframe computers are used to combine the data acquisition with other functions such as comparisons between the actual output and the desirable output values, and to then decide on the control action which must be taken to ensure that the output variables lie within preset limits. The computing power required will depend upon the type of process control system implemented. Software requirements for carrying out proportional, ratio or three term control of process variables are relatively trivial, and microcomputers can be used to implement such process control systems. It would not be possible to use many of the currently available microcomputers for the implementation of high speed adaptive control systems which require the use of suitable process models and considerable online manipulation of data.Microcomputer based data loggers are used to carry out intermediate functions such as data acquisition at comparatively low speeds, simple mathematical manipulations of raw data and some forms of data reduction. The first generation of data loggers, without any programmable computing facilities, was used simply for slow speed data acquisition from up to one hundred channels. All the acquired data could be punched out on paper tape or printed for subsequent analysis. Such hardwired data loggers are being replaced by the new generation of data loggers which incorporate microcomputers and can be programmed by the user. They offer an extremely good method of collecting the process data, using standardized interfaces, and subsequently performing the necessary manipulations to provide the information of interest to the process operator. The data acquired can be analyzed to establish correlations, if any, between process variables and to develop mathematical models necessary for adaptive and optimal process control.The data acquisition function carried out by data loggers varies from one to 9 in system to another. Simple data logging systems acquire data from a few channels while complex systems can receive data from hundreds, or even thousands, of input channels distributed around one or more processes. The rudimentary data loggers scan the selected number of channels, connected to sensors or transducers, in a sequential manner and the data are recorded in a digital format. A data logger can be dedicated in the sense that it can only collect data from particular types of sensors and transducers. It is best to use a nondedicated data logger since any transducer or sensor can be connected to the channels via suitable interface circuitry. This facility requires the use of appropriate signal conditioning modules.Microcomputer controlled data acquisition facilitates the scanning of a large number of sensors. The scanning rate depends upon the signal dynamics which means that some channels must be scanned at very high speeds in order to avoid aliasing errors while there is very little loss of information by scanning other channels at slower speeds. In some data logging applications the faster channels require sampling at speeds of up to 100 times per second while slow channels can be sampled once every five minutes. The conventional hardwired, non-programmable data loggers sample all the channels in a sequential manner and the sampling frequency of all the channels must be the same. This procedure results in the accumulation of very large amounts of data, some of which is unnecessary, and also slows down the overall effective sampling frequency. Microcomputer based data loggers can be used to scan some fast channels at a higher frequency than other slow speed channels.The vast majority of the user programmable data loggers can be used to scan up to 1000 analog and 1000 digital input channels. A small number of data loggers, with a higher degree of sophistication, are suitable for acquiring data from up to 15, 000 analog and digital channels. The data from digital channels can be in the form of Transistor- Transistor Logic or contact closure signals. Analog data must be converted into digital format before it is recorded and requires the use of suitable analog to digital converters (ADC)．The characteristics of the ADC will define the resolution that can be achieved and the rate at which the various channels can be sampled. An in-crease in the number of bits used in the ADC improves the resolution capability. Successive approximation ADC's arefaster than integrating ADC's. Many microcomputer controlled data loggers include a facility to program the channel scanning rates. Typical scanning rates vary from 2 channels per second to 10, 000 channels per second.Most data loggers have a resolution capability of ±0.01% or better, It is also pos-sible to achieve a resolution of 1 micro-volt. The resolution capability, in absolute terms, also depends upon the range of input signals, Standard input signal ranges are 0-10 volt, 0-50 volt and 0-100 volt. The lowest measurable signal varies form 1 t, volt to 50, volt. A higher degree of recording accuracy can be achieved by using modules which accept data in small, selectable ranges. An alternative is the auto ranging facil-ity available on some data loggers.The accuracy with which the data are acquired and logged-on the appropriate storage device is extremely important. It is therefore necessary that the data acquisi-tion module should be able to reject common mode noise and common mode voltage. Typical common mode noise rejection capabilities lie in the range 110 dB to 150 dB. A decibel (dB) is a tern which defines the ratio of the power levels of two signals. Thus if the reference and actual signals have power levels of N, and Na respectively, they will have a ratio of n decibels, wheren＝10 Log10（Na /Nr）Protection against maximum common mode voltages of 200 to 500 volt is available on typical microcomputer based data loggers.The voltage input to an individual data logger channel is measured, scaled and linearised before any further data manipulations or comparisons are carried out.In many situations, it becomes necessary to alter the frequency at which particu-lar channels are sampled depending