集成温度传感器外文翻译
传感器中英文介绍
传感器中英文介绍(总5页) -CAL-FENGHAI.-(YICAI)-Company One1-CAL-本页仅作为文档封面,使用请直接删除. sensorssensors(English name: transducer/sensor) is a kind of detection device, can feel the measured information, and will feel information transformation according to certain rule become electrical signal output, or other form of information needed to satisfy theinformation transmission, processing, storage, display, record and control requirements.Sensor's features include: miniaturization, digital, intelligent, multi-functional, systematic and network. It is the first step of automatic detection and automatic control. The existence and development of the sensor, let objects have sensory, such as touch, taste and smell let objects become live up slowly. Usually accordingto its basic cognitive functions are divided into temperature sensor, light sensor, gas sensor, force sensor, magnetic sensor, moisture sensor, acoustic sensor, radiation sensitive element, color sensorand sensor etc. 10 major categories.temperature transducerTemperature sensors (temperature transducer) refers to can feel temperature translates into usable output signal of the sensor. The temperature sensor is the core part of the temperature measuring instrument, wide variety. According to measuring methods could be divided into two types: contact and non-contact, according to the sensor material and electronic component features divided into two categories, thermal resistance and thermocouple.1 principle of thermocoupleThermocouple is composed of two different materials of metal wire, the welded together at the end. To measure the heating part of the environment temperature, can accurately know the temperature of the hot spots. Because it must have two different material of the conductor, so called the thermocouple. Different material to make the thermocouple used in different temperature range, their sensitivityis also each are not identical. The sensitivity of thermocouplerefers to add 1 ℃ hot spot temperature changes, the output variation of potential difference. For most of the metal material supportther mocouple, this value about between 5 ~ 40 microvolt / ℃.As a result of the thermocouple temperature sensor sensitivityhas nothing to do with the thickness of material, use very fine material also can make the temperature sensor. Also due to the production of thermocouple metal materials have good ductility, the slight temperature measuring element has high response speed, can measure the process of rapid change.Its advantages are:(1)high precision measurement. Because of thermocouple direct contact with the object being measured, not affected by intermediate medium.(2)the measurement range. Commonly used thermocouple from1600 ℃ to 50 ℃ ~ + sustainable measurement, some special thermocouple minimum measurable to - 269 ℃ (e.g., gold iron nickel chrome), the h ighest measurable to + 2800 ℃ (such as tungsten rhenium).(3) simple structure, easy to use. Thermocouple is usually composed of two different kinds of metal wire, but is not limited by the size and the beginning of, outside has protective casing, so very convenient to use. The thermocouple type and structure of the form.2. The thermocouple type and structure formation(1)the types of thermocoupleThe commonly used thermocouple could be divided into two types: standard thermocouple and non-standard thermocouple. Standard thermocouple refers to the national standard specifies its thermoelectric potential and the relationship between temperature, permissible error, and a unified standard score table of thermocouple, it has with matching display instrument to choose from. Rather than a standard thermocouple or on the order of magnitude less than therange to use standardized thermocouple, in general, there is no uniform standard, it is mainly used for measurement of some special occasions.Standardized thermocouple is our country from January 1, 1988, thermocouple and thermal resistance of all production according toIEC international standard, and specify the S, B, E, K, R, J, T sevenstandardization thermocouple type thermocouple for our countryunified design.(2)to ensure that the thermocouple is reliable, steady work, the structure of thermocouple requirements are as follows:①of the two thermocouple thermal electrode welding must be strong;②two hot electrode should be well insulated between each other, in case of short circuit;③compensation wires connected to the free cod of a thermocouple to convenient and reliable;④protect casing thermal electrodes should be able to make sufficient isolation and harmful medium.3.The thermocouple cold end temperature compensationDue to the thermocouple materials are generally more expensive (especially when using precious metals), and the temperature measurement points are generally more far, the distance to the instrument in order to save materials, reduce cost, usually adopt the compensating conductor) (the free end of the cold junction of the thermocouple to the steady control of indoor temperature, connectedto the meter terminals. It must be pointed out that the role of the thermocouple compensation wire extension hot electrode, so that only moved to the control room of the cold junction of the thermocouple instrument on the terminal, it itself does not eliminate the cold end temperature change on the influence of temperature, cannot have the compensation effect. So, still need to take some of the other correction method to compensate of the cold end temperatureespecially when t0 indicates influence on measuring temperature 0 ℃.Must pay attention to when using thermocouple compensating conductor model match, cannot be wrong polarity, compensation conductor should be connected to the thermocouple temperature should not exceed 100 ℃.传感器传感器(英文名称:transducer/sensor)是一种检测装置,能感受到被测量的信息,并能将感受到的信息,按一定规律变换成为电信号或其他所需形式的信息输出,以满足信息的传输、处理、存储、显示、记录和控制等要求。
传感器技术论文中英文对照资料外文翻译文献
传感器技术论文中英文对照资料外文翻译文献Development of New Sensor TechnologiesSensors are devices that can convert physical。
chemical。
logical quantities。
etc。
into electrical signals。
The output signals can take different forms。
such as voltage。
current。
frequency。
pulse。
etc。
and can meet the requirements of n n。
processing。
recording。
display。
and control。
They are indispensable components in automatic n systems and automatic control systems。
If computers are compared to brains。
then sensors are like the five senses。
Sensors can correctly sense the measured quantity and convert it into a corresponding output。
playing a decisive role in the quality of the system。
The higher the degree of n。
the higher the requirements for sensors。
In today's n age。
the n industry includes three parts: sensing technology。
n technology。
and computer technology。
温度传感器外文翻译
英文翻译Temperature humidity sensorThe sensor in type many sensors, the temperature sensor and applies two aspects in its output both is second to and with it correlation temperature is an important physical parameter, he affects all physical, chemistry and biomedicine process march, regardless of in the industry, the agriculture, the scientific research, the national defense and people's daily life each aspect, the temperature survey and the control all is the extremely important with the electronic technology and the materials science development, to each kind of new thermal element and the temperature sensor request structure advanced, the performance is stable, satisfies the more and more high request which proposed to the temperature survey and the control.Sensor classification carries on classified resistance type PN according to the manufacture temperature sensor material and the principle of work to tie the type thermoelectricity type radiation formular operating region is refers to the resistance value to have the remarkable change temperature sensor along with the temperature change, it may transform directly the temperature as the electrical the operating temperature scope, its resistance the which increases along with the temperature ascension is called positive temperature coefficient (PTC); Its resistance number the which reduces along with the temperature t ascension is called negative temperature (NTC); The negative temperature which reduces suddenly along with the temperature rise is called critical (CTR) in a warm area internal resistance.1. PTC principle of the PTC r usually to use the (BaTio3) ceramic material, the pure BaTio3 ceramics have the extremely high electronic resistivity under often the temperature, above 108Ω · m, therefore is the insulator.If carries on the doping in BaTio3, may cause the BaTio3 semiconductor, for example: Mixes by %% rare-earth element, but causes it to become has under the normal temperature----10Ω · m N line of semiconductors .Has electricity semiconductor BaTio3, when the temperature achieved when Curie temperature T, it transforms by the tetragonal system into the cubic system, this time its electronic resistivity leap increases several magnitudes ( times).Positive temperature coefficient the (PTC) acts according to this nature manufacture.After in semiconductor multi-crystal grain structure BaTio3, its crystal grain (general size small is approximately 3-10 µ m) the interior is the semiconductor nature; But the crystal boundary (has f e r r o electricity) for the high-resistance area. When type crystal external voltage, voltage majority of landings on high-resistance crystal boundary level, thus the crystal boundary has an effect to the material electric conductivity .The electron must pass through the crystal boundary barrier potential barrier from a crystal grain to be able to arrive another crystal grain .Below Curie temperature T c, BaTio3 is tetragonal system dielectric, the existence has the spontaneous polarized very strong internal electric field, enable the electron to have the high energy, thus the traversing crystal boundarypotential barrier is easy. But above Curie temperature T c, BaTio3 becomes the cubic system by the tetragonal system, polarizes vanishing spontaneously, internal electric field vanishing, the electricity is difficult in the traversing potential barrier, therefore above curie warm waste T c, electronic resistivity sharp increase. When two crystal grains contact mutually, crystal grain barrier potential barrier as shown in Figure is potential barrier le vel thickness, ø0 is the barrier height .According to the equation, the barrier height ø0 sticks the effective dielectric constant εe ff between with the crystal the relations is: In the formula, n0 is the density of donors; e is t he electronic electric quantity .ε0 is the vacuum coefficient of d i electrical loss. When the electronic overstepping potential barrier enters ø0, the electronic resistivity may write isWhen the temperature is l ower than Curie temperature TC, εe ff the value is approximately about 104, therefore ø0 very small, the ceramic electronic resistivity rho approaches in the volume resistivity ρv, after the temperature surpasses Curie temperature TC, the value drops suddenly, the A value increases, causes rho the value sharp increase, dopes BaTio3 and rho and between the temperature relational like chart .NTC t h r principle of work NTC the r s tor majority is by the transition family metal oxide compound (mainly is with M n, co, Ni, Fe and so on), the agglutination forms the semiconductor metal oxide compound under the controlled condition, they only have the P semiconductor characteristic .Regarding the common semiconducting material, the electronic resistivity mainly is relies on along with the warm waste change the current carrier number along with the temperature change, the temperature increment, the current carrier number increases, electric conduction ability enhancement. Thus electronic resistivity F falls. Regarding transition metal oxide compound semiconductor, for example Ni O, because its acceptor ionizing energy is very small, broad basic ionized completely in the room temperature, namely the current carrier density basically has nothing to do with the temperature, this time, should mainly consider the transport ratio and the temperature relations .By the semiconductor physics knowledge, the transport ratio expresses by the equation below:In the formula: The d-- oxygen octahedron gap is away from (Ni O is the Na Cl structure); V0-- lattice vibration frequency; The Ei-- activation energy, indicated the electron jumps originally from one in the position the energy which needs to the neighboring atom site. Or rewriting Then the electronic resistivity is: 0Ne-Ei/kT If command, then type changes: rho =ρ0eEi/KT Obviously the metal oxide compound semiconductor electronic resistivity mainly has the transport ratio along with the temperature change to cause along with the temperature change .When temperature increment, the electronic resistivity drops, assumes the negative temperature coefficient characteristic. Critical temperature also belongs to the negative temperature coefficient. But in some critical temperature scope, its resistance number drops suddenly along with the temperature rise .Anti- as shown in Figure 4-4. In the chart the anti- r curve has aresistance number point of discontinuity, approximately for 68℃, resistance number point of discontinuity magnitude generally in 3~ carry on the adjustment based on the material ingredient, it is suitable specially in 65℃~75℃ between uses, this kind of resistor may make the constant temperature control and on-off element.The CTR r usually uses the glass semiconductor processing, take the vanadium as the main material. Mixes in certain materials and so on oxide compound like C a O, B a O, S O or P2O5, TiO2 becomes after the hot dissolve. temperature sensor basic characteristic in view of the fact that the temperature sensor type is many, moreover its work mechanism is also different. This mainly introduces t the hot sensitive diode and the hot sensitive transistor characteristic and the parameter. from the s the material and anti- and so on carry on the classification variously. According to structure shape classification: Laminated shape, gasket shape, rod-shaped, tubular, thin membrane, thick membranous and other shapes. Includes according to the anti- temperature ra classification: Normal temperature, high temperature and ultralow temperature hot sensitive resistor. Includes according to the anti- classification: Negative temperature coefficient r (NTC), switch temperature r (PTC); Slow aberration positive temperature coefficient r (PTC), the critical negative temperature coefficient, the platinum resistor limits the temperature curve like chart 4-4 curvature 1. 1st, resistance - temperature characteristic anti- is refers to between the actual resistance value and the resistance body temperature dependent relations, this is one of basic characteristics.PTC switch positive temperature coefficient anti- curve. value rises suddenly to some temperature nearby the maximizing.Through the doping .If dopes P b in BaTio3, may cause Tc to the high temperature traverse, mixes in elements and so on S r or S n after BaTio3, may cause TC to the low temperature traverse. May according to need to adjust t Curie temperature TC. The actual resistance number expressed with RT. Is under certain ambient temperature, uses causes the resistance number change not to surpass the resistance value which % survey power actual resistance value is called the zero energy resistance value, or is called does not give off heat the power resistance value (cold resistance value).The actual resistance value size is decided by the resistor material and the geometry shape. If the actual resistance number own temperature has the following relations: NTC In the formula: RT time 11 temperature T actual resistance value; R 1 and resistance geometry shape with material related constant B, A 11 material constants. For the easy to operate, usually takes the ambient temperature for 25℃ to take the reference temperature, then has: NTC puts the resistor hotly: RT/R25=exp[B(1/T-1/298)] PTC g change along with the temperatureT change, and is proportional with material constant B. Therefore, usually while gives the resistance temperature coefficient, must point out when the survey temperature, positive temperature coefficient t a T in value superior constant A. Slow aberration positive temperature coefficient value in %/℃ 110%/℃ between. But the switch(mutant) positive temperature co efficient T may achieve 60%/℃ or higher. Material constant B is uses for to describe the t material physical property - parameter. Also is called the thermal sensitivity target. In the operating region, the B value is not a strict constant, has slightly along with the temperature ascension increases .In general, the B value great electronic resistivity is also high. The different B value material has the different use, like ordinary negative temperature coefficient material constant B value between 2000yi5000 K. The negative temperature coefficient B value may according to the equation below computation: Positive temperature coefficient resistor, its A value according to equation below computation: In the formula, R1 R2 respectively is time thermodynamic temperature T1 and the T2 resistance value. 