upon the values of data signals received from a particular input sensor. Thus a channel might normally be sampled once every 10 minutes. If, however, the sensor signals approach the alarm limit, then it is obviously desirable to sample that channel once every minute or even faster so that the operators can be informed, thereby avoiding any catastrophes. Microcomputer controlledintel-ligent data loggers may be programmed to alter the sampling frequencies depending upon the values of process signals. Other data loggers include self-scanning modules which can initiate sampling.The conventional hardwired data loggers, without any programming facilities, simply record the instantaneous values of transducer outputs at a regular samplingin-terval. This raw data often means very little to the typical user. To be meaningful, this data must be linearised and scaled, using a calibration curve, in order to determine the real value of the variable in appropriate engineering units. Prior to the availability of programmable data loggers, this function was usually carried out in the off-line mode on a mini- or mainframe computer. The raw data values had to be punched out on pa-per tape, in binary or octal code, to be input subsequently to the computer used for analysis purposes and converted to the engineering units. Paper tape punches are slow speed mechanical devices which reduce the speed at which channels can be scanned. An alternative was to print out the raw data values which further reduced the data scanning rate. It was not possible to carry out any limit comparisons or provide any alarm information. Every single value acquired by the data logger had to be recorded eventhough it might not serve any useful purpose during subsequent analysis; many data values only need recording when they lie outside the pre-set low and high limits.If the analog data must be transmitted over any distance, differences in ground potential between the signal source and final location can add noise in the interface design. In order to separate common-mode interference form the signal to be recorded or processed, devices designed for this purpose, such as instrumentation amplifiers, may be used. An instrumentation amplifier is characterized by good common-mode- rejection capability, a high input impedance, low drift, adjustable gain, and greater cost than operational amplifiers. They range from monolithic ICs to potted modules, and larger rack-mounted modules with manual scaling and null adjustments. When a very high common-mode voltage is present or the need for extremely-lowcom-mon-mode leakage current exists（as in many medical-electronics applications），an isolation amplifier is required. Isolation amplifiers may use optical or transformer isolation.Analog function circuits are special-purpose circuits that are used for a variety of signal conditioning operations on signals which are in analog form. When their accu-racy is adequate, they can relieve the microprocessor of time-consuming software and computations. Among the typical operations performed are multiplications, division, powers, roots, nonlinear functions such as for linearizing transducers, rimsmeasure-ments, computing vector sums, integration and differentiation, andcurrent-to-voltage or voltage- to-current conversion. Many of these operations can be purchased in available devices as multiplier/dividers, log/antilog amplifiers, and others.When data from a number of independent signal sources must be processed by the same microcomputer or communications channel, a multiplexer is used to channel the input signals into the A/D converter.Multiplexers are also used in reverse, as when a converter must distribute analog information to many different channels. The multiplexer is fed by a D／A converter which continually refreshes the output channels with new information.In many systems, the analog signal varies during the time that the converter takes to digitize an input signal. The changes in this signal level during the conversion process can result in errors since the conversion period can be completed some time after the conversion command. The final value never represents the data at the instant when the conversion command is transmitted. Sample-hold circuits are used to make an acquisition of the varying analog signal and to hold this signal for the duration of the conversion process. Sample-hold circuits are common in multichannel distribution systems where they allow each channel to receive and hold the signal level.In order to get the data in digital form as rapidly and as accurately as possible, we must use an analog/digital (A/D) converter, which might be a shaft encoder, a small module with digital outputs, or a high-resolution, high-speed panel instrument. These devices, which range form IC chips to rack-mounted instruments, convert ana-log input data, usually voltage, into an equivalent digital form. The characteristics of A/D converters include absolute and relative accuracy, linearity, monotonic, resolu-tion, conversion speed, and stability. A choice of input ranges, output codes, and other features are available. The successive-approximation technique is popular for a large number ofapplications, with the most popular alternatives being the counter-comparator types, and dual-ramp approaches. The dual-ramp has been widely-used in digital voltmeters.D/A converters convert a digital format into an equivalent analog representation. The basic converter consists of a circuit of weighted resistance values or ratios, each controlled by a particular level or weight of digital input data, which develops the output voltage or current in accordance with the digital input code. A special class of D/A converter exists which have the capability of handling variable reference sources. These devices are the multiplying DACs. Their output value is the product of the number represented by the digital input code and the analog reference voltage, which may vary form full scale to zero, and in some cases, to negative values.Component Selection CriteriaIn the past decade, data-acquisition hardware has changed radically due to ad-vances in semiconductors, and prices have come down too; what have not changed, however, are the fundamental system problems confronting the designer. Signals may be obscured by noise, rfi，ground loops, power-line pickup, and transients coupled into signal lines from machinery. Separating the signals from these effects becomes a matter for concern.Data-acquisition systems may be separated into two basic categories:（1）those suited to favorable environments like laboratories -and（2）those required for hostile environments such as factories, vehicles, and military installations. The latter group includes industrial process control systems where temperature information may be gathered by sensors on tanks, boilers, wats, or pipelines that may be spread over miles of facilities. That data may then be sent to a central processor to provide real-time process control. The digital control of steel mills, automated chemical production, and machine tools is carried out in this kind of hostile environment. The vulnerability of the data signals leads to the requirement for isolation and other techniques.At the other end of the spectrum-laboratory applications, such as test systems for gathering information on gas chromatographs, mass spectrometers, and other sophis-ticated instruments-the designer's problems are concerned with the performing of sen-sitive measurements under favorable conditions rather than with the problem ofpro-tecting the integrity of collected data under hostile conditions.Systems in hostile environments might require components for wide tempera-tures, shielding, common-mode noise reduction, conversion at an early stage, redun-dant circuits for critical measurements, and preprocessing of the digital data to test its reliability. Laboratory systems, on the other hand, will have narrower temperature ranges and less ambient noise. But the higher accuracies require sensitive devices, and a major effort may be necessary for the required signal /noise ratios.The choice of configuration and components in data-acquisition design depends on consideration of a number of factors:1. Resolution and accuracy required in final format.2. Number of analog sensors to be monitored.3. Sampling rate desired.4. Signal-conditioning requirement due to environment and accuracy.5. Cost trade-offs.Some of the choices for a basic data-acquisition configuration include：1 ．Single-channel techniques.A. Direct conversion.B. Preamplification and direct conversion.C. Sample-hold and conversion.D. Preamplification, sample-hold, and conversion.E. Preamplification, signal-conditioning, and direct conversion.F. Preamplification, signal-conditioning, sample-hold, and conversion.2. Multichannel techniques.A. Multiplexing the outputs of single-channel converters.B. Multiplexing the outputs of sample-holds.C. Multiplexing the inputs of sample-holds.D. Multiplexing low-level data.E. More than one tier of multiplexers.Signal-conditioning may include:1. Radiometric conversion techniques.B. Range biasing.D. Logarithmic compression.A. Analog filtering.B. Integrating converters.C. Digital data processing.We shall consider these techniques later, but first we will examine some of the components used in these data-acquisition system configurations.MultiplexersWhen more than one channel requires analog-to-digital conversion, it is neces-sary to use time-division multiplexing in order to connect the analog inputs to a single converter, or to provide a converter for each input and then combine the converter outputs by digital multiplexing.Analog MultiplexersAnalog multiplexer circuits allow the timesharing of analog-to-digital converters between a numbers of analog information channels. An analog multiplexer consists of a group of switches arranged with inputs connected to the individual analog channels and outputs connected in common（as shown in Fig. 1）．The switches may be ad-dressed by a digital input code.Many alternative analog switches are available in electromechanical and solid-state forms. Electromechanical switch types include relays, stepper switches,cross-bar switches, mercury-wetted switches, and dry-reed relay switches. The best switching speed is provided by reed relays（about 1 ms）．The mechanical switches provide high do isolation resistance, low contact resistance, and the capacity to handle voltages up to 1 KV, and they are usually inexpensive. Multiplexers using mechanical switches are suited to low-speed applications as well as those having high resolution requirements. They interface well with the slower A/D converters, like the integrating dual-slope types. Mechanical switches have a finite life, however, usually expressed innumber of operations. A reed relay might have a life of 109 operations, which wouldallow a 3-year life at 10 operations/second.Solid-state switch devices are capable of operation at 30 ns, and they have a life which exceeds most equipment requirements. Field-effect transistors（FETs）are used in most multiplexers. They have superseded bipolar transistors which can introduce large voltage offsets when used as switches.FET devices have a leakage from drain to source in the off state and a leakage from gate or substrate to drain and source in both the on and off states. Gate leakage in MOS devices is small compared to other sources of leakage. When the device has a Zener-diode-protected gate, an additional leakage path exists between the gate and source.Enhancement-mode MOS-FETs have the advantage that the switch turns off when power is removed from the MUX. Junction-FET multiplexers always turn on with the power off.A more recent development, the CMOS-complementary MOS-switch has the advantage of being able to multiplex voltages up to and including the supply voltages. A±10-V signal can be handled with a ±10-V supply.Trade-off Considerations for the DesignerAnalog multiplexing has been the favored technique for achieving lowest system cost. The decreasing cost of A/D converters and the availability of low-cost, digital integrated circuits specifically designed for multiplexing provide