2. thermal properties (1) dissipation constant H dissipation constant H defined as the temperature each increase once diffusion power .It uses for when describes work, the resistance element and the external environment carry on the hot conversation a physical quantity. Dissipation constant H and dissipated power P .The temperature increment AT relations are The H size and the t structure, locates the environment medium type, the velocity of movement, the pressure and the heat conduction performance and so on related, when ambient temperature change, H has the change. (2) capacity and the time-constant r appliance has certain calorific capacity C, therefore it has certain warm. Also is the temperature change needs certain time. When the is heated up the T2 temperature, puts to the temperature is in the T0 environment, does not add the electric power, the starts to decrease temperature, its temperature T is the time t function, in △t time. The may indicate to the environment diffusion quantity of heat is: H(T-T0)△t, this part of quantity of heat is provides by the temperature decrease. Its value for - C△T, therefore has:Expressed in the environment atmosphere the steam content physical quantity is a y. The humidity expression method has two kinds, namely absolute humidity and relative h um (RH).The absolute humidity is refers to in the atmosphere the water content absolute value, the relative humidity is refers to in the atmosphere the steam to press with the identical temperature under ratio of the saturated steam tension, expressed with the percentage. The humidity sensor or the dew cell are refer to the paraphrase to the humidity sensitive part, it may be the wet sensitive resistor, also may be the wet sensitive capacitor or other dew cells. The humidity sensor classification classifies according to the feeling wet physical quantity, the humidity sensor may divide into three big kinds, namely wet sensitive resistor, wet sensitive capacitor and wet sensitive transistor. The humidity resistor makes which according to the use different material may divide into: Metal oxide compound semiconductor ceramics wet sensitive resistor, for example: MgCr2O4 series, ZnO-Cr2O3 series; Element material wet sensitive resistor, for example: Semiconductor G e, Si, Se and C element; Compound wet sensitive resistor, for example: Li Cl, CaSO4, and fluoride and iodide and so on; High polymer wet sensitive resistor and so on. The wet sensitive capacitor mainly is the porous Al2O3material makes as the medium. The wet sensitive transistor divides into the wet sensitive diode and the wet sensitive three levels of tubes. The wet sensitive resistor principle of work and the characteristic 1, the metal oxide compound semiconductor ceramics wet sensitive resistor (1) principle of work porous metal oxide compound semiconductor ceramics, in the crystal plane and the crystal boundary place, very easy to adsorb t drone. Because the water is one strong polar dielectric medium, nearby the h y drone hydrogen atom has the very strong electric field, has the very big electron affinity. When h y drone adheres to stick cohere when the semiconductor ceramics surface, will form the energy level very deep attachment surface acceptor condition, but from semiconductor ceramics surface capture electron, but will form the bound state in the ceramic surface the negative space charge, correspondingly will appear the hole in the near surface layer to accumulate, thus will cause the semiconductor ceramics electronic resistivity depression.Moreover, according to the ion electric conductance principle, the structure not compact semiconductor ceramics crystal grain has certain crevice, reveals the porous capillarity tubular .The drone may adsorbs through this kind of pore between various crystal grains surface and the crystal grain, because adsorbs the e separable relieves the massive electric conduction ion, these ions are playing the electric charge transportation role in the water adsorbed layer. along with humidity increase, material electronic resistivity drop. oxide compound semiconductor ceramics wet sensitive resistor principal variety and structure The metal oxide compound semiconductor ceramics wet sensitive resistor typical product includes: MgCr2O4 - TiO2 wet sensitive resistor, ZnO-Cr2O3 wet sensitive resistor, ZnO-Li2O3-V2O5 wet sensitive resistor and so on. For example: The ZnO-Li2O3-V2O5 wet sensitive resistance, is take Zn O as the main material, is joining a price, two prices, three prices and so on other metal oxide compound burns the ceramics semiconducting material, the survey humidity scope is 5%~100%RH, the measuring accuracy is 2%, is one kind of more ideal dew cell, and may make the miniaturization, the structure is simple. 2nd, element material wet sensitive resistor kind of wet sensitive resistor is a part which the element semiconducting material or the element material make.The carbon wet sensitive resistor is one resistance - humidity characteristic is the dew cell. With the organic matter polypropylene plastic piece or the stick are substrates, spreads cloth one to include the conductive carbon granule organic textile fiber constitution. This kind of wet sensitive resistor craft is simple, is advantageous for the uses the organic material absorption of moisture, the volume expansion, between the carbon granule distance increases, thus the resistance value increases principle. The element semiconductor, have on the honeycomb electrode ceramic substrate, is composed [granule diameter by the characteristic in the Fe3O4 colloid by the particle approximately for (100~250)×10-8m], each pellet only then a magnetic domain, therefore, the co current pellet attracts the union mutually, thus does not need the highpolymer material to make the colloid bond, but can obtain the good performance and the long service life. Figure 4-1 is the Fe3O4 colloid wet sensitive resistor structure drawing. Figure 4-2 is the Fe3O4 wet sensitive resistor resistance humidity characteristic curve, displays for the negative feeling wet characteristic. 4th, the wet sensitive resistor characteristic (1) resistance - humidity characteristic wet sensitive resistor resistance number along with the humidity change is generally the index relations change.温度传感器在种类繁多的传感器中,温度传感器在其产量和应用两方面都是数一数二的。
AD集成库部分元件中英文对照
AD集成库元件简写中英文对照表序号英文简写元件英文名元件中文名1 Res semi Semiconductor Resistor 半导体电阻2 Cap semi Semiconductor Capacitor 半导体电容器3 Cap Var Variable or Adjustable Capacitor 可变或可调电容4 Cap Pol1 Polarized Capacitor (Radial) 极化电容(径向)5 Cap Pol2 Polarized Capacitor (Axial) 极化电容(轴向)6 Cap Capacitor 电容(径向)7 Cap Pol3 Polarized Capacitor (Surface Mount) 极化电容(表面贴装)8 Cap Feed Feed-Through Capacitor 馈通电容9 Cap2 Capacitor 电容10 ResVaristorVaristor (Voltage-Sensitive Resistor) 压敏电阻(电压敏感电阻)11 Res Tap Tapped Resistor 抽头电阻12 Res Thermal Thermal Resistor 热敏电阻13 Rpot Potentiometer Resistor (侧调或顶调)电位器14 Rpot SM Square Trimming Potentiometer (顶调)方形电位器15 Res Bridge Resistor Bridge 电阻桥16 Bridge1 Full Wave Diode Bridge 整流桥17 Bridge2 Bridge Rectifier 整流桥集成组件(比1封装较大)18 Res Adj Variable Resistor 可变电阻19 Res3 Resistor IPC的高密度贴片电阻20 D Tunnel2 Tunnel Diode - Dependent Source Model 隧道二极管- 依赖源模型21 D Varactor Variable Capacitance Diode 变容二极管22 DSchottkySchottky Diode 肖特基二极管23 Diode 1N5402 3 Amp General Purpose Rectifier3放大器通用整流器其中电容,cap/cap2/cap pol1/cap pol2 的符号分别如下所示:。
TypesofSensors(各种类型的传感器)外文翻译
Types of SensorsⅠ.Pressure sensorsModel FDS05-P Diffused Silicon Pressure Sensor: Tee intelligent industrial pressure sensor adopts the imported sensor of high quality. with great defending grade,it can work in any caustic condition. By linking external , linking external canola,it can measure the temperature of the medium with high temperature. It is stable and capable of limiting current in positive direction and protecting in negative direction. It is with the ability of intelligent temperature and linearity compensation with the temperature of一40℃~+ 140℃.It is widely used in petrifaction ,metallurgy, electric power and light spinning.Ⅱ.Load cell &torque sensorsSuspended arm type Bx5: Its elastomeric adopts cutting (or curved) hanging girder configuration, so it is low in height and with high configuration intensity. It is good against fatigue and eccentricity. It is stable and reliable in product performances,high in precision, and convenient in mount-up and use. It is suitable for force measurement and weighting such as strap balance, chute balance, flat balance and ground balance .Loading type: pull ox push .Ⅲ.Temp& hum sensorsMote MSTB Temperature Transducer: A sensor module is fitted in the temperature trans-ducker’s terminal block,which uses a specific chip to magnify and has linearization approach to improve the measurement precision .Tie cold junction needs no compensation. Sa it is with high direct load capacity , large transfer distance and strong ability of ants-external interference。
热电偶温度传感器中英文对照外文翻译文献
中英文对照外文翻译文献(文档含英文原文和中文翻译)外文翻译:Thermocouple Temperatur sensorIntroduction to ThermocouplesThe thermocouple is one of the simplest of all sensors. It consists of two wires of dissimilar metals joined near the measurement point. The output is a small voltage measured between the two wires.While appealingly simple in concept, the theory behind the thermocouple is subtle, the basics of which need to be understood for the most effective use of the sensor.Thermocouple theoryA thermocouple circuit has at least two junctions: the measurement junction and a reference junction. Typically, the reference junction is created where the two wires connect to the measuring device. This second junction it is really two junctions: one for each of the two wires, but because they are assumed to be at the same temperature (isothermal) they are considered as one (thermal) junction. It is the point where the metals change - from the thermocouple metals to what ever metals are used in the measuring device - typically copper.The output voltage is related to the temperature difference between the measurement and the reference junctions. This is phenomena is known as the Seebeck effect. (See the Thermocouple Calculator to get a feel for the magnitude of the Seebeck voltage). The Seebeck effect generates a small voltage along the length of a wire, and is greatest where the temperature gradient is greatest. If the circuit is of wire of identical material, then they will generate identical but opposite Seebeck voltages which will cancel. However, if the wire metals are different the Seebeck voltages will be different and will not cancel.In practice the Seebeck voltage is made up of two components: the Peltiervoltage generated at the junctions, plus the Thomson voltage generated in the wires by the temperature gradient.The Peltier voltage is proportional to the temperature of each junction while the Thomson voltage is proportional to the square of the temperature difference between the two junctions. It is the Thomson voltage that accounts for most of the observed voltage and non-linearity in thermocouple response.Each thermocouple type has its characteristic Seebeck voltage curve. The curve is dependent on the metals, their purity, their homogeneity and their crystal structure. In the case of alloys, the ratio of constituents and their distribution in the wire is also important. These potential inhomogeneous characteristics of metal are why thick wire thermocouples can be more accurate in high temperature applications, when the thermocouple metals and their impurities become more mobile by diffusion.The practical considerations of thermocouplesThe above theory of thermocouple operation has important practical implications that are well worth understanding:1. A third metal may be introduced into a thermocouple circuit and have no impact, provided that both ends are at the same temperature. This means that the thermocouple measurement junction may be soldered, brazed or welded without affecting the thermocouple's calibration, as long as there is no net temperature gradient along the third metal.Further, if the measuring circuit metal (usually copper) is different to that of the thermocouple, then provided the temperature of the two connecting terminals is the same and known, the reading will not be affected by the presence of copper.2. The thermocouple's output is generated by the temperature gradient along the wires and not at the junctions as is commonly believed. Therefore it is important that the quality of the wire be maintained where temperature gradients exists. Wire quality can be compromised by contamination from its operating environment and the insulating material. For temperatures below 400°C, contamination of insulated wires is generally not a problem. At temperatures above 1000°C, the choice of insulationand sheath materials, as well as the wire thickness, become critical to the calibration stability of the thermocouple.The fact that a thermocouple's output is not generated at the junction should redirect attention to other potential problem areas.3. The voltage generated by a thermocouple is a function of the temperature difference between the measurement and reference junctions. Traditionally the reference junction was held at 0°C by an ice bath:The ice bath is now considered impractical and is replace by a reference junction compensation arrangement. This can be accomplished by measuring the reference junction temperature with an alternate temperature sensor (typically an RTD or thermistor) and applying a correcting voltage to the measured thermocouple voltage before scaling to temperature.The correction can be done electrically in hardware or mathematically in software. The software method is preferred as it is universal to all thermocouple types (provided the characteristics are known) and it allows for the correction of the small non-linearity over the reference temperature range.4. The low-level output from thermocouples (typically 50mV full scale) requires that care be taken to avoid electrical interference from motors, power cable, transformers and radio signal pickup. Twisting the thermocouple wire pair (say 1 twist per 10 cm) can greatly reduce magnetic field pickup. Using shielded cable or running wires in metal conduit can reduce electric field pickup. The measuring device should provide signal filtering, either in hardware or by software, with strong rejection of the line frequency (50/60 Hz) and its harmonics.5. The operating environment of the thermocouple needs to be considered. Exposure to oxidizing or reducing atmospheres at high temperature can significantly degrade some thermocouples. Thermocouples containing rhodium (B,R and S types) are not suitable under neutron radiation.The advantages and disadvantages of thermocouplesBecause of their physical characteristics, thermocouples are the preferred methodof temperature measurement in many applications. They can be very rugged, are immune to shock and vibration, are useful over a wide temperature range, are simple to manufactured, require no excitation power, there is no self heating and they can be made very small. No other temperature sensor provides this degree of versatility.Thermocouples are wonderful sensors to experiment with because of their robustness, wide temperature range and unique properties.On the down side, the thermocouple produces a relative low output signal that is non-linear. These characteristics require a sensitive and stable measuring device that is able provide reference junction compensation and linearization.Also the low signal level demands that a higher level of care be taken when installing to minimise potential noise sources.The measuring hardware requires good noise rejection capability. Ground loops can be a problem with non-isolated systems, unless the common mode range and rejection is adequate.Types of thermocoupleAbout 13 'standard' thermocouple types are commonly used. Eight have been given an internationally recognised letter type designators. The letter type designator refers to the emf table, not the composition of the metals - so any thermocouple that matches the emf table within the defined tolerances may receive that table's letter designator.Some of the non-recognised thermocouples may excel in particular niche applications and have gained a degree of acceptance for this reason, as well as due to effective marketing by the alloy manufacturer. Some of these have been given letter type designators by their manufacturers that have been partially accepted by industry.Each thermocouple type has characteristics that can be matched to applications. Industry generally prefers K and N types because of their suitability to high temperatures, while others often prefer the T type due to its sensitivity, low cost and ease of use.A table of standard thermocouple types is presented below. The table also showsthe temperature range for extension grade wire in brackets.Accuracy of thermocouplesThermocouples will function over a wide temperature range - from near absolute zero to their melting point, however they are normally only characterized over their stable range. Thermocouple accuracy is a difficult subject due to a range of factors. In principal and in practice a thermocouple can achieve excellent results (that is, significantly better than the above table indicates) if calibrated, used well below its nominal upper temperature limit and if protected from harsh atmospheres. At higher temperatures it is often better to use a heavier gauge of wire in order to maintain stability (Wire Gauge below).As mentioned previously, the temperature and voltage scales were redefined in 1990. The eight main thermocouple types - B, E, J, K, N, R, S and T - were re-characterised in 1993 to reflect the scale changes. (See: NIST Monograph 175 for details). The remaining types: C, D, G, L, M, P and U appear to have been informally re-characterised.Try the thermocouple calculator. It allows you the determine the temperature by knowing the measured voltage and the reference junction temperature.Thermocouple wire gradesThere are different grades of thermocouple wire. The principal divisions are between measurement grades and extension grades. The measurement grade has the highest purity and should be used where the temperature gradient is significant. The standard measurement grade (Class 2) is most commonly used. Special measurement grades (Class 1) are available with accuracy about twice the standard measurement grades.The extension thermocouple wire grades are designed for connecting the thermocouple to the measuring device. The extension wire may be of different metals to the measurement grade, but are chosen to have a matching response over a much reduced temperature range - typically -40°C to 120°C. The reason for using extension wire is reduced cost - they can be 20% to 30% of the cost of equivalent measurementgrades. Further cost savings are possible by using thinnergauge extension wire and a lower temperature rated insulation.Note: When temperatures within the extension wire's rating are being measured, it is OK to use the extension wire for the entire circuit. This is frequently done with T type extension wire, which is accurate over the -60 to 100°C range.Thermocouple wire gaugeAt high temperatures, thermocouple wire can under go irreversible changes in the form of modified crystal structure, selective migration of alloy components and chemical changes originating from the surface metal reacting to the surrounding environment. With some types, mechanical stress and cycling can also induce changes.Increasing the diameter of the wire where it is exposed to the high temperatures can reduce the impact of these effects.The following table can be used as a very approximate guide to wire gauge:At these higher temperatures, the thermocouple wire should be protected as much as possible from hostile gases. Reducing or oxidizing gases can corrode some thermocouple wire very quickly. Remember, the purity of the thermocouple wire is most important where the temperature gradients are greatest. It is with this part of the thermocouple wiring where the most care must be taken.Other sources of wire contamination include the mineral packing material and the protective metal sheath. Metallic vapour diffusion can be significant problem at high temperatures. Platinum wires should only be used inside a nonmetallic sheath, such as high-purity alumna.Neutron radiation (as in a nuclear reactor) can have significant permanent impact on the thermocouple calibration. This is due to the transformation of metals to different elements.High temperature measurement is very difficult in some situations. In preference, use non-contact methods. However this is not always possible, as the site of temperature measurement is not always visible to these types of sensors.Colour coding of thermocouple wireThe colour coding of thermocouple wire is something of a nightmare! There are at least seven different standards. There are some inconsistencies between standards, which seem to have been designed to confuse. For example the colour red in the USA standard is always used for the negative lead, while in German and Japanese standards it is always the positive lead. The British, French and International standards avoid the use of red entirely!Thermocouple mountingThere are four common ways in which thermocouples are mounted with in a stainless steel or Inconel sheath and electrically insulated with mineral oxides. Each of the methods has its advantages and disadvantages.Sealed and Isolated from Sheath: Good relatively trouble-free arrangement. The principal reason for not using this arrangement for all applications is its sluggish response time - the typical time constant is 75 secondsSealed and Grounded to Sheath: Can cause ground loops and other noise injection, but provides a reasonable time constant (40 seconds) and a sealed enclosure.Exposed Bead: Faster response time constant (typically 15 seconds), but lacks mechanical and chemical protection, and electrical isolation from material being measured. The porous insulating mineral oxides must be sealedExposed Fast Response: Fastest response time constant, typically 2 seconds but with fine gauge of junction wire the time constant can be 10-100 ms. In addition to problems of the exposed bead type, the protruding and light construction makes the thermocouple more prone to physical damage.Thermocouple compensation and linearizationAs mentioned above, it is possible to provide reference junction compensation in hardware or in software. The principal is the same in both cases: adding a correction voltage to the thermocouple output voltage, proportional to the reference junction temperature. To this end, the connection point of the thermocouple wires to the measuring device (i.e. where the thermocouple materials change to the copper of thecircuit electronics) must be monitored by a sensor. This area must be design to be isothermal, so that the sensor accurately tracks both reference junction temperatures.The hardware solution is simple but not always as easy to implement as one might expect.The circuit needs to be designed for a specific thermocouple type and hence lacks the flexibility of the software approach.The software compensation technique simplifies the hardware requirement, by eliminating the reference sensor amplifier and summing circuit (although a multiplexer may be required).The software algorithm to process the signals needs to be carefully written. A sample algorithm details the process.A good resource for thermocouple emf tables and coefficients is at the US Commerce Dept's NIST web site. It covers the B, E, J, K, N, R, S and T types.The thermocouple as a heat pumpThe thermocouple can function in reverse. If a current is passed through a thermocouple circuit, one junction will cool and the other warm. This is known as the Peltier Effect and is used in small cooling systems. The effect can be demonstrated by alternately passing a current through a thermocouple circuit and then quickly measuring the circuit's Seebeck voltage. This process has been used, with very fine thermocouple wire (0.025 mm with about a 10 mA current), to measure humidity by ensuring the cooled junction drops below the air's dew point. This causes condensation to form on the cooled junction. The junction is allowed to return to ambient, with the temperature curve showing an inflection at the dew point caused by the latent heat of vaporization.Measuring temperature differencesThermocouples are excellent for measuring temperatures differences, such as the wet bulb depression in measuring humidity. Sensitivity can be enhanced by constructing a thermopile - a number of thermocouple circuits in series.In the above example, the thermopile output is proportional to the temperaturedifference T1 - T2, with a sensitivity three times that of a single junction pair. In practice, thermopiles with two to hundreds of junctions are used in radiometers, heat flux sensors, flow sensors and humidity sensors. The thermocouple materials can be in wire form, but also printed or etched as foils and even electroplated.An excellent example of the thermopile is in the heat flux sensors manufactured by Hukseflux Thermal Sensors. Also see RdF Corp. and Exergen Corp.The thermocouple is unique in its ability to directly measure a temperature difference. Other sensor types require a pair of closely matched sensors to ensure tracking over the entire operational temperature range.The thermoelectric generatorWhile the Seebeck voltage is very small (in the order of 10-70μV/°C), if the circuit's electrical resistance is low (thick, short wires), then large currents are possible (e.g. many amperes). An efficiency trade-off of electrical resistance (as small as possible) and thermal resistance (as large as possible) between the junctions is the major issue. Generally, electrical and thermal resistances trend together with different materials. The output voltage can be increased by wiring as a thermopile.The thermoelectric generator has found its best-known application as the power source in some spacecraft. A radioactive material, such as plutonium, generates heat and cooling is provided by heat radiation into space. Such an atomic power source can reliably provide many tens of watts of power for years. The fact that atomic generators are highly radioactive prevents their wider application.译文:热电偶温度传感器热电偶的定义热电偶是最简单的传感器之一。
智能红外传感器外文文献翻译中英文
外文文献翻译(含:英文原文及中文译文)文献出处:M G B r a y.Smart Infrared Sensors[J] International Journal of Computational Science & Engineering, 2015, 3(1 ):21-31 •英文原文Smart Infrared SensorsMG BrayKeeping up with continuously evolving process technologies is a major challenge for process engineers. Add to that the demands of staying current with rapidly evolving methods of monitoring and controlling those processes, and the assignment can become quite intimidating. However,infrared (IR) temperature sensor manufacturers are giving users the tools they need to meet these challenges: the latest computer-related hardware, software, and communications equipment, as well as leading-edge digital circuitry. Chief among these tools, though, is the next generation of IR thermometers —the smart sensor. Today^s new smart IR sensors represent a union of two rapidly evolving sciences that combine IR temperature measurement with high-speed digital technologies usually associated with the computer These instruments are called smart sensors because they incorporate microprocessors programmed to act as transceivers for bidirectional, serial communications between sensors onthe manufacturing floor and computers in the control room (see Photo 1).And because the circuitry is smaller,the sensors are smaller,simplifying installation in tight or awkward areas. Integrating smart sensors into new or existing process control systems offers an immediate advantage to process control engineers in terms of providing a new level of sophistication in temperature monitoring and controLIntegrating Smart Sensors into Process LinesWhile the widespread implementation of smart IR sensors is new, IR temperature measurement has been successful 1 y used in process monitoring and control for decades (see the sidebar,“How Infrared Temperature Sensors W o r k,‟‟below). In the past, if process engineers needed to change a sensor‟s settings,they would have to either shut down the line to remove the sensor or try to manually reset it in place. Either course could cause delays in the line,and,in some cases, be very dangerous. Upgrading a sensor usually required buying a new unit,calibrating it to the process, and installing it while the process line lay inactive. For example, some of the sensors in a wire galvanizing plant used to be mounted over vats of molten lead,zinc,and/or muriatic acid and accessible only by reaching out over the vats from a catwalk. In the interests of safety, the process line would have to be shut down for at least24 hours to cool before changing and upgrading a sensor.Today, process engineers can remotely configure, monitor,address,upgrade, and maintain their IR temperature sensors. Smart models with bidirectional RS-485 or RS-232 communications capabilities simplify integration into process control systems. Once a sensor is installed on a process line,engineers can tailor all its parameters to fit changing conditions—all from a PC in the control room. If, for example, the ambient temperature fluctuates, or the process itself undergoes changes in type, thickness, or temperature, all a process engineer needs to do is customize or restore saved settings at a computer terminal. If a smart sensor fails due to high ambient temperature conditions, a cut cable,or failed components, its fail-safe conditions engage automatically. The sensor activates an alarm to trigger a shutdown, preventing damage to product and machinery. If ovens or coolers fail, HI and LO alarms can also signal that there is a problem and/or shut down the line.Extending a Sensor‟s Useful LifeFor smart sensors to be compatible with thousands of different types of processes, they must be fully customizable. Because smart sensors contain EPROMs (erasable programmable read only memory), users can reprogram them to meet their specific process requirements using field calibration, diagnostics,and/or utility software from the sensor manufacturer.Another benefit of owning a smart sensor is that its firmware, the software embedded in its chips, can be upgraded via the communications link to revisions as they become available —without removing the sensor from the process line. Firmware upgrades extend the working life of a sensor and can actually make a smart sensor smarter.The Raytek Marathon Series is a full line of 1- and 2-color ratio IR thermometers that can be networked with up to 32 smart sensors. Available models include both integrated units and fiber-optic sensors with electronic enclosures that can be mounted away from high ambienttemperatures.Clicking on a sensor window displays the configuration settings for that particular sensor. The Windows graphical interface is intuitive and easy to use. In the configuration screen, process engineers can monitor current sensor settings, adjust them to meet their needs, or reset the sensor back to the factory defaults. All the displayed information comes from the sensor by way of the RS-485 or RS-232 serial connection.The first two columns are for user input. The third monitors the sensor‟s parameters in real time. Some parameters can be changed through other screens, custom programming, and direct PC-to-sensor commands. Parameters that can be changed by user input include the following:•Relay contact can be set to NO (normally open) or NC (normallyclosed).