an alternative with advantages for some applications. A decision on the technique to use for a givensys-tem will hinge on trade-offs between the following factors:1. Resolution. The cost of A/D converters rises steeply as the resolution increases due to the cost of precision elements. At the 8-bit level, the per-channel cost of an analog multiplexer may be a considerable proportion of the cost of a converter. At resolutions above 12 bits, the reverse is true, and analog multiplexing tends to be more economical.2. Number of channels. This controls the size of the multiplexer required and the amount of wiring and interconnections. Digital multiplexing onto a common data bus reduces wiring to a minimum in many cases. Analog multiplexing is suited for 8 to 256 channels; beyond this number, the technique is unwieldy and analog errors be-come difficult to minimize. Analog and digital multiplexing is often combined in very large systems.3. Speed of measurement, or throughput. High-speed A/D converters can add a considerable cost to the system. If analog multiplexing demands a high-speedcon-verter to achieve the desired sample rate, a slower converter for each channel with digital multiplexing can be less costly．4. Signal level and conditioning. Wide dynamic ranges between channels can be difficult with analog multiplexing. Signals less than 1V generally require differential low-level analog multiplexing which is expensive, with programmable-gain amplifiers after the MUX operation. The alternative of fixed-gain converters on each channel, with signal-conditioning designed for the channel requirement, with digital multi-plexing may be more efficient.5. Physical location of measurement points. Analog multiplexing is suitedfor making measurements at distances up to a few hundred feet from the converter, since analog lines may suffer from losses, transmission-line reflections, and interference. Lines may range from twisted wire pairs to multiconductor shielded cable, depending on signal levels, distance, and noise environments. Digital multiplexing is operable to thousands of miles, with the proper transmission equipment, for digital transmission systems can offer the powerful noise-rejection characteristics that are required for29 Data Acquisition Systems long-distance transmission.Digital MultiplexingFor systems with small numbers of channels, medium-scale integrated digital multiplexers are available in TTL and MOS logic families. The 74151 is a typical example. Eight of these integrated circuits can be used to multiplex eight A/D con-verters of 8-bit resolution onto a common data bus.This digital multiplexing example offers little advantages in wiring economy, but it is lowest in cost, and the high switching speed allows operation at sampling rates much faster than analog multiplexers. The A/D converters are required only to keep up with the channel sample rate, and not with the commutating rate. When large numbers of A/D converters are multiplexed, the data-bus technique reduces system interconnections. This alone may in many cases justify multiple A/D converters. Data can be bussed onto the lines in bit-parallel or bit-serial format, as many converters have both serial and parallel outputs. A variety of devices can be used to drive the bus, from open collector and tristate TTL gates to line drivers and optoelectronic isolators. Channel-selection decoders can be built from 1-of-16 decoders to the required size. This technique also allows additional reliability in that a failure of one A/D does not affect the other channels. An important requirement is that the multiplexer operate without introducing unacceptable errors at the sample-rate speed. For a digital MUX system, one can determine the speed from propagation delays and the time required to charge the bus capacitance.Analog multiplexers can be more difficult to characterize. Their speed is a func-tion not only of internal parameters but also external parameters such as channel, source impedance, stray capacitance and the number of channels, and the circuit lay-out. The user must be aware of the limiting parameters in the system to judge their ef-fect on performance.The nonideal transmission and open-circuit characteristics of analog multiplexers can introduce static and dynamic errors into the signal path. These errors include leakage through switches, coupling of control signals into the analog path, and inter-actions with sources and following amplifiers. Moreover, the circuit layout can com-pound these effects.Since analog multiplexers may be connected directly to sources which may have little overload capacity or poor settling after overloads, the switches should have a break-before-make action to prevent the possibility of shorting channels together. It may be necessary to avoid shorted channels when power is removed and a chan-nels-off with power-down characteristic is desirable. In addition to the chan-nel-addressing lines, which are normally binary-coded, it is useful to have inhibited or enable lines to turn all switches off regardless of the channel being addressed. This simplifies the external logic necessary to cascade multiplexers and can also be useful in certain modes of channeladdressing. Another requirement for both analog and digital multiplexers is the tolerance of line transients and overload conditions, and the ability to absorb the transient energy and recover without damage.数据采集系统数据采集系统是用来获取数据处理和存储在二级存储设备，为后来的分析。
数字温度传感器毕业论文中英文资料外文翻译文献[管理资料]
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毕业论文中英文资料外文翻译文献外文资料DS1722 Digital ThermometerWith scientific and technological progress and development of the types of temperature sensors increasingly wide range of application of the increasingly widespread, and the beginning analog toward digital, single-bus, dual-bus and bus-3 direction. And the number of temperature sensors because they apply to all microprocessor interface consisting of automatic temperature control system simulation can be overcome sensor and microprocessor interface need signal conditioning circuit and A / D converters advant ages of the drawbacks, has been widely used in industrial control, electronic transducers, medical equipment and other temperature control system. Among them, which are more representative of a digital temperature sensor DS18B20, MAX6575, the DS1722, MAX6636 other. This paper introduces the DS1722 digital temperature sensor characteristics, the use of the method and its timing. Internal structure and other relevant content.FEATURES:Temperature measurements require no external components;Measures temperatures from -55°C to +120°C. Fahrenheit equivalent is -67°F to +248°F;Thermometer accuracy is ±°C;Thermometer resolution is configurable from 8 to 12 bits (°C to °C resolution);Data is read from/written to via a Motorola Serial Peripheral Interface (SPI) or standard 3-wire serial interface;Wide analog power supply range ( - );Separate digital supply allows for logic;Available in an 8-pin SOIC (150 mil), 8-pin USOP, and flip chip package;PIN ASSIGNMENTFIGURE 1 PIN ASSIGNMENTPIN DESCRIPTION:SERMODE - Serial Interface Mode.CE - Chip Enable.SCLK - Serial Clock.GND – Ground.VDDA - Analog Supply Voltage.SDO - Serial Data Out.SDI - Serial Data In.VDDD - Digital Supply Voltage.DESCRIPTION:The DS1722 Digital Thermometer and Thermostat with SPI/3-Wire Interface provides temperature readings which indicate the temperature of the device. No additional components are required; the device is truly a temperature-to-digital converter. Temperature readings are communicated from the DS1722 over a Motorola SPI interface or a standard 3-wire serial interface. The choice of interface standard is selectable by the user. For applications that require greater temperature resolution, the user can adjust the readout resolution from 8 to 12 bits. This is particularly useful in applications where thermal runaway conditions must be detected quickly.For application flexibility, the DS1722 features a wide analog supply rail of - . A separate digital supply allows a range of to . The DS1722 is available in an 8-pin SOIC (150-mil), 8-pin USOP, and flip chip package.Applications for the DS1722 include personal computers/servers/workstations, cellular telephones, office equipment, or any thermally-sensitive system.OVERVIEW:A block diagram of the DS1722 is shown in Figure 2. The DS1722 consists offour major components:1. Precision temperature sensor.2. Analog-to-digital converter.3. SPI/3-wire interface electronics.4. Data registers.The factory-calibrated temperature sensor requires no external components. The DS1722 is in a power conserving shutdown state upon power-up. After power-up, the user may alter the configuration register to place the device in a continuous temperature conversion mode or in a one-shot conversion mode. In the continuous conversion mode, the DS1722 continuously converts the temperature and stores the result in the temperature register. As conversions are performed in the background, reading the temperature register does not affect the conversion in progress. In the one-shot temperature conversion mode, the DS1722 will perform one temperature conversion, store the result in the temperature register, and then eturn to the shutdown state. This conversion mode is ideal for power sensitive applications. More information on the configuration register is contained in the “OPERATION-Programming”section. The temperature conversion results will have a default resolution of 9 bits. In applications where small incremental temperature changes are critical, the user can change the conversion resolution from 9 bits to 8, 10, 11, or 12. This is accomplished by programming the configuration register. Each additional bit of resolution approximately doubles the conversion time. The DS1722 can communicate using either a Motorola Serial Peripheral Interface (SPI) or standard 3-wire interface. The user can select either communication standard through the SERMODE pin, tying it to VDDD for SPI and to ground for 3-wire. The device contains both an analog supply voltage and a digital supply voltage (VDDA and VDDD, respectively). The analog supply powers the device for operation while the digital supply provides the top rails for the digital inputs and outputs. The DS1722 was designed to be Logic-Ready.DS1722 FUNCTIONAL BLOCK DIAGRAM Figure 2OPERATION-Measuring Temperature:The core of DS1722 functionality is its direct-to-digital temperature sensor. The DS1722 measures temperature through the use of an on-chip temperature measurement technique with an operating range from -55°to +120°C. The device powers up in a power-conserving shutdown mode. After power-up, the DS1722 may be placed in a continuous conversion mode or in a one-shot conversion mode. In the continuous conversion mode, the device continuously computes the temperature and stores the most recent result in the temperature register at addresses 01h (LSB) and 02h (MSB). In the one-shot conversion mode, the DS1722 performs one temperature conversion and then returns to the shutdown mode, storing temperature in the temperature register. Details on how to change the setting after power up are contained in the “OPERATION-Programming”section. The resolution of the temperature conversion is configurable (8, 9, 10, 11, or 12 bits), with 9-bit readings the default state. This equates to a temperature resolution of °C, °C, °C, °C, or °C. Following each conversion, thermal data is stored in the thermometer register in two’s complement format; the information can be retrieved over the SPI or 3-wire interface with the address set to the temperature register, 01h (LSB) and then 02h (MSB). Table 2 describesthe exact relationship of output data to measured temperature. The table assumes the DS1722 is configured for 12-bit resolution; if the evince is configured in a lower resolution mode, those bits will contain 0s. The data is transmitted serially over the digital interface, MSB first for SPI communication and LSB first for 3-wire communication. The MSB of the temperature register contains the “sign” (S) bit, denoting whether the temperature is positive or negative. For Fahrenheit usage, a lookup table