•Relay function can be set to alarm or setpoint.•Temperature units can be changed from degrees Celsius to degrees Fahrenheit,or vice versa. -Display and analog output mode can be changed for smart sensors that have combined one- and two-color capabilities-•Laser (if the sensor is equipped with laser aiming) can be turned on or off.•Milliamp output settings and range can be used as automaticprocess triggers or alarms.•Emissivity (for one-color) or slope (for two-color) ratio thermometers values can be set. Emissivity and slope values for common metal and nonmetal materials, and instructions on how to determine emissivity and slope, are usually included with sensors.•Signal processing defines the temperature parameters returned. Average returns an object‟s average temperature over a period of time; peak-hold returns an object‟s peak temperature either over a period of time or by an external trigger.•HI alarm/LO alarm can be set to warn of improper changes in temperature. On some process lines, this could be triggered by a break in a product or by malfunctioning heater or cooler elements-•Attenuation indicates alarm and shut down settings for two-color ratio smart sensors. In this example, if the lens is 95% obscured, an alarm warns that the temperature results might be losing accuracy (known as a “dirty window”alarm). More than 95% obscurity can trigger an automatic shutdown of the process-Using Smart SensorsSmart IR sensors can be used in any manufacturing process in which temperatures are crucial to high-quality product.Six IR temperature sensors can be seen monitoring producttemperatures before and after the various thermal processes and before and after drying. The smart sensors are configured on a high-speed multidrop network (defined below) and are individually addressable from the remote supervisory computer. Measured temperatures at all sensor locations can be polled individually or sequentially; the data can be graphed for easy monitoring or archived to document process temperature data. Using remote addressing features,set points, alarms, emissivity,and signal processing,information can be downloaded to each sensor. The result is tighter process control.Remote Online Addressability,smart sensors can In a continuous process similar to that in Figure 2be connected to one another or to other displays,chart recorders, and controllers on a single network. The sensors may be arranged in multidrop or point-to-point configurations, or simply stand alone.In a multidrop configuration, multiple sensors (up to 32 in some cases) can be combined on a network-type cable. Each can have its own ……address,”allowing it to be configured separately with different operating parameters- Because smart sensors use RS-485 or FSK (frequency shift keyed) communications, they can be located at considerable distances from the control room computer —up to 1200 m (4000 ft.) for RS-485, or 3000 m (10,000 ft.) for FSK. Some processes use RS-232communications, but cable length is limited to <100 ftIn a point-to-point installation, smart sensors can be connected to chart recorders,process controllers, and displays, as well as to the controlling computer In this type of installation, digital communications can be combined with milliamp current loops for a complete all-around process communications package. Sometimes,however,specialized processes require specialized software. A wallpaper manufacturer might need a series of sensors programmed to check for breaks and tears along the entire press and coating run,but each area has different ambient and surface temperatures, and each sensor must trigger an alarm if it notices irregularities in the surface. For customized processes such as this,engineers can write their own programs using published protocol data. These custom programs can remotely reconfigure sensors on the fly —without shutting down the process line.Field Calibration and Sensor UpgradesWhether using multidrop,point-to-point, or single sensor networks,process engineers need the proper software tools on their personal computers to calibrate, configure, monitor, and upgrade those sensors. Simple,easy-to-use data acquisition,configuration,and utility programs are usually part of the smart sensor package when purchased, or custom software can be usedWith field calibration software, smart sensors can be calibrated, new parameters downloaded directly to the sensor‟s circuitry,and the sensor‟s current parameters saved and stored as computer data files to ensure that a complete record of calibration and/or parameter changes is kept. One set of calibration techniques can include one-point offset and two- and three-point with variable temperatures:•One-point offset. If a single temperature is used in a particular process, and the sensor reading needs to be offset to make it match a known temperature, one-point offset calibration should be used. This offset will be applied to all temperatures throughout the entire temperature range. For example, if the known temperature along a float glass line is exactly 1800°F, the smart sensor, or series of sensors, can be calibrated to that temperature.•Two-point. If sensor readings must match at two specific temperatures, the two-point calibration shown in Figure 3 should be selected. This technique uses the calibration temperatures to calculate a gain and an offset that are applied to all temperatures throughout the entire range.•Three-point with variable temperature. If the process has a wide range of temperatures,and sensor readings need to match at three specific temperatures, the best choice is three-point variable temperaturecalibration (see Figure 4). This technique uses the calibration temperatures to calculate two gains and two offsets. The first gain and offset are applied to all temperatures below a midpoint temperature, and the second set to all temperatures above the midpoint. Three-point calibration is less common than one- and two-point, but occasionally manufacturers need to perform this technique to meet specific standards- Field calibration software also allows routine diagnostics, including power supply voltage and relay tests, to be run on smart sensors. The results let process engineers know if the sensors are performing at their optimum and make any necessary troubleshooting easier.ConclusionThe new generation of smart IR temperature sensors allows process engineers to keep up with changes brought on by newer manufacturing techniques and increases in production. They now can configure as many sensors as necessary for their specific process control needs and extend the life of those sensors far beyond that of earlier,“non -smart”designs. As production rates increase, equipment downtime must decrease. By being able to monitor equipment and fine-tune temperature variables without shutting down a process, engineers can keep the process efficientand the product quality high. A smart IR sensor\s digital processing components and communications capabilities provide a level of flexibility,safety, and ease of use not achieved until now.How Infrared Temperature Sensors WorkInfrared (IR) radiation is part of the electromagnetic spectrum,which includes radio waves,microwaves,visible light, and ultraviolet light, as well as gamma rays and X-rays. The IRrange falls between the visible portion of the spectrum and radio waves. IR wavelengths are usually expressed in microns,with the IR spectrum extending from 0.7 to 1000 microns. Only the 0.7-14 micron band is used for IR temperature measurement.Using advanced optic systems and detectors, noncontact IR thermometers can focus on nearly any portion or portions of the 0.7-14 micron band. Because every object (with the exception of a blackbody) emits an optimum amount of IR energy at a specific point along the IR band, each process may require unique sensor models with specific optics and detector types. For example, a sensor with a narrow spectral range centered at 3.43 microns is optimized for measuring the surface temperature of polyethylene and related materials- A sensor set up for 5 microns is used to measure glass surfaces. A 1 micron sensor is used for metals and foils. The broader spectral ranges are used to measure lower temperature surfaces, such as paper, board, poly, and foil composites.The intensity of an object's emitted IR energy increases or decreasesin proportion to its temperature. It is the emitted energy, measured as the t a rg e t‟s emissive,that indicates an object丨s temperature.Emissive is a term used to quantify the energy-emitting characteristics of different materials and surfaces. IR sensors have adjustable emissive settings, usually from 0.1 to 1.0, which allow accurate temperature measurements of several surface types.The emitted energy comes from an object and reaches the IR sensor through its optical system, which focuses the energy onto one or more photosensitive detectors. The detector then converts the IR energy into an electrical signal, which is in turn converted into a temperature value based on the sensor's calibration equation and the target's emissive. This temperature value can be displayed on the sensor, or, in the case of the smart sensor, converted to a digital output and displayed on a computer terminal。
sensor 翻译
sensor 翻译sensor 翻译为传感器,是一种能够感知和测量环境中各种物理量和信号的装置或设备。
传感器通常用于将物理量转换为电信号,然后通过电子电路进行处理和分析。
它广泛应用于各个领域,包括工业自动化、医疗、交通、农业等。
以下是一些常见的传感器及其用法和中英文对照例句:1. 温度传感器 (Temperature Sensor):用于测量环境或物体的温度。
- The temperature sensor accurately measures the room temperature. (温度传感器准确地测量室温。
)- The car's engine temperature sensor alerted the driver of overheating. (汽车引擎温度传感器提醒驾驶员发生过热。
)2. 光传感器(Light Sensor):用于检测光照强度或光线的存在与否。
- The light sensor automatically adjusts the screen brightness based on ambient light. (光传感器根据环境光自动调节屏幕亮度。
)- The security system's light sensor triggered the outdoor lights when it detected movement. (安全系统的光传感器在检测到运动时触发室外灯光。
)3. 压力传感器 (Pressure Sensor):用于测量物体或环境的压力。
- The pressure sensor in the car's tire warns the driver whenthe tire pressure is low. (汽车轮胎的压力传感器在轮胎压力过低时警告驾驶员。
)- The pressure sensor accurately measures the fluid pressure in the pipeline. (压力传感器准确测量管道中的流体压力。
电子信息工程专业一种新型的集成电路片上CMOS温度传感器毕业论文外文文献翻译及原文
毕业设计(论文)外文文献翻译文献、资料中文题目:一种新型的集成电路片上CMOS 温度传感器文献、资料英文题目:文献、资料来源:文献、资料发表(出版)日期:院(部):专业:电子信息工程班级:姓名:学号:指导教师:翻译日期: 2017.02.14普通本科毕业设计(论文)外文翻译文献题目一种新型的集成电路片上CMOS 温度传感器A Novel Built- in CMOS Temperature Sen sor for VLSICircuitsWang Nailong, Zhang Sheng and Zhou Runde( Institu te of M icroelectronics, T sing hua U niversity , B eij ing 100084, Ch ina)Abstract: A novel temperature sensor is developed and presented especially for the purpose of online the rmalmoni to ring of VLSI chips. This sensor requires very small silicon area and low power consumption, and the simulation results show that its accuracy is in the o rder of 018℃. The proposed sensor can be easily implemented using regular CMOS process techno logies, and can be easily integrated to any VLS I circuits to increase their reliability.Key words: temperature sensor; thermal testability; frequency output. EEACC: 1265A; 2560; 2570DCLC number: TN 47Document code: A Article ID: 025324177 (2004) 03202522051IntroductionDue to the advances in the fabricaion process field of in tegrated circu its, the component den sityand the overall power dissipat ion of the high per fo rmance VLSI chips increase cont inuously. At the beginning of this century, the power dissipated in asingle ch ip has exceeded 100W , and tightly packed chip assemblies as themultichip modules can even dissipate thou sandswatts. Therefore, the thermalstate of integrated circu its has been always a great prob lem concerned and is considered as a bottle neck in increasing the in tegrat ion of elect ron ic system s.To overcome this problem , many researchers developed low 2power design techn iques for VLS Isystems. In order to avoid thermal damages,continuous thermal monitoring should be appliedduring both the production reliability testing and the field operation. An eff icient way is to buildtemperatu resensors in to all VLSI chips, with theapp ropriate circuitry p roviding easy readout. Insome earlier works , the researchers used theparasitic, lateral or sub strate bipolartran sistors,which can be realized in mo st of the CMOS processes, as thermal sen so rs. These are u sually PTAT sensors. The weakness of these senors is that the bipolar structu resare not well characterized in a MOS process. Thus, although they canp rovide a sat isf iect solution for a given process, thecircu its can not be regarded as a general CMOS approach and can not be widely used.2Problem formulationThere are various temperature sensors suitable for the rmalstate verification of in tegrated circuit microstructures such as the rmoresistors, pnjunctions, and the exploitation of the weakinversion of MOS transistors. Our objective is to convert the temperature to an oscillat ing signal to make it compat ib le to digital circu it design method and facilitate the evaluat ion of the temperature sensed. A temperatu re sen so r based on a ringo scillator is introduced in Ref., this cell guarantees a accuracy of 3℃that is marginally accep table as a chiptem perature sensor but the silicon area required is rather big. AMOS temperature controlled oscilla to risused as asensor to monitor the thermal state of microelectronic structu res in Ref. How ever, this sensor requires about 10 to 15mW power to drive the thermal delay line and the dissipatertran sistor.To overcome these inconven iences, w e th inkthat the temperature sensors to be used as builtinun its for VLSI circuits online the rmalmoni to ring should meet some special requirements as follows:( 1 ) Nearly linearity in a temperatu rerange(usually 0~ 100℃) ;( 2 ) Low power consumption (no more than 1 mW ) ;( 3 ) Simple structure and small silicon area(usually no more than 40 transistors) ; ( 4 ) Easy read out results with favorably digital output signal (e. g. , the frequency of asquare wave which carries the temperature information) ;( 5 ) Easy (one point) calib rat ion;( 6 ) High accu racy ( in the order of 2℃ or less) ;( 7 ) Compat ib ility w ith the p resen t CMO Sp rocess;Con sidering the given requ irements, we present a new builtin temperatu resensor meeting all the above requirements3 Built- in thermal mon itor ing sensorOur new temperature sensoris a voltage controlled relaxation o scillato rbasedtemperature sensor shown in Fig. 1. The circuit consists of two parts, a voltageout put sensor and a relaxation oscillator.F ig. 1 Temperature sensor designed based on avoltage2cont ro lled relaxation oscillator3.1Voltage-output sen sorOur voltage output sensor circuit exploits the temperature dependence of the mosimportant parameter of the MOS transistor, namely, the thresh old voltage (V T ). The thresh old voltage has a negative temperature coeff icient as:V T (T ) = V T (T 0) + a (T - T 0) (1)where a is the temperature coeff icient with atypical value of - 118mVöK in CMOS 0135Lm 5V technology; V T (T 0 ) is the value of the th reshold voltage attemperatu re T0.As shown in Fig. 1, the voltage output sensor is a th reshold voltage reference cell. The pchannelt ransistors P1, P2 constitu teacurrent mirror. The current of transist or N1 is mirrored to tansistors N 2,N 3, and N 4. The vo ltage drop on these t ran sistors isfed back to the gate of N 1. Fo r easy calculat ing,we choose asame size of the transistors N 2,N 3, and N 4 (BN 2= BN 3= BN 4) , and we choose approp riatesize of the other transistors to ensure that the transisto rs P1, P2, N 1, N 2, N 3, and N4 are all in the state of saturation. Then the out put voltages of th is sen so r are in direct proportion to the thresh old voltage and linear with temperature and their values are:V H = V T (1 +2K P12K P12 - 3K N 12) = k1V T (2)V L = V T (1 +2K N 12K P12 - 3K N 12) = k2V T (3)where is determined by the ratio between the gatesizes of the nchannel t ransistor N 1 and N 2, and is the ratio of the gate sizes of the pchannel transistor P1 and P2.By adju st ing the sizes of the t ran sisto rs, w efound shou ld be b igger than threetimes of,when the transistors P1, P2, N 1, N 2, N 3, and N 4 are all in the state of saturat ion.The advantages of th is circuit arrangeme t arethe simplicity and the stable outpu t. A n important feature is that the output voltages of V H and V L arepractically independen t of the supply voltage (V DD ).3. 