or conversion routine must be used.AddressLocation S 2625242322212002h MSB (unit = ℃) LSB2-12-22-32-40 0 0 0 01hTEMPERATURE DIGITAL OUTPUT(BINARY) DIGITAL OUTPUT(HEX)+120℃0111 1000 0000 0000 7800h+ 0001 1001 0001 0000 1910h+ 0000 1010 0010 0000 0a20h+ 0000 0000 1000 0000 0080h0 0000 0000 0000 0000 0000h1111 1111 1000 0000 Ff80h1111 0101 1110 0000 F5e0h1110 0110 1111 0000 E6f0h-55 1100 1001 0000 0000 C900h OPERATION-Programming:The area of interest in programming the DS1722 is the Configuration register. All programming is done via the SPI or 3-wire communication interface by selecting the appropriate address of the desired register location. Table 3 illustrates the addresses for the two registers (configuration and temperature) of the DS1722.Register Address Structure Table 3CONFIGURATION REGISTER PROGRAMMING:The configuration register is accessed in the DS1722 with the 00h address for reads and the 80h address for writes. Data is read from or written to the configuration register MSB first for SPI communication and LSB first for 3-wire communication. The format of the register is illustrated in Figure 2. The effect each bit has on DS1722 functionality is described below along with the power-up state of the bit. The entire register is volatile, and thus it will power-up in the default state.CONFIGURATION/STATUS REGISTER Figure 21SHOT = One-shot temperature conversion bit. If the SD bit is "1", (continuous temperature conversions are not taking place), a "1" written to the 1SHOT bit will cause the DS1722 to perform one temperature conversion and store the results in the temperature register at addresses 01h (LSB) and 02h (MSB). The bit will clear itself to "0" upon completion of the temperature conversion. The user has read/write access to the 1SHOT bit, although writes to this bit will be ignored if the SD bit is a "0", (continuous conversion mode). The power-up default of the one-shot bit is "0".R0, R1, R2 = Thermometer resolution bits. Table 4 below defines the resolution of the digital thermometer, based on the settings of these 3 bits. There is a direct tradeoff between resolution and conversion time, as depicted in the AC Electrical Characteristics. The user has read/write access to the R2, R1 and R0 bits and the power-up default state is R2="0", R1="0", and R0="1" (9-bit conversions).THERMOMETER RESOLUTION CONFIGURATION Table 4SD = Shutdown bit. If SD is "0", the DS1722 will continuously perform temperature conversions and store the last completed result in the temperature register. If SD is changed to a "1", the conversion in progress will be completed and stored and then the device will revert to a low-power shutdown mode. The communication port remains active. The user has read/write access to the SD bit and the power-up default is "1" (shutdown mode).SERIAL INTERFACE:The DS1722 offers the flexibility to choose between two serial interface modes. The DS1722 can communicate with the SPI interface or with a standard 3-wire interface. The interface method used is determined by the SERMODE pin. When this pin is connected to VDDD SPI communication is selected. When this pin is connected to ground, standard 3-wire communication is selected.SERIAL PERIPHERAL INTERFACE (SPI):The serial peripheral interface (SPI) is a synchronous bus for address and data transfer. The SPI mode of serial communication is selected by tying the SERMODE pin to VDDD. Four pins are used for the SPI. The four pins are the SDO (Serial Data Out), SDI (Serial Data In), CE (Chip Enable), and SCLK (Serial Clock). The DS1722 is the slave device in an SPI application, with the microcontroller being the master. The SDI and SDO pins are the serial data input and output pins for the DS1722, respectively. The CE input is used to initiate and terminate a data transfer. The SCLK pin is used to synchronize data movement between the master (microcontroller) and the slave (DS1722) devices. The shift clock (SCLK), which is generated by the microcontroller, is active only when CE is high and during address and data transfer to any device on the SPI bus. The inactive clock polarity is programmable in somemicrocontrollers. The DS1722 offers an important feature in that the level of the inactive clock is determined by sampling SCLK when CE becomes active. Therefore, either SCLK polarity can be accommodated. There is one clock for each bit transferred. Address and data bits are transferred in groups of eight, MSB first.3-WIRE SERIAL DATA BUS:The 3-wire communication mode operates similar to the SPI mode. However, in 3-wire mode, there is one bi-directional I/O instead of separate data in and data out signals. The 3-wire consists of the I/O (SDI and SDO pins tied together), CE, and SCLK pins. In 3-wire mode, each byte is shifted in LSB first unlike SPI mode where each byte is shifted in MSB first. As is the case with the SPI mode, an address byte is written to the device followed by a single data byte or multiple data bytes.外文资料译文DS1722数字温度传感器随着科学技术的不断进步和发展，温度传感器的种类日益繁多，应用逐渐广泛，并且开始由模拟式向着数字式、单总线式、双总线式和三总线式发展。
单片机温度探测系统中英文对照外文翻译文献
中英文对照翻译附件1：外文资料翻译译文一种基于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DS18B20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。
毕业设计英文翻译-智能热能表控制器外文翻译-中英文文献对照翻译