2Voltage-con trolled relaxa t ion osc illa torThe quick in terfacing of the analogue, current output sensor with the digital environmen t is not asimple task. To overcome this problem we usea voltage controlled relaxat ion oscillato r as the voltage frequency converter. The output signal of th isconverter is asquare w ave, the frequency of which carries the temperatu re info rmation. This frequency can be easily turned in to adigital number bycoun tingthe square wave pulses in a prescribedt ime window.As shown in F ig. 1, the curren t of the resisto rism irro red using thet ran sisto rs P3, P4, P5,N5,N6 to provide the same sou rce and sink current s to charge and discharge thecapacitor C. Assum ing thein it ial value of the f o sc is logic 0, then the t ran sistor P6 is on and the t ran sisto rN 7 is off cau sing the capacitor C to be charged using the source curren t I un t il V cexceeds the upper th resho ld V H. W hen th isoccu rs, the output latchtoggles and the logic valueof f o sc becomes logic 1, w hich in turn makes thet ran sistor P6 off and the tran sistor N 7 on. Th ismakes the capacitor C to be discharged by the sinkcu rren t until the capacit r voltage falls below alowerthreshold V L at w h ich t ime the en t ire cyclerepeats. N eglecting the delay of the comparators,latch and transistors P6 and N 7, the oscillation cycle time should be:As the current is small and the W öL rat io of the transistor P3 is chosen to be big in this design,the V gsp can be appro ximated to the th reshold voltage of the transistor P1 and therefo e the currentcan be approximated byAnd the temperature dependence of the resistor R s iswhere k is the temperatu re coeficien t of the resistor,with typical value k= 255×10- 6ö℃fo r polysilicon sheet resistor in the CMOS 0135Lm 5V technology.Therefore, the oscillation cycle time is foundto beThis equation implies that the cycle t ime ofthe relaxation oscillator is nearly linear with temperature, and then the f requency of the o scillator is4Simulation results and discuss ionThe simulation result of the voltage output the rmalsen sorisillustrated in F ig. 2, and the varia ion of the relaxat ion oscillator based sensor oscillation cycle t ime and f requency versus the ch iptemperatu re is shown in Fig. 3.To evaluate a buildin thermal sensor, thereare three important characterist ics: accu racy, sili2con area ( transistor number ) , and powerdissipation. The characterist ics of our voltage cont rolled relaxation oscillator based sensor is shown in Table 1:5ConclusionIn this paper, apractical and efficient built intemperatu resensor for thermalmonito ring of the integrated circuits is in troduced. The main advantages of the presented chip temperature sensors are low silicon area, low power dissipation, digital output inform of oscillation frequency, high accuracy,and easily implemented using regular CMOS process techno logies. Therefore, this sensor can beeasily in tegrated to any VLS I circu it s to increasecircu it sreliab ility.References[ 1 ]Chandrakasan A , ShengS, Broderson R. Low 2power CMOS digital design. IEEE J So lid2State Circuits, 1992, 27 (4) : 473[ 2 ]NebelW , Mermet J. Low power design in deep subm icronelectronics. Boston: Kluwer A cadem ic Publishers, 1997,Chap ter 4. 1[ 3 ]Montane E,Bo ta S A , Sam itier J. A compact temperature sen2so r of a 110Lm CMOStechno logy using lateral PN P transis to rs. In: P roc THERM IN IC’96Wo rk shop, 1996: 45[ 4 ]Bianch i R A , Karam J M , Courto is B. CMOS compatible tem2perature senso r based on the lateral bipo lar transisto r fo rvery w ide temperature range app lications. Senso rs andA ctua2to rs A: Physical, 1998, 71 (1ö2) : 3[ 5 ] Quenot G M , Paris N. A temperature and voltage measurement cell for VLSI circuits. In: Euro2A sic’91, 1991: 334[ 6 ]SzekelyV , RenczM. Thermal test andmonito ring. Proceeding of the European Design and Test Conference, 1995: 601[ 7 ] A rabi K, Kam inska B. Built2in temperature senso rs fo r online thermal monito ringof m icroelectronic structures. IEEEInternational Conference on Computer Design, 1997:[ 8 ]BoschB. A thermal o scillato rusing the thermoelectronic ( seeback) effect in silicon. Solid2State Electron, 1976, 12: 372[ 9 ]Szekely V ,M arta C, Kohari Z, etal. CMOS sensors for online thermal monito ring of VL S I circuits. IEEE T rans VLSISyst, 1997, 5 (3) : 270[ 10 ]Huang Yip ing, Zhu Shiyang, LiAizhen, et al. High temperature pressuresensor fabricated with smartcut SO Imaterials.Chinese Journal of Sem iconductors, 2001, 22 (7) : 924 ( in Chinese)一种新型的集成电路片上CMOS 温度传感器摘要: 介绍了一种可以用于片上温度监控的CMO S 温度传感器, 该传感器具有面积小、功耗低、精度高、易于实现等优点, 可以比较容易地集成到芯片上实现温度监测功能.关键词: 温度传感器; 热可测性; 频率输出EEACC: 1265A; 2560; 2570D中图分类号: TN 47文献标识码: A文章编号: 025324177 (2004) 03202522051引言由于集成电路制造工艺领域的先进性,该组件密度和高表现所整体功耗超大规模集成电路芯片不断增加。
传感器英文翻译
1、Accelerometer Principles67 ratings | 4.01 out of 5| Print DocumentOverviewThis tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples. There are several physical processes that can be used to develop a sensor to measure acceleration. In applications that involve flight, such as aircraft and satellites, accelerometers are based on properties of rotating masses. In the industrial world, however, the most common design is based on a combination of Newton's law of mass acceleration and Hooke's law of spring action.Table of Contents1.Spring-Mass System2.Natural Frequency and Damping3.Vibration Effects4.Relevant NI Products5.Buy the BookSpring-Mass SystemNewton's law simply states that if a mass, m, is undergoing an acceleration, a, then there must be a force F acting on the mass and given by F = ma. Hooke's law states that if a spring of spring constant k is stretched (extended) from its equilibrium position for a distance D x, then there must be a force acting on the spring given by F = kDx.FIGURE 5.23 The basic spring-mass system accelerometer.In Figure 5.23a we have a mass that is free to slide on a base. The mass is connected to the base by a spring that is in its unextended state and exerts no force on the mass. In Figure 5.23b, the whole assembly is accelerated to the left, as shown. Now the spring extends in order to provide the force necessary to accelerate the mass. This condition is described by equating Newton's and Hooke's laws:ma = kDx(5.25)where k = spring constant in N/mDx = spring extension in mm = mass in kga= acceleration in m/s2Equation (5.25) allows the measurement of acceleration to be reduced to a measurement of spring extension (linear displacement) becauseIf the acceleration is reversed, the same physical argument would apply, except that the spring is compressed instead of extended. Equation (5.26) still describes the relationship between spring displacement and acceleration.The spring-mass principle applies to many common accelerometer designs. The mass that converts the acceleration to spring displacement is referred to as the test mass or seismic mass. We see, then, that acceleration measurement reduces to linear displacement measurement; most designs differ in how this displacement measurement is made.Natural Frequency and DampingOn closer examination of the simple principle just described, we findanother characteristic of spring-mass systems that complicates the analysis. In particular, a system consisting of a spring and attached mass always exhibits oscillations at some characteristic natural frequency. Experience tells us that if we pull a mass back and then release it (in the absence of acceleration), it will be pulled back by the spring, overshoot the equilibrium, and oscillate back and forth. Only friction associated with the mass and base eventually brings the mass to rest. Any displacement measuring system will respond to this oscillation as if an actual acceleration occurs. This natural frequency is given bywhere f N= natural frequency in Hzk = spring constant in N/mm = seismic mass in kgThe friction that eventually brings the mass to rest is defined by a damping coefficient , which has the units of s-1. In general, the effect of oscillation is called transient response, described by a periodic damped signal, as shown in Figure 5.24, whose equation isX T (t) = Xoe-µt sin(2p f N t) (5.28)where Xr(t) = transient mass positionXo= peak position, initiallyµ = damping coefficientfN= natural frequencyThe parameters, natural frequency, and damping coefficient in Equation (5.28) have a profound effect on the application of accelerometers.Vibration EffectsThe effect of natural frequency and damping on the behavior of spring-mass accelerometers is best described in terms of an applied vibration. If the spring-mass system is exposed to a vibration, then the resultant acceleration of the base is given by Equation (5.23)a(t) = -w2xosin wtIf this is used in Equation (5.25), we can show that the mass motion is given bywhere all terms were previously denned and w= 2p f, with/the applied frequency.FIGURE 5.24 A spring-mass system exhibits a natural oscillation with damping as response to an impulse input.FIGURE 5.25 A spring-mass accelerometer has been attached to a table which is exhibiting vibration. The table peak motion is xand the mass motionois D x.To make the predictions of Equation (5.29) clear, consider the situation presented in Figure 5.25. Our model spring-mass accelerometer has been fixed to a table that is vibrating. The x o in Equation (5.29) is the peak amplitude of the table vibration, and Dx is the vibration of the seismic mass within the accelerometer. Thus, Equation (5.29) predicts that the seismic-mass vibration peak amplitude varies as the vibration frequency squared, but linearly with the table-vibration amplitude. However, this result was obtained without consideration of the spring-mass system natural vibration. When this is taken into account, something quite different occurs.Figure 5.26a shows the actual seismic-mass vibration peak amplitude versus table-vibration frequency compared with the simple frequency squared prediction.You can see that there is a resonance effect when the table frequency equals the natural frequency of the accelerometer, that is, the value of Dx goes through a peak. The amplitude of the resonant peak is determined by the amount of damping. The seismic-mass vibration is described by Equation (5.29) only up to about f N/2.5.Figure 5.26b shows two effects. The first is that the actual seismic-mass motion is limited by the physical size of the accelerometer. It will hit"stops" built into the assembly that limit its motion during resonance. The figure also shows that for frequencies well above the natural frequency, the motion of the mass is proportional to the table peak motion, , but not to the frequency. Thus, it has become a displacement sensor. xoTo summarize:1. f < f N- For an applied frequency less than the natural frequency, the natural frequency has little effect on the basic spring-mass response given by Equations (5.25) and (5.29). A rule of thumb states that a safe maximum applied frequency is f < 1/2.5f N.-For an applied frequency much larger than the natural frequency, 2. f > fNthe accelerometer output is independent of the applied frequency. As shown in Figure 5.26b, the accelerometer becomes a measure of vibration displacement xof Equation (5.20) under these circumstances. It isointeresting to note that the seismic mass is stationary in space in this case, and the housing, which is driven by the vibration, moves about the mass. A general rule sets f > 2.5 f N for this case.Generally, accelerometers are not used near the resonance at their natural frequency because of high nonlinearities in output.FIGURE 5.26 In (a) the actual response of a spring-mass system to vibration is compared to the simple w2prediction In (b) the effect of various table peak motion is shownEXAMPLE 5.14An accelerometer has a seismic mass of 0.05 kg and a spring constant of 3.0 X 103N/m Maximum mass displacement is ±0 02 m (before the mass hits the stops). Calculate (a) the maximum measurable acceleration in g, and (b) the natural frequency.SolutionWe find the maximum acceleration when the maximum displacement occurs, from Equation (5.26).a.or becauseb. The natural frequency is given by Equation (5.27).2、Measuring Pressure with Pressure Sensors79 ratings | 4.00 out of 5| Print DocumentOverviewThis tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples. This tutorial introduces and explains the concepts and techniques of measuring pressure with pressure sensors.For more information, return to the NI Measurement Fundamentals Main Page. Table of Contents1.What is Pressure?2.The Pressure Sensor3.Pressure Measurement4.Signal Conditioning for Pressure Sensors5.DAQ Systems for Pressure Measurements6.ReferencesWhat is Pressure?Pressure is defined as force per unit area that a fluid exerts on its surroundings.[1] For example, pressure, P, is a function of force, F, and area, A.P = F/AA container full of gas contains innumerable atoms and molecules that are constantly bouncing of its walls. The pressure would be the average force of these atoms and molecules on its walls per unit of area of the container. Moreover, pressure does not have to be measured along the wall of a container but rather can be measured as the force per unit area along any plane. Air pressure, for example, is a function of the weight of the air pushing down on Earth. Thus, as the altitude increases, pressure decreases. Similarly, as a scuba diver or submarine dives deeper into the ocean, the pressure increases.The SI unit for pressure is the Pascal (N/m2), but other common units of pressure include pounds per square inch (PSI), atmospheres (atm), bars, inches of mercury (in Hg), and millimeters of mercury (mm Hg).A pressure measurement can be described as either static or dynamic. The pressure in cases where no motion is occurring is referred to as static pressure. Examples of static pressure include the pressure of the air inside a balloon or water inside a basin. Often times, the motion of a fluid changes the force applied to its surroundings. Such a pressure measurement is known as dynamic pressure measurement. For example, the pressure inside a balloon or at the bottom of a water basin would change as air is let out of the balloon or as water is poured out of the basin.Head pressure(or pressure head) measures the static pressure of a liquid in a tank or a pipe. Head pressure, P, is a function solely on the height, h, of the liquid and weight density, w, of the liquid being measured as shown in Figure 1 below.Figure 1. Head Pressure MeasurementThe pressure on a scuba diver swimming in the ocean would be the diver's depth multiplied by weight of the ocean (64 pounds per cubic foot). A scuba diver diving 33 feet into the ocean would have 2112 pounds of water on every square foot of his body. The translates to 14.7 PSI. Interestingly enough, the atmospheric pressure of the air at sea level is also 14.7 PSI or 1 atm. Thus, 33 feet of water create as much pressure as 5 miles of air! The total pressure on a scuba diver 33 feet deep ocean would be the combined pressure caused by the weight of the air and the water and would be 29.4 PSI or 2 atm.A pressure measurement can further be described by the type of measurement being performed. There are three types of pressure measurements: absolute, gauge, and differential. Absolute pressure measurement is measured relative to a vacuum as showing in Figure 2 below. Often times, the abbreviations PAA (Pascals Absolute) or