外文资料与中文翻译外文资料：Intelligent thermal energy meter controllerAbstractA microcontroller based, thermal energy meter cum controller (TEMC) suitable for solar thermal systems has been developed. It monitors solar radiation, ambient temperature,fluid flow rate, and temperature of fluid at various locations of the system and computes the energy transfer rate. It also controls the operation of the fluid-circulating pumpdepending on the temperature difference across the solar collector field. The accuracyof energy measurement is ±1.5%. The instrument has been tested in a solar water heatingsystem. Its operation became automatic with savings in electrical energy consumption ofpump by 30% on cloudy days.1 IntroductionSolar water heating systems find wide applications in industry to conserve fossil fuel like oil, coal etc. They employ motor driven pumps for circulating water with on-offcontrollers and calls for automatic operation. Reliability and performance of the system depend on the instrumentation and controls employed. Multi-channel temperature recorders, flow meters, thermal energy meters are the essential instruments for monitoring andevaluating the performance of these systems. A differential temperature controller (DTC) is required in a solar water heating system for an automatic and efficient operation ofthe system. To meet all these requirements, a microcontroller based instrument wasdeveloped. Shoji Kusui and Tetsuo Nagai [1] developed an electronic heat meter formeasuring thermal energy using thermistors as temperature sensors and turbine flow meter as flow sensor.2 Instrument detailsThe block diagram of the microcontroller (Intel 80C31) based thermal energy meter cum controller is shown in Fig. 1. RTD (PT100, 4-wire) sensors are used for the temperaturemeasurement of water at the collector field inlet, outlet and in the tank with appropriate signal conditioners designed with low-drift operational amplifiers. A precision semiconductor temperature sensor (LM335) is used for ambient temperature measurement. A pyranometer, having an output voltage of 8.33 mV/kW/m2, is used for measuring the incident solar radiation. To monitor the circulating fluid pressure, a sensor with 4–20 mA output is used. This output is converted into voltage using an I-V converter. All these outputsignals are fed to an 8-channel analog multiplexer (CD4051). Its output is fed to adual-slope 12-bit A/D converter (ICL7109). It is controlled by the microcontroller through the Programmable Peripheral Interface (PPI-82C55).Fig. 1. Block diagram of thermal energy meter cum controller.A flow sensor (turbine type) is used with a signal conditioner to measure the flowrate. Its output is fed to the counter input of the microcontroller. It is programmed tomonitor all the multiplexed signals every minute, compute the temperature difference,energy transfer rate and integrated energy. A real-time clock with MM58167 is interfacedto the microcontroller to time-stamp the logged data. An analog output (0–2 V) is provided using D/A converter (DAC-08) to plot both the measured and computed parameters. A 4×4 matrix keyboard is interfaced to the microcontroller to enter the parameters like specificheat of liquid, data log rate etc. An alphanumeric LCD display (24-character) is alsointerfaced with the microcontroller to display the measured variables. The serialcommunication port of the microcontroller is fed to the serial line driver and receiver(MAX232). It enables the instrument to interface with the computer for down-loading thelogged data. A battery-backed static memory of 56K bytes is provided to store the measured parameters. Besides data logging, the instrument serves as a DTC. This has been achievedby interfacing a relay to the PPI. The system software is developed to accept thedifferential temperature set points (ΔT on and ΔT off) from the keyboard. An algorithmsuitable for on-off control having two set-points is implemented to control the relays.3 Instrument calibrationThe amount of energy transferred (Q) is :Where = mass flows rate of liquid kg/s ; V = volumetric flow rate (l/h) ; ρ= density of water (kg/l) ; Cp = specific heat (kJ/kg°C); and ΔT = temperature difference between hot and cold (°C).The accuracy in energy measurement depends on the measurement accuracy of individual parameters. Temperature measurement accuracy depends on the initial error in the sensorand the error introduced due to temperature drifts in the signal conditioners and the A/D converter. The temperature sensor is immersed in a constant temperature bath (HAAKE B ath-K, German), whose temperature can be var ied in steps of 0.1°C. A mercury glass thermometer (ARNO A MARELL, Germany) with a resolution of 0.05°C is also placed along with PT100 sensor in the bath. This is compared with the instrument readings. The accuracy of the instrument in temperature measurem ent is ±0.1°C. Hence, the accuracy in differential temperature measurement is ±0.2°C.The flow sensor having a maximum flow rate of 1250 l/h is used for flow measurement.It is calibrated by fixing it in the upstream of a pipeline of length 8 m. The sensor output is connected to a digital frequency counter to monitor the number of pulses generated withdifferent flow rates. Water collected at the sensor outlet over a period is used forestimating the flow rate. The K-factor of the sensor is 3975 pulses/l. The uncertaintyin flow measurement is ±0.25% at 675 l/h. Uncertainties in density and specific heat ofwater are ±0.006 kg/l and ±0.011 kJ/kg°C respectively.Maximum amount of energy collection (Q) = 675×0.98×4.184×15/3600 = 11.53kW. Uncertainty in energy measurementωq/Q = [(ωv/V)2 + (ωρ/ρ)2 + (ωcp/Cp)2+(ωt/T )2]1/2.Inaccuracy in electronic circuitry is ±0.03 kW.The net inaccuracy in energy measurement is ±1.5%4 Field testThe instrument is incorporated in a solar water heating system as shown in Fig. 2.It consists of five solar flat plate collectors having an absorber area of 1.6 m2 each. The absorber is a fin and tube extruded from aluminium and painted with matt black paint. The collectors are mounted on a rigid frame facing south at an angle equal to the latitude of Bangalore (13°N). They are arranged in parallel configuration and connected to athermally insulated 500 l capacity storage tank. A 0.25 hp pump is used for circulatingthe water through the collector field. All the pipelines are thermally insulated. Thetemperature sensors and the flow sensor are incorporated in the system as shown in Fig.2. The data on solar radiation, ambient temperature, water flow rate, solar collector inlet and outlet temperatures and the system heat output are monitored at regular intervals.Fig. 2. Solar water heating system with thermal energy meter cum controller.The performance of the solar water heating system with TEMC on a partial cloudy dayis shown in Fig. 3. It is observed that DTC switched OFF the pump around 14:40 h as thereis no further energy gain by the collector field. This in turn reduced