PSIA (Pounds per Square Inch Absolute) are use to describe absolute pressure.Figure 2. Absolute Pressure Sensor[3]Gauge pressure is measured relative to ambient atmospheric pressure asshown in Figure 3. Similar to absolute pressure, the abbreviations PAG (Pascals Gauge) or PSIA (Pounds per Square Inch Gauge) are use to describe gauge pressure.Figure 3.Gauge Pressure Sensor[3]Differential pressure is similar to gauge pressure, but instead of measuring relative to ambient atmospheric pressure, differential measurements are taken with respect to a specific reference pressure as shown in Figure 4. Also, the abbreviations PAD (Pascals Differential) or PSID (Pounds per Square Inch Differential) are use to describe differential pressure.Figure 4. Differential Pressure Sensor[3]The Pressure SensorBecause of the great variety of conditions, ranges, and materials for which pressure must be measured, there are many different types of pressure sensor designs. Often pressure can be converted to some intermediate form, such as displacement. The sensor then converts thisdisplacement into an electrical output such as voltage or current. The three most universal types of pressure transducers of this form are the strain gage, variable capacitance, and piezoelectric.Of all the pressure sensors, Wheatstone bridge (strain based) sensors are the most common, offering solutions that meet varying accuracy, size, ruggedness, and cost constraints. Bridge sensors are used for high and low pressure applications, and can measure absolute, gauge, or differential pressure. All bridge sensors make use of a strain gage and a diaphragm as seen in Figure 4.Figure 4. Cross Section of a Typical Strain Gage Pressure Sensor [3]When a change in pressure causes the diaphragm to deflect, a corresponding change in resistance is induced on the strain gauge, which can be measured by a Data Acquisition (DAQ) System. These strain gauge pressure transducers come in several different varieties: the bonded strain gauge, the sputtered strain gauge, and the semiconductor strain gauge.In the bonded strain gauge pressure sensor, a metal foil strain gauge is actually glued or bonded to the surface where strain is being measured. These bonded foil strain gauges (BFSG) have been the industry standard for years and are continually used because of their quick 1000 Hz responsetimes to changes in pressure as well as their large -452°F to -525°F operating temperature.Sputtered strain gauge manufacturers sputter deposit a layer of glass onto the diaphragm and then deposit a thing metal film strain gauge on to the transd ucer’s diaphragm. Sputtered strain gauge sensors actually from a molecular bond between the strain gauge element, the insulating later, and the sensing diaphragm. These gauges are most suitable for long-term use and harsh measurement conditions.Integrated circuit manufacturers have developed composite pressure sensors that are particularly easy to use. These devices commonly employ a semiconductor diaphragm onto which a semiconductor strain gauge and temperature-compensation sensor have been grown. Appropriate signal conditioning is included in integrated circuit form, providing a dc voltage or current linearly proportional to pressure over a specified range.The capacitance between two metals plates changes if the distance between these two plates changes. A variable capacitance pressure transducer, seen in Figure 5 below, measures the change in capacitance between a metal diaphragm and a fixed metal plate. These pressure transducers are generally very stable and linear, but are sensitive to high temperatures and are more complicated to setup than most pressure sensors.Figure 5. Capacitance Pressure Transducer [4]Piezoelectric pressure transducer, as shown in Figure 6, take advantage of the electrical properties of naturally occurring crystals such as quartz. These crystals generate an electrical charge when they are strained. Piezoelectric pressure sensors do not require an externalexcitation source and are very rugged. The sensors however, do require charge amplification circuitry and very susceptible to shock and vibration.Figure 6. Piezoelectric Pressure Transducer [4]A common cause of sensor failure in pressure measurement applications is dynamic impact, which results in sensor overload. A classic example of overloading a pressure sensor is known as the water hammer phenomenon. This occurs when a fast moving fluid is suddenly stopped by the closing of a valve. The fluid has momentum that is suddenly arrested, which causes a minute stretching of the vessel in which the fluid is constrained. This stretching generates a pressure spike that can damage a pressure sensor. To reduce the effects of “water hammer”, sensors are often mounted with a snubber between the sensor and the pressure line. A snubber is usually a mesh filter or sintered material that allows pressurized fluid through but does not allow large volumes of fluid through and therefore prevents pressure spikes in the event of water hammer. A snubber is a good choice to protect your sensor in certain applications, but in many tests the peak impact pressure is the region of interest. In such a case you would want to select a pressure sensor that does not include overprotection. [3]Pressure MeasurementAs described above, the natural output of a pressure transducer is a voltage. Most strain based pressure transducers will output a small mV voltage. This small signal requires several signal conditioning considerations that are discussed in the next section. Additionally, many pressure transducers will output a conditioned 0-5V signal or 4-20 mA current. Both of these outputs are linear across the working range of thetransducer. For example both 0 V and 4 mA correspond to a 0 pressure measurement. Similarly, 5 volts and 20 mA correspond to the Full Scale Capacity or the maximum pressure the transducer can measure. The 0-5V and 4-20 mA signals can easily be measured by National InstrumentsMulti-function Data Acquisition (DAQ) hardware.See Also:Data Acquistion (DAQ) HardwareSignal Conditioning for Pressure SensorsAs with any other bridge based sensor, there are several signal conditioning considerations. To ensure accurate bridge measurements, it is important to consider the following:∙Bridge completion∙Excitation∙Remote sensing∙Amplification∙Filtering∙Offset∙Shunt CalibrationEach of these considerations are addressed thoroughly in the Measuring Strain with Strain Gauges tutorial linked below.Once you have obtained a measurable voltage signal, that signal must be converted to actual units of pressure. Pressure sensors generally produce a linear response across their range of operation, so linearization is often unnecessary, but you will need some hardware or software to convert the voltage output of the sensor into a pressure measurement. The conversion formula you will use depends on the type of sensor you are using, and will be provided by the sensor manufacturer. A typical conversion formula will be a function of the excitation voltage, full scale capacity of the sensor, and a calibration factor.[+] Enlarge ImageFor example, a pressure trandsducer with a full scale capacity of 10,000 PSI and a calibration factor of 3mv/V and given an excitation voltage of 10V DC produces a measured voltage of 15 mV, the measured pressure would be 5000 PSI.After you have properly scaled your signal, it is necessary to obtain a proper rest position. Pressure sensors (whether absolute or gauge) have a certain level that is identified as the rest position, or reference position. The strain gauge should produce 0 volts at this position. Offset nulling circuitry adds or removes resistance from one of the legs of the strain gauge to achieve this "balanced" position. Offset nulling is critical to ensure the accuracy of your measurement and for best results should be performed in hardware rather than software.See Also:Measuring Strain with Strain GaugesDAQ Systems for Pressure MeasurementsUsing SCXI with Pressure MeasurementsNational Instruments SCXI is a signal conditioning system for PC-based data acquisition systems as shown in Figure 7. An SCXI system consists of a shielded chassis that houses a combination of signal conditioning input and output modules, which perform a variety of signal conditioning functions. You can connect many different types of sensors, including absolute and gauge pressure sensors, directly to SCXI modules. The SCXI system can operate as a front-end signal conditioning system for PC plug-in data acquisition (DAQ) devices (PCI and PCMCIA) or PXI DAQ modules.[+] Enlarge ImageFigure 7. A Typical National Instruments SCXI SystemSCXI offers an excellent solution for measuring pressure. The SCXI-1520 universal strain-gauge module is ideal for taking strain based pressure measurements. It provides 8 simultaneous sampled analog input channels each with bridge completion, programmable excitation (0-10 V), remote excitation sensing, programmable gain amplification (1-1000), a programmable 4-pole Butterworth filter (10 Hz, 100 Hz, 1 kHz, 10kHz), offset nulling, and shunt calibration. The SCXI-1314 terminal block provides screw terminals for easy connections to your sensors. Additionally, the SCXI-1314T includes a built-in TEDS reader for Class II bridge-based smart TEDS sensors.Recommended starter kit for Pressure SCXI DAQ System:1.SCXI-1600 DAQ module2.SCXI chassis3.SCXI-1520 modules and SCXI-1314/SCXI-1314T terminal blocks4.Refer to /sensors for recommended sensor vendorsFor a customized solution, see the SCXI Advisor linked below.Using SC Series DAQ with Strain Based Pressure SensorsFor high performance integrated DAQ and signal conditioning, the National Instruments PXI-4220 shown in Figure 8, part of the SC Series, provides an excellent measurement solution. SC Series DAQ offers up to 333 kS/s measurements with 16-bit resolution, and combines data acquisition and signal conditioning into one plug in board. The PXI-4220 is a 200 kS/s, 16 bit DAQ board with programmable excitation, gain, and 4-pole Butterworth filter. Each input channel of the PXI-4220 also includes a 9-pin D-Sub connector for easy connection to bridge sensors, and programmable shunt and null calibration circuitry. The PXI-4220 provides the perfect solution for dynamic pressure measurements with low channel counts.Figure 8. National Instruments PXI-4220Recommended starter kit for Pressure SC Series DAQ System:1.PXI chassis2.PXI embedded controller3.PXI-4220 modules4.Refer to /sensors for recommended sensor vendorsFor a customized solution, see the PXI advisor linked below.Using SCC with Strain Based Pressure SensorsNational Instruments SCC provides portable, modular signal conditioning for DAQ system as seen in Figure 9 below. The SCC series provides a great low channel count and low cost solution that directly interfaces to National Instruments M Series DAQ boards. SCC modules can condition a variety of analog I/O and digital I/O signals, including bridge sensors. SCC DAQ systems include an SC Series shielded carrier such as the SC-2345 or the SC-2350, SCC modules, a cable, and a DAQ device. The SC-2350 shielded carrier provides additional support for TEDS sensors.[+] Enlarge ImageFigure 9. National Instruments SCC Carrier and ModulesThe SCC-SG24 Load Cell Input module accepts up to two full-bridge inputs from load cells or pressure sensors. Each channel of the module includes an instrumentation amplifier, a 1.6 kHz lowpass filter, and a potentiometer for bridge offset nulling. Each SCC-SG24 module also includes a single 10 V excitation source.Recommended Starter Kit for Pressure SCC DAQ System:1.M Series DAQ board2.SC-2345/SC-2350 module carrier3.SCC-SG24 modules (1 per 2 pressure sensors)4.Refer to /sensors for recommended sensor vendorsSee Also:Sensors - Affiliated Product AdvisorsSCXI Product AdvisorPXI Product AdvisorReferences[1] Johnson, Curtis D, “Pressure Principles” Process Control Instrumentation Technology, Prentice Hall PTB.[2] , “Strain Gauge Pressure Transducers”,/products/trans/t-presstrans.htm (current November 2003).[3] , “Honeywell Sensotec Frequently Asked Questions”, /pdf/FAQ_092003.pdf (current November 2003). [4] , "Pressure Measurement: Principles and Practice", /articles/0103/19/main.shtm l (current January 2003).3、Measuring Strain with Strain Gauges896 ratings | 4.27 out of 5| Print DocumentOverviewThis tutorial is part of the National Instruments Measurement Fundamentals series. Each tutorial in this series will teach you a specific topic of common measurement applications by explaining theoretical concepts and providing practical examples.This tutorial introduces and explains the concepts and techniques of measuring strain with strain gauges.You can also view an on demand webcast on strain gauge measurements. For more information, return to the NI Measurement Fundamentals Main Page. Table of Contents1.What Is Strain?2.The Strain Gauge3.Strain Gauge Measurement4.Signal Conditioning for Strain Gauges5.DAQ Systems for Strain Gauge Measurements6.Relevant NI ProductsWhat Is Strain?Strain is the amount of deformation of a body due to an applied force. More specifically, strain (e) is defined as the fractional change in length, as shown in Figure 1 below.Figure 1. Definition of StrainStrain can be positive (tensile) or negative (compressive). Although dimensionless, strain is sometimes expressed in units such as in./in. or mm/mm. In practice, the magnitude of measured strain is very small. Therefore, strain is often expressed as microstrain (me), which is e x 10-6.When a bar is strained with a uniaxial force, as in Figure 1, a phenomenon known as Poisson Strain causes the girth of the bar, D, to contract in the transverse, or perpendicular, direction. The magnitude of this transverse contraction is a material property indicated by its Poisson's Ratio. The Poisson's Ratio n of a material is defined as the negative ratio of the strain in the transverse direction (perpendicular to the force)/e. to the strain in the axial direction (parallel to the force), or n = eT Poisson's Ratio for steel, for example, ranges from 0.25 to 0.3.The Strain GaugeWhile there are several methods of measuring strain, the most common is with a strain gauge, a device whose electrical resistance varies in proportion to the amount of strain in the device. The most widely used gauge is the bonded metallic strain gauge.The metallic strain gauge consists of a very fine wire or, more commonly, metallic foil arranged in a grid pattern. The grid pattern maximizes the amount of metallic wire or foil subject to strain in the parallel direction (Figure 2). The cross sectional area of the grid is minimized to reduce the effect of shear strain and Poisson Strain. The grid is bonded to a thin backing, called the carrier, which is attached directly to the test specimen. Therefore, the strain experienced by the test specimen is transferred directly to the strain gauge, which responds with a linear change in electrical resistance. Strain gauges are available commercially with nominal resistance values from 30 to 3000 Ω, with 120, 350, and 1000 Ω being the most common values.Figure 2. Bonded Metallic Strain GaugeIt is very important that the strain gauge be properly mounted onto the test specimen so that the strain is accurately transferred from the test specimen, through the adhesive and strain gauge backing, to the foil itself.A fundamental parameter of the strain gauge is its sensitivity to strain, expressed quantitatively as the gauge factor (GF). Gauge factor is defined as the ratio of fractional change in electrical resistance to the fractional change in length (strain):The Gauge Factor for metallic strain gauges is typically around 2. Strain Gauge MeasurementIn practice, the strain measurements rarely involve quantities larger than a few millistrain(e x 10-3). Therefore, to measure the strain requires accurate measurement of very small changes in resistance. For example, suppose a test specimen undergoes a strain of 500 me. A strain gauge witha gauge factor of 2 will exhibit a change in electrical resistance of only2 (500 x 10-6) = 0.1%. For a 120 W gauge, this is a change of only 0.12 W.To measure such small changes in resistance, strain gauges are almost always used in a bridge configuration with a voltage excitation source. The general Wheatstone bridge, illustrated below, consists of four resistive arms with an excitation voltage, VEX, that is applied across the bridge.Figure 3. Wheatstone BridgeThe output voltage of the bridge, VO, will be equal to:From this equation, it is apparent that when R1/R2= R4/R3, the voltageoutput VOwill be zero. Under these conditions, the bridge is said to be balanced. Any change in resistance in any arm of the bridge will result in a nonzero output voltage.Therefore, if we replace R4in Figure 3 with an active strain gauge, any changes in the strain gauge resistance will unbalance the bridge and produce a nonzero output voltage. If the nominal resistance of the strain。
传感器 外文翻译 外文文献 英文文献 分布是温度传感器
Distributed Temperature SensorIn the human living environment, temperature playing an extremely important role。
No matter where you live, engaged in any work, ever-present dealt with temperature under. Since the 18th century, industry since the industrial revolution to whether can master send exhibition has the absolute temperature touch. In metallurgy, steel, petrochemical, cement, glass, medicine industry and so on, can say almost eighty percent of industrial departments have to consider the factors with temperature. Temperature for industrial so important, thus promoting the development of the temperature sensor.Major general through three sensor development phase: analog integrated temperature sensor. The sensor is taken with silicon semiconductor integrated workmanship, therefore also called silicon sensor or monolithic integrated temperature sensor. Such sensing instruments have single function (only measuring temperature), temperature measurement error is smaller, price low, fast response, the transmission distance, small volume, micro-consumption electronic etc, suitable for long distance measurement temperature, temperature control, do not need to undertake nonlinear calibration, peripheral circuit is simple. It is currently the most common application at home and abroad, an integrated sensor。
集成温度传感器(AD590)温度特性实验
集成温度传感器(AD590)温度特性实验一、实验目的:了解常用的集成温度传感器基本原理、性能与应用。
二、基本原理:集成温度传器将温敏晶体管与相应的辅助电路集成在同一芯片上,它能直接给出正比于绝对温度的理想线性输出,一般用于-50℃~+120℃之间温度测量。
集成温度传感器有电压型和电流型二种。
电流输出型集成温度传感器,在一定温度下,它相当于一个恒流源。
因此它具有不易受接触电阻、引线电阻、电压噪声的干扰。
具有很好的线性特性。
本实验采用的是AD590电流型集成温度传感器,其输出电流与绝对温度(T)成正比,它的灵敏度为1μA/K,所以只要串接一只取样电阻R(1k)即可实现电流1μA到电压1mV的转换组成最基本的绝对温度(T)测量电路(1mV/K)。
AD590工作电源为DC +4V~+30V,它具有良好的互换性和线性。
如图34—1为AD590测温特性实验原理图:图34—1 集成温度传器AD590测温特性实验原理图绝对温度(T)是国际实用温标也称绝对温标,用符号T表示,单位是K(开尔文)。
开氏温度和摄氏温度的分度值相同,即温度间隔1K等于1℃。
绝对温度T与摄氏温度t的关系是:T=273.16+t≈273+t ,显然,绝对零点即为摄氏零下273.16℃(t≈-273+T ℃)。
三、需用器件与单元:主机箱中的智能调节器单元、电压表、转速调节0~24V电源、±2V~±10V(步进可调)直流稳压电源;温度源、P t100热电阻(温度源温度控制传感器)、集成温度传器AD590(温度特性实验传感器);温度传感器实验模板。
四、实验步骤:1、测量室温值t0:将主机箱±2V~±10V(步进可调)直流稳压电源调节到±4V档,将电压表量程切换开关切到2V档。
按图34—2接线(不要用手抓捏AD590测温端),集成温度传器AD590放在桌面上。
检查接线无误后合上主机箱电源开关。
记录电压表显示值V i =273.16+t0,得t0≈V i-273 。
零部件英文缩写及零部件中英文对照
零部件英文缩写及零部件中英文对照一、零部件英文缩写1. PCB:Printed Circuit Board(印刷电路板)2. MCU:Microcontroller Unit(微控制器单元)3. IC:Integrated Circuit(集成电路)4. LED:Light Emitting Diode(发光二极管)5. LCD:Liquid Crystal Display(液晶显示器)6. motor:Electric Motor(电动机)7. sensor:Sensor(传感器)8. resistor:Resistor(电阻器)9. capacitor:Capacitor(电容器)10. inductor:Inductor(电感器)二、零部件中英文对照1. 集成电路:Integrated Circuit2. 发光二极管:Light Emitting Diode3. 液晶显示器:Liquid Crystal Display4. 电动机:Electric Motor5. 传感器:Sensor6. 电阻器:Resistor7. 电容器:Capacitor8. 电感器:Inductor9. 印刷电路板:Printed Circuit Board10. 微控制器单元:Microcontroller Unit三、更多零部件中英文对照11. 开关:Switch12. 连接器:Connector13. 插头:Plug14. 插座:Socket15. 线缆:Cable16. 变压器:Transformer17. 继电器:Relay18. 晶体管:Transistor19. 二极管:Diode20. 电池:Battery四、常用零部件英文缩写补充11. CPU:Central Processing Unit(中央处理单元)12. GPU:Graphics Processing Unit(图形处理单元)13. RAM:Random Access Memory(随机存取存储器)14. ROM:ReadOnly Memory(只读存储器)15. USB:Universal Serial Bus(通用串行总线)16. HDMI:HighDefinition Multimedia Interface(高清多媒体接口)17. VGA:Video Graphics Array(视频图形阵列)18. SATA:Serial ATA(串行高级技术附件)19. SSD:Solid State Drive(固态硬盘)20. HVAC:Heating, Ventilation, and Air Conditioning(供暖、通风及空调系统)五、扩展零部件中英文对照列表21. 振动电机:Vibration Motor22. 螺线管:Solenoid23. 伺服电机:Servo Motor24. 步进电机:Stepper Motor25. 保险丝:Fuse26. 断路器:Circuit Breaker27. 滑动轴承:Plain Bearing28. 滚动轴承:Ball Bearing29. 液压缸:Hydraulic Cylinder30. 气缸:Pneumatic Cylinder六、额外零部件英文缩写补充21. Liion:Lithiumion(锂离子)22. NiMH:NickelMetal Hydride(镍氢)23. OLED:Organic Light Emitting Diode(有机发光二极管)24. FPGA:FieldProgrammable Gate Array(现场可编程门阵列)25. DSP:Digital Signal Processor(数字信号处理器)26. GPS:Global Positioning System(全球定位系统)27. RFID:RadioFrequency Identification(射频识别)28. WiFi:Wireless Fidelity(无线保真)29. Bluetooth:蓝牙(一种无线技术标准)30. IoT:Internet of Things(物联网)。
传感器技术外文文献及中文翻译
Sensor technologyA sensor is a device which produces a signal in response to its detecting or measuring a property ,such as position , force , torque ,pressure , temperature ,humidity , speed ,acceleration ,or vibration 。
Traditionally ,sensors (such as actuators and switches )have been used to set limits on the performance of machines .Common examples are (a)stops on machine tools to restrict work table movements ,(b) pressure and temperature gages with automatics shut-off features ,and (c)governors on engines to prevent excessive speed of operation . Sensor technology has become an important aspect of manufacturing processes and systems 。
It is essential for proper data acquisition and for the monitoring ,communication ,and computer control of machines and systems 。
Because they convert one quantity to another , sensors often are referred to as transducers .Analog sensors produce a signal , such as voltage ,which is proportional to the measured quantity .Digital sensors have numeric or digital outputs that can be transferred to computers directly 。
半导体集成温度传感器
1.引脚说明
DS18B20的引脚如图4-26所示。 GND:接地端。 DQ:数据输入/输出引脚。单线操作时应使漏极开路。 VCC:可选的电源正极引脚。寄生电源供电方式时接地。
图4-24 AD590
2.数字量半导体集成温度传感器
将温度传感器和A/D转换电路集成在一个芯片上构成的。 将温度信号直接转换为并行或串行数字信号供中央处理器处理, 抗干扰性比模拟量半导体集成温度传感器更强。 广泛应用于工业控制、电子测温计、医疗仪器等各种温度控制与 检测系统中。 典型产品有DS18B20、MAX6575和MAX6635等。
DS18B20工作过程一般遵循:初始化→ROM操作命令→存储器操作命令→处理数据。
图4-27 DS18B20的组成
3.供电方式
(1)寄生电源供电。 特点:① 进行远距离测温时,无须本地电源;② 可以在没
有常规电源的条件下读取ROM;③ 电路更加简洁,仅用一个I/O 口实现测温;④ 只适用于单一温度传感器测温情况。
图4-28 电子温度计系统
传感器原理与应用
3.开关量半导体集成温度传感器
开关量半导体集成温度传感器主要包括温控开关和可编程温度控制器两种。 典型产品有KSD9700、KSD301、MAX6501/02/03/04及其他智能温控开关。
1.2 典型集成温度传感器——数字温度计DS18B20
DS18B20的测量范围为 ~125℃,增量值为0.5℃,可将温度信号直接转换 为9~12位的数字量输出。
图4-25 DS18B20实物 图4-26 DS18由64位ROM、单线端口、温度传感器、存储器和控制逻辑、暂存器、 电源探测、8位CRC产生器、非易失性温度报警触发器TH(上限触发)和TL(下限触发) 等组成。
分布式温度传感器外文翻译
外文翻译(原文)Distributed Temperature SensorIn the human living environment, temperature playing an extremely important role。
No matter where you live, engaged in any work, ever-present dealt with temperature under. Since the 18th century, industry since the industrial revolution to whether can master send exhibition has the absolute temperature touch. In metallurgy, steel, petrochemical, cement, glass, medicine industry and so on, can say almost eighty percent of industrial departments have to consider the factors with temperature. Temperature for industrial so important, thus promoting the development of the temperature sensor.Major general through three sensor development phase: analog integrated temperature sensor. The sensor is taken with silicon semiconductor integrated workmanship, therefore also called silicon sensor or monolithic integrated temperature sensor. Such sensing instruments have single function (only measuring temperature), temperature measurement error is smaller, price low, fast response, the transmission distance, small volume, micro-consumption electronic etc, suitable for long distance measurement temperature, temperature control, do not need to undertake nonlinear calibration, peripheral circuit is simple. It is currently the most common application at home and abroad, an integrated sensor。
DS18B20数字式温度传感器中英文资料外文翻译文献
中英文资料外文翻译文献The introduction to The DS18B201. DESCRIPTIONThe DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line for communication with a central microprocessor. It has an operating temperature range of -55°C to +125°C and is accurate to ±0.5°C over the range of -10°C to +85°C. In addition, the DS18B20 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply.Each DS18B20 has a unique 64-bit serial code, which allows multiple DS18B20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18B20s distributed over a large area. Applications that can benefit from this feature include HV AC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.2.FEATURESUnique 1-Wire® Interface Requires Only One Port Pin for Communication1●Each Device has a Unique 64-Bit Serial Code Stored in an On-Board ROM●Multi-drop Capability Simplifies Distributed Temperature-Sensing Applications ●Requires No External Components●Can Be Powered from Data Line; Power Supply Range is 3.0V to 5.5V●Measures Temperatures from -55°C to +125°C (-67°F to +257°F)●±0.5°C Accuracy from -10°C to +85°C●Thermometer Resolution is User Selectable from 9 to 12 Bits●Converts Temperature to 12-Bit Digital Word in 750ms (Max)●User-Definable Nonvolatile (NV) Alarm Settings●Alarm Search Command Identifies and Addresses Devices Whose Temperature isOutside Programmed Limits●Software Compatible with the DS1822●Applications Include Thermostatic Controls, Industrial Systems, ConsumerProducts, Thermometers, or Any Thermally Sensitive System3.OVERVIEWFigure 1 shows a block diagram of the DS18B20, and pin descriptions are given in the Pin Description table. The 64-bit ROM stores the device’s unique serial code. The scratchpad memory contains the 2-byte temperature register that stores the digital output from the temperature sensor. In addition, the scratchpad provides access to the 1-byte upper and lower alarm trigger registers (TH and TL) and the 1-byte configuration register. The configuration register allows the user to set the resolution of the temperature to-digital conversion to 9, 10, 11, or 12 bits. The TH, TL, and configuration registers are nonvolatile (EEPROM), so they will retain data when the device is powered down.The DS18B20 uses Maxim’s exclusive 1-Wire bus protocol that implements bus communication using one control signal. The control line requires a weak pull up resistor since all devices are linked to the bus via a 3-state or open-drain port (the DQ2pin in the case of the DS18B20). In this bus system, the microprocessor (the master device) identifies and addresses devices on the bus using each device’s unique 64-bit code. Because each device has a unique code, the number of devices that can be addressed on one DS18B20 bus is virtually unlimited. The 1-Wire bus protocol, including detailed explanations of the commands and “time slots,” is covered in the 1-Wire Bus System section.Another feature of the DS18B20 is the ability to operate without an external power supply. Power is instead supplied through the 1-Wire pull up resistor via the DQ pin when the bus is high. The high bus signal also charges an internal capacitor (CPP), which then supplies power to the device when the bus is low. This method of deriving power from the 1-Wire bus is referred to as “parasite power.” As an alternative, the DS18B20 may also be powered by an external supply on VDD.Figure 1.DS18B20 Block Diagram4.OPERATION—MEASURING TEMPERATURThe core functionality of the DS18B20 is its direct-to-digital temperature sensor. The resolution of the temperature sensor is user-configurable to 9, 10, 11, or 12 bits, corresponding to increments of 0.5°C, 0.25°C, 0.125°C, and 0.0625°C, respectively. The default resolution at power-up is 12-bit. The DS18B20 powers up in a low-power idle state. To initiate a temperature measurement and A-to-D conversion, the master must issue a Convert T [44h] command. Following the conversion, the resulting3thermal data is stored in the 2-byte temperature register in the scratchpad memory and the DS18B20 returns to its idle state. If the DS18B20 is powered by an external supply, the master can issue “read time slots” (see the 1-Wire Bus System section) after the Convert T command and the DS18B20 will respond by transmitting 0 while the temperature conversion is in progress and 1 when the conversion is done. If the DS18B20 is powered with parasite power, this notification technique cannot be used since the bus must be pulled high by a strong pull up during the entire temperature conversion.The DS18B20 output temperature data is calibrated in degrees Celsius; for Fahrenheit applications, a lookup table or conversion routine must be used. The temperature data is stored as a 16-bit sign-extended two’s complement number in the temperature register (see Figure 2). The sign bits (S) indicate if the temperature is positive or negative: for positive numbers S = 0 and for negative numbers S = 1. If the DS18B20 is configured for 12-bit resolution, all bits in the temperature register will contain valid data. For 11-bit resolution, bit 0 is undefined. For 10-bit resolution, bits 1 and 0 are undefined, and for 9-bit resolution bits 2, 1, and 0 are undefined. Table 1 gives examples of digital output data and the corresponding temperature reading for 12-bit resolution conversions.4Table 1.Temperature/Data Relationship5.64-BIT LASERED ROM CODEEach DS18B20 contains a unique 64–bit code (see Figure 3) stored in ROM. The least significant 8 bits of the ROM code contain the DS18B20’s 1-Wire family code: 28h. The next 48 bits contain a unique serial number. The most significant 8 bits contain a cyclic redundancy check (CRC) byte that is calculated from the first 56 bits of the ROM code. The 64-bit ROM code and associated ROM function control logic allow the DS18B20 to operate as a 1-Wire device using the protocol detailed in the 1-Wire Bus System section.Figure 3.64-Bit Lasered ROM Code6.MEMORYThe DS18B20’s memory is organized as shown in Figure 4. The memory consists of an SRAM scratchpad with nonvolatile EEPROM storage for the high and low alarm trigger registers (TH and TL) and configuration register. Note that if the DS18B20 alarm function is not used, the TH and TL registers can serve as general-purpose memory.Byte 0 and byte 1 of the scratchpad contain the LSB and the MSB of the temperature register, respectively. These bytes are read-only. Bytes 2 and 3 provide access to TH and TL registers. Byte 4 contains the configuration register data. Bytes 5, 6, and 7 are reserved for internal use by the device and cannot be overwritten. Byte 8 of the scratchpad is read-only and contains the CRC code for bytes 0 through 7 of the scratchpad. The DS18B20 generates this CRC using the method described in the CRC Generation section.Data is written to bytes 2, 3, and 4 of the scratchpad using the Write Scratchpad [4Eh] command; the data must be transmitted to the DS18B20 starting with the least56significant bit of byte 2. To verify data integrity, the scratchpad can be read (using the Read Scratchpad [BEh] command) after the data is written. When reading the scratchpad, data is transferred over the 1-Wire bus starting with the least significant bit of byte 0. To transfer the TH, TL and configuration data from the scratchpad to EEPROM, the master must issue the Copy Scratchpad [48h] command.7.CONFIGURATION REGISTERByte 4 of the scratchpad memory contains the configuration register, which is organized as illustrated in Figure 5. The user can set the conversion resolution of the DS18B20 using the R0 and R1 bits in this register as shown in Table 2. The power-up default of these bits is R0 = 1 and R1 = 1 (12-bit resolution). Note that there is a direct tradeoff between resolution and conversion time. Bit 7 and bits 0 to 4 in the configuration register are reserved for internal useby the device and cannot be overwritten.8.1-WIRE BUS SYSTEMThe 1-Wire bus system uses a single bus master to control one or more slave devices. The DS18B20 is always a slave. When there is only one slave on the bus, the system is referred to as a “single-drop” system; the system is “multi-drop” if there are multiple slaves on the bus. All data and commands are transmitted least significant bit first over the 1-Wire bus. The following discussion of the 1-Wire bus system is broken down into three topics: hardware configuration, transaction sequence, and1-Wire signaling (signal types and timing).9.TRANSACTION SEQUENCEThe transaction sequence for accessing the DS18B20 is as follows:Step 1. InitializationStep 2. ROM Command (followed by any required data exchange)Step 3. DS18B20 Function Command (followed by any required data exchange)It is very important to follow this sequence every time the DS18B20 is accessed, as the DS18B20 will not respond if any steps in the sequence are missing or out of order. Exceptions to this rule are the Search ROM [F0h] and Alarm Search [ECh] commands. After issuing either of these ROM commands, the master must return to Step 1 in the sequence.