the heat lossesfrom the collector to ambient. Experiments are conducted with and without DTC o n both sunny and cloudy days. The DTC operated system shows the savings in electrical energy by 30%on a partial cloudy day and 8% on a sunny day. The variation in system output with andwithout DTC i s around 3%. Thus the controller has not only served as an energy conservation device, but also switches ON/OFF the system automatically depending on the availabilityof solar radiation. The collector field output (shown in Fig. 3) is calculated by measuring the fluid flow rate using volumetric method and the temperature difference with anotherpair of standard thermometers. It is 16.86 kWh. It is compared with the instrument reading 17.18 kWh. Thus, the deviation is 1.9%. Fig. 3 shows that the solar collector fieldefficiency is 54% when the incident solar irradiation is 31.75 kWh.Fig. 3. Performance of SWH system with TEMC on a partial cloudy day.5 Concluding remarksTEMC is used as on-line instrument in solar water heating systems for the measurement of thermal energy, temperature, flow rate with simultaneous control on the operation ofthe pump t o save electrical energy and enhance the thermal energy collection. Since several options are provided in the instrument, it can be used for monitoring the energy transfer rate in other thermal systems.AcknowledgementsThe authors are thankful to Department of Science and Technology, Govt. of India forproviding the financial assistance to carry out the above work.References1. Shoji Kusui, Tetsuo Nagai. An electronic integrating heat meter. IEEE Trans. onInstrumentation and Measurement, 1990;39(5):785-789.中文翻译：智能热能表控制器摘要适用于太阳能热系统的单片机热能表控制器（TEMC）已经研制成功。
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多路温度采集系统外文翻译文献多路温度采集系统外文翻译文献(文档含中英文对照即英文原文和中文翻译)译文：多路温度传感器一温度传感器简介1.1温度传感器的背景在人类的生活环境中，温度扮演着极其重要的角色。
无论你生活在哪里，从事什么工作，无时无刻不在与温度打着交道。
自 18 世纪工业革命以来，工业发展对是否能掌握温度有着绝对的联系。
在冶金、钢铁、石化、水泥、玻璃、医药等等行业，可以说几乎%80 的工业部门都不得不考虑着温度的因素。
温度对于工业如此重要，由此推进了温度传感器的发展。
1.2温度传感器的发展传感器主要大体经过了三个发展阶段：模拟集成温度传感器。
该传感器是采用硅半导体集成工艺制成，因此亦称硅传感器或单片集成温度传感器。
此种传感器具有功能单一(仅测量温度)、测温误差小、价格低、响应速度快、传输距离远、体积小、微功耗等，适合远距离测温、控温，不需要进行非线性校准，外围电路简单。
它是目前在国内外应用最为普遍的一种集成传感器，典型产品有AD590、AD592、TMP17、LM135 等；模拟集成温度控制器。
模拟集成温度控制器主要包括温控开关、可编程温度控制器，典型产品有LM56、AD22105 和 MAX6509。
某些增强型集成温度控制器(例如 TC652/653)中还包含了A/D 转换器以及固化好的程序，这与智能温度传感器有某些相似之处。
但它自成系统，工作时并不受微处理器的控制，这是二者的主要区别；智能温度传感器。
能温度传感器(亦称数字温度传感器)是在20世纪90年代中期问世的。
它是微电子技术、计算机技术和自动测试技术(ATE)的结晶。
智能温度传感器内部都包含温度传感器、A/D 转换器、信号处理器、存储器(或寄存器)和接口电路。
有的产品还带多路选择器、中央控制器(CPU)、随机存取存储器(RAM)和只读存储器(ROM)。
智能温度传感器的特点是能输出温度数据及相关的温度控制量，适配各种微控制器(MCU)；并且它是在硬件的基础上通过软件来实现测试功能的，其智能化程度也取决于软件的开发水平。
温度传感器的发展趋势。
进入21世纪后，温度传感器正朝着高精度、多功能、总线标准化、高可靠性及安全性、开发虚拟传感器和网络传感器、研制单片测温系统等高科技的方向迅速发展。
1.3单点与多点温度传感器目前市场主要存在单点和多点两种温度测量仪表。
对于单点温测仪表，主要采用传统的模拟集成温度传感器，其中又以热电阻、热电偶等传感器的测量精度高，测量范围大，而得到了普遍的应用。
此种产品测温范围大都在-200℃~800℃之间，分辨率12位，最小分辨温度在0.001~0.01 之间。
自带LED显示模块，显示4位到16位不等。
有的仪表还具有存储功能，可存储几百到几千组数据。
该类仪表可很好的满足单个用户单点测量的需要。
多点温度测量仪表，相对与单点的测量精度有一定的差距，虽然实现了多路温度的测控，但价格昂贵。
针对目前市场的现状，本课题提出了一种可满足要求、可扩展的并且性价比高的单片机多路测温系统。
通过温度传感器 DS18B20采集，然后通过C51 单片机处理并在数码管上显示，可以采集室内或花房中四处不同位置的温度，用四个数码管来显示。
第一个数码管显示所采集的是哪一路，哪个通道；后三个数码管显示所采集通道的温度值，精确到0.1度。
二系统的实现及相关技术2.1．系统的实现系统的实现采用多线连接，就是四个DS1820分别连接到单片机的四个IO口，这种方案虽然占用单片机的四个IO口，但在单片机IO口不紧缺的情况下采用这种方案大大的简化了编程难度，缩短了设计周期，同时也能保证系统的稳定。
方案二的框图如“图1-1”所示图1-1 DS1820多线连接方案2.2.AT89C51单片机简介AT89C51是一种带4K字节FLASH存储器（FPEROM—Flash Programmable and Erasable Read Only Memory）的低电压、高性能CMOS 8位微处理器，俗称单片机。
AT89C2051是一种带2K字节闪存可编程可擦除只读存储器的单片机。
单片机的可擦除只读存储器可以反复擦除1000次。
该器件采用ATMEL高密度非易失存储器制造技术制造，与工业标准的MCS-51指令集和输出管脚相兼容。
由于将多功能8位CPU和闪烁存储器组合在单个芯片中，ATMEL的AT89C51是一种高效微控制器，AT89C2051是它的一种精简版本。
AT89C51单片机为很多嵌入式控制系统提供了一种灵活性高且价廉的方案。
外形及引脚排列如图“图1-2”所示图1-2 AT89C51引脚图主要特性：·与MCS-51 兼容·4K字节可编程FLASH存储器·寿命：1000写/擦循环·数据保留时间：10年·全静态工作：0Hz-24MHz·三级程序存储器锁定·128×8位内部RAM·32可编程I/O线·两个16位定时器/计数器·5个中断源·可编程串行通道·低功耗的闲置和掉电模式·片内振荡器和时钟电路管脚说明：VCC：供电电压。
GND：接地。
P0口：P0口为一个8位漏级开路双向I/O口，每脚可吸收8TTL门电流。
当P0口的管脚第一次写1时，被定义为高阻输入。
P0能够用于外部程序数据存储器，它可以被定义为数据/地址的第八位。
在FIASH编程时，P0 口作为原码输入口，当FIASH进行校验时，P0输出原码，此时P0外部必须被拉高。
P1口：P1口是一个内部提供上拉电阻的8位双向I/O口，P1口缓冲器能接收输出4TTL门电流。
P1口管脚写入1后，被内部上拉为高，可用作输入，P1口被外部下拉为低电平时，将输出电流，这是由于内部上拉的缘故。
在FLASH编程和校验时，P1口作为第八位地址接收。
P2口：P2口为一个内部上拉电阻的8位双向I/O口，P2口缓冲器可接收，输出4个TTL门电流，当P2口被写“1”时，其管脚被内部上拉电阻拉高，且作为输入。
并因此作为输入时，P2口的管脚被外部拉低，将输出电流。
这是由于内部上拉的缘故。
P2口当用于外部程序存储器或16位地址外部数据存储器进行存取时，P2口输出地址的高八位。
在给出地址“1”时，它利用内部上拉优势，当对外部八位地址数据存储器进行读写时，P2口输出其特殊功能寄存器的内容。
P2口在FLASH编程和校验时接收高八位地址信号和控制信号。
P3口：P3口管脚是8个带内部上拉电阻的双向I/O口，可接收输出4个TTL门电流。
当P3口写入“1”后，它们被内部上拉为高电平，并用作输入。
作为输入，由于外部下拉为低电平，P3口将输出电流（ILL）这是由于上拉的缘故。
RST：复位输入。
当振荡器复位器件时，要保持RST脚两个机器周期的高电平时间。
ALE/PROG：当访问外部存储器时，地址锁存允许的输出电平用于锁存地址的地位字节。
在FLASH编程期间，此引脚用于输入编程脉冲。
在平时，ALE端以不变的频率周期输出正脉冲信号，此频率为振荡器频率的1/6。
因此它可用作对外部输出的脉冲或用于定时目的。
然而要注意的是：每当用作外部数据存储器时，将跳过一个ALE脉冲。
如想禁止ALE的输出可在SFR8EH地址上置0。
此时， ALE只有在执行MOVX，MOVC指令是ALE才起作用。
另外，该引脚被略微拉高。
如果微处理器在外部执行状态ALE禁止，置位无效。
/PSEN：外部程序存储器的选通信号。
在由外部程序存储器取指期间，每个机器周期两次/PSEN有效。
但在访问外部数据存储器时，这两次有效的/PSEN信号将不出现。
/EA/VPP：当/EA保持低电平时，则在此期间外部程序存储器（0000H-FFFFH），不管是否有内部程序存储器。
注意加密方式1时，/EA将内部锁定为RESET；当/EA端保持高电平时，此间内部程序存储器。
在FLASH编程期间，此引脚也用于施加12V编程电源（VPP）。
XTAL1：反向振荡放大器的输入及内部时钟工作电路的输入。
XTAL2：来自反向振荡器的输出。
2.3.DS1820简介DALLAS最新单线数字温度传感器DS18B20简介新的"一线器件"体积更小、适用电压更宽、更经济 Dallas 半导体公司的数字化温度传感器DS1820是世界上第一片支持 "一线总线"接口的温度传感器。
一线总线独特而且经济的特点，使用户可轻松地组建传感器网络，为测量系统的构建引入全新概念。
DS18B20 "一线总线"数字化温度传感器同DS1820一样，DS18B20也支持"一线总线"接口，测量温度范围为-55°C~+125°C，在-10~+85°C 范围内,精度为±0.5°C。
现场温度直接以"一线总线"的数字方式传输，大大提高了系统的抗干扰性。
适合于恶劣环境的现场温度测量，如：环境控制、设备或过程控制、测温类消费电子产品等。
与前一代产品不同，新的产品支持3V~5.5V的电压范围，使系统设计更灵活、方便。
而且新一代产品更便宜，体积更小。
DS18B20可以程序设定9~12位的分辨率，精度为±0.5°C。
可选更小的封装方式，更宽的电压适用范围。
分辨率设定，及用户设定的报警温度存储在EEPROM中，掉电后依然保存。
DS18B20的性能是新一代产品中最好的！性能价格比也非常出色！DS1820的新性能:(1) 可用数据线供电，电压范围：3.0~5.5V；(2) 测温范围：-55~+125℃，在-10~+85℃时精度为±0.5℃；(3) 可编程的分辨率为9~12位，对应的可分辨温度分别为0.5℃、0.25℃、0.125℃和0.0625℃；(4) 12位分辨率时最多在750ms内把温度值转换为数字；(5) 负压特性：电源极性接反时，温度计不会因发热而烧毁，但不能正常工作。
DS1820的外形DS18B20内部结构主要由四部分组成：64位光刻ROM、温度传感器、非挥发的温度报警触发器TH和TL、配置寄存器。
DS18B20的管脚排列如“图1-3”所示。
内部结构如“图1-4”所示图1-3 DS18B20外形图(1) DQ为数字信号输入/输出端；(2) GND为电源地；(3) VDD为外接供电电源输入端（在寄生电源接线方式时接地）。
图1-4内部结构三调试仿真3.1.硬件仿真采用Proteus7Proteus 是英国 Labeenter electronics 公司研发的 EDA 工具软件。
Proteus 不仅是模拟电路、数字电路、模／数混合电路的设计与仿真平台，更是目前世界最先进、最完整的多种型号微控制器系统的设计与仿真平台。