(1)INITIALIZATIONAll transactions on the 1-Wire bus begin with an initialization sequence. The initialization sequence consists of a reset pulse transmitted by the bus master followed7by presence pulse(s) transmitted by the slave(s). The presence pulse lets the bus master know that slave devices (such as the DS18B20) are on the bus and are ready to operate.(2)ROM COMMANDSAfter the bus master has detected a presence pulse, it can issue a ROM command. These commands operate on the unique 64-bit ROM codes of each slave device and allow the master to single out a specific device if many are present on the 1-Wire bus. These commands also allow the master to determine how many and what types of devices are present on the bus or if any device has experienced an alarm condition. There are five ROM commands, and each command is 8 bits long. The master device must issue an appropriate ROM command before issuing a DS18B20 function command.1.SEARCH ROM [F0h]When a system is initially powered up, the master must identify the ROM codes of all slave devices on the bus, which allows the master to determine the number of slaves and their device types. The master learns the ROM codes through a process of elimination that requires the master to perform a Search ROM cycle (i.e., Search ROM command followed by data exchange) as many times as necessary to identify all of the slave devices. If there is only one slave on the bus, the simpler Read ROM command can be used in place of the Search ROM process.2.READ ROM [33h]This command can only be used when there is one slave on the bus. It allows the bus master to read the slave’s 64-bit ROM code without using the Search ROM procedure. If this command is used when there is more than one slave present on the bus, a data collision will occur when all the slaves attempt to respond at the same time.3.MATCH ROM [55h]The match ROM command followed by a 64-bit ROM code sequence allows8the bus master to address a specific slave device on a multi-drop or single-drop bus. Only the slave that exactly matches the 64-bit ROM code sequence will respond to the function command issued by the master; all other slaves on the bus will wait for a reset pulse.4.SKIP ROM [CCh]The master can use this command to address all devices on the bus simultaneously without sending out any ROM code information. For example, the master can make all DS18B20s on the bus perform simultaneous temperature conversions by issuing a Skip ROM command followed by a Convert T [44h] command. Note that the Read Scratchpad [BEh] command can follow the Skip ROM command only if there is a single slave device on the bus. In this case, time is saved by allowing the master to read from the slave without sending the device’s 64-bit ROM code. A Skip ROM command followed by a Read Scratchpad command will cause a data collision on the bus if there is more than one slave since multiple devices will attempt to transmit data simultaneously.5.ALARM SEARCH [ECh]The operation of this command is identical to the operation of the Search ROM command except that only slaves with a set alarm flag will respond. This command allows the master device to determine if any DS18B20s experienced an alarm condition during the most recent temperature conversion. After every Alarm Search cycle (i.e., Alarm Search command followed by data exchange), the bus master must return to Step 1 (Initialization) in the transaction sequence.(3)DS18B20 FUNCTION COMMANDSAfter the bus master has used a ROM command to address the DS18B20 with which it wishes to communicate, the master can issue one of the DS18B20 function commands. These commands allow the master to write to and read from the D S18B20’s scratchpad memory, initiate temperature conversions and determine the power supply mode.91.CONVERT T [44h]This command initiates a single temperature conversion. Following the conversion, the resulting thermal data is stored in the 2-byte temperature register in the scratchpad memory and the DS18B20 returns to its low-power idle state. If the device is being used in parasite power mode, within 10µs (max) after this command is issued the master must enable a strong pull up on the 1-Wire bus. If the DS18B20 is powered by an external supply, the master can issue read time slots after the Convert T command and the DS18B20 will respond by transmitting a 0 while the temperature conversion is in progress and a 1 when the conversion is done. In parasite power mode this notification technique cannot be used since the bus is pulled high by the strong pull up during the conversion.2.READ SCRATCHPAD [BEh]This command allows the master to read the contents of the scratchpad. The data transfer starts with the least significant bit of byte 0 and continues through the scratchpad until the 9th byte (byte 8 – CRC) is read. The master may issue a reset to terminate reading at any time if only part of the scratchpad data is needed.3.WRITE SCRATCHPAD [4Eh]This comm and allows the master to write 3 bytes of data to the DS18B20’s scratchpad. The first data byte is written into the TH register (byte 2 of the scratchpad), the second byte is written into the TL register (byte 3), and the third byte is written into the configuration register (byte 4). Data must be transmitted least significant bit first. All three bytes MUST be written before the master issues a reset, or the data may be corrupted.4.COPY SCRATCHPAD [48h]This command copies the contents of the scratchpad TH, TL and configuration registers (bytes 2, 3 and 4) to EEPROM. If the device is being used in parasite power mode, within 10µs (max) after this command is issued the master must enable a10strong pull-up on the 1-Wire bus.5.RECALL E2 [B8h]This command recalls the alarm trigger values (TH and TL) and configuration data from EEPROM and places the data in bytes 2, 3, and 4, respectively, in the scratchpad memory. The master device can issue read time slots following the Recall E2command and the DS18B20 will indicate the status of the recall by transmitting 0 while the recall is in progress and 1 when the recall is done. The recall operation happens automatically at power-up, so valid data is available in the scratchpad as soon as power is applied to the device.6.READ POWER SUPPL Y [B4h]The master device issues this command followed by a read time slot to determine if any DS18B20s on the bus are using parasite power. During the read time slot, parasite powered DS18B20s will pull the bus low, and externally powered DS18B20s will let the bus remain high.10.WIRE SIGNALINGThe DS18B20 uses a strict 1-Wire communication protocol to ensure data integrity. Several signal types are defined by this protocol: reset pulse, presence pulse, write 0, write 1, read 0, and read 1. The bus master initiates all these signals, with the exception of the presence pulse.(1)INITIALIZATION PROCEDURE—RESET AND PRESENCE PULSES All communication with the DS18B20 begins with an initialization sequence that consists of a reset pulse from the master followed by a presence pulse from the DS18B20. This is illustrated in Figure 6. When the DS18B20 sends the presence pulse in response to the reset, it is indicating to the master that it is on the bus and ready to operate.During the initialization sequence the bus master transmits (TX) the reset pulse by pulling the 1-Wire bus low for a minimum of 480µs. The bus master then releases11the bus and goes into receive mode (RX). When the bus is released, the 5kΩ pull-up resistor pulls the 1-Wire bus high. When the DS18B20 detects this rising edge, it waits 15µs to 60µs and then transmits a presence pulse by pulling the 1-Wire bus low for 60µs to 240µs.TimingBus master pulling lowDS18B20 pulling lowResistor pullupFigure 6.Initialization Timing(2)READ/WRITE TIME SLOTSThe bus master writes data to the DS18B20 during write time slots and reads data from the DS18B20 during read time slots. One bit of data is transmitted over the 1-Wire bus per time slot.1.WRITE TIME SLOTSThere are two types of write time slots: “Write 1” time slots and “Write 0” time slots. The bus master uses a Write 1 time slot to write a logic 1 to the DS18B20 and a Write 0 time slot to write a logic 0 to the DS18B20. All write time slots must be a minimum of 60µs in duration with a minimum of a 1µs recovery time between individual write slots. Both types of write time slots are initiated by the master pulling the 1-Wire bus low (see Figure 7).To generate a Write 1 time slot, after pulling the 1-Wire bus low, the bus master must release the 1-Wirebus within 15µs. When the bus is released, the 5kΩ pull-up resistor will pull the bus high. To generate a Write 0 time slot, after pulling the 1-Wire1213bus low, the bus master must continue to hold the bus low for the duration of the time slot (at least 60µs).The DS18B20 samples the 1-Wire bus during a window that lasts from 15µs to 60µs after the master initiates the write time slot. If the bus is high during the sampling window, a 1 is written to the DS18B20. If the line is low, a 0 is written to the DS18B20.DS18B20Write Time SlotSTART OF SLOTVccBus master pulling low Resistor pullupFigure 7.DS18B20 Write Time Slot2.READ TIME SLOTSThe DS18B20 can only transmit data to the master when the master issues read time slots. Therefore, the master must generate read time slots immediately after issuing a Read Scratchpad [BEh] or Read Power Supply [B4h] command, so that the DS18B20 can provide the requested data. In addition, the master can generate read time slots after issuing Convert T [44h] or Recall E 2 [B8h] commands to find out the status of the operation.All read time slots must be a minimum of 60µs in duration with a minimum of a 1µs recovery time between slots. A read time slot is initiated by the master device pulling the 1-Wire bus low for a minimum of 1µs and then releasing the bus (see Figure 8). After the master initiates the read time slot, the DS18B20 will begin transmitting a 1 or 0 on bus. The DS18B20 transmits a 1 by leaving the bus high andtransmits a 0 by pulling the bus low. When transmitting a 0, the DS18B20 will release the bus by the end of the time slot, and the bus will be pulled back to its high idle state by the pull up resister. Output data from the DS18B20 is valid for 15µs after the falling edge that initiated the read time slot. Therefore, the master must release the bus and then sample the bus state within 15µs from the start of the slot.VccBus master pulling lowResistor pullupDS18B20 pulling lowFigure 8.DS18B20 Read Time Slot1415DS18B20介绍1.说明DS18B20数字式温度传感器提供9位到12位的摄氏温度测量,并且有用户可编程的、非易失性温度上下限告警出发点。
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附录CThe integrated temperature sensor is a kind of semiconductor integrated circuit in fact, it is who utilizes the transistor b-e Form saturation value lowered to press V BE With thermodynamics temperature T With passing the emitter electric current I Relation.It is good that the integrated temperature sensor is linear, such advantages as the precision ismoderate, the sensitivity is high,small, easy to use, used widely. The output form9 of the integrated temperature sensor is divided into two kinds voltage exporting and electric current outputs. The sensitivity of the voltage outputting type is generally 10mV/K, Temperature0 Degrees Centigrade are exported hour 0 ,Temperature25 Degrees Centigrade are exported hour 2.982V . The sensitivity of the outputting type of the electric current is generally 1 μ A/K .AD590 It is the single integrated temperature sensing electric current source of both ends where U.S.A. simulation device Company produces. Its main characteristic is as follows:(1) flow through device electric current ( μ A )Mean the reading of thermodynamics temperature (turns on gently ) of living in environment of the device.(2) AD590 Examine warm range -55 Degrees Centigrade- +150 Degrees Centigrade.(3) AD590 Power voltage range 4V -30V . The voltage of the power can be here 4V~6V The range changes, electric current Change 1 μA,In other words temperature changes 1K . AD590 Can bear 44V To voltage sum 20V Reverse voltage, therefore the transposition of the device will not be damaged either.(4) the resistance of output is 710MΩ.(5)the precision is high. AD590 Own in common I J K L M Five shelves, among them M The shelf is the highest in precision, here -55 Degrees Centigrade- +150 In one degrees Centigrade of ranges, the non-linear error is ±0.3 Degrees Centigrade.1、the application circuit basicallyPursue 1 ( a)AD590 Encapsulation form, pursue 1 ( b )AD590 Used for measuring using the circuit basically of thermodynamics temperature. Because flow throughAD590 Electric current in direct proportion to thermodynamics temperature, look on as resistance R 1 With the electric potential device R 2 Resistance sum 1k ΩHour, output the voltage VO The change which is up to temperature is 1mV/K . But because AD590 Gain by deviation of having, resistance too it have error of, so should adjust to circuit. The method to adjust is: One AD590 Put in the frozen water mixture, the electric potential adjusting device R 2 ,Make VO =273.2mV . Or under the room temperature (25 Degrees Centigrade )Pursue 1 ( a)AD590 Encapsulation form, pursue 1 ( b )AD590 Used for measuring using the circuit basically of thermodynamics temperature. Because flow through AD590 Electric current in direct proportion to thermodynamics temperature, look on as resistance R 1 With the electric potential device R 2 Resistance sum 1k ΩHour, output the voltage VO The change which is up to temperature is 1mV/K . But because AD590 Gain by deviation of having, resistance too it have error of, so should adjust to circuit. The method to adjust is: One AD590 Put in the frozen water mixture, the electric potential adjusting device R 2 ,Make VO =273.2mV . Or under the room temperature (25 Degrees Centigrade) too it have error of, so should adjust to circuit. The method to adjust is: One AD590 Put in the frozen water mixture, electric potential adjusting device R 2 ,Make VO =273.2mV . Or under the room temperature (25 Degrees Centigrade )Adjust the electric potential device under the condition ,Make VO =273.2+25 =298.2 ( mV ). But it is here to change and only guarantee like this 0 Degrees Centigrade or 25 There is high accuracy degrees Centigrade of nearby.2、Centigrade temperature survey circuitSuch as pursuing2 Show, the electric potential device R 2 Used for adjusting the zero point, R 4 Used for changing and transporting putting LF355 Gain. Adjust the method as follows: Here 0 Degrees Centigrade are adjusted hour R 2 ,Enable exporting VO =0 ,Then here 100 Degrees Centigrade are adjusted hour R 4 Make VO =100mV . Such repetition change numerous, until 0 A hour, VO =0mV ,100 A hour VO =100mV . Carry on check-up under the room temperature finally. For example, if the room temperature is 25 Degrees Centigrade, so VO Answer 25mV . The frozen water mixture is 0 One degrees Centigrade of environments, the boiling water is 100 One degrees Centigrade of environments.Enable pursuing2 The output of China is 200mV/ Degrees Centigrade, canfeedback through increasing (picture feedback resistance of for resistance from R 3 With the electric potential device R 4 Contact but become) realize. In addition, while measuring the Fahrenheit temperature , because Fahrenheit temperature is equal to thermodynamics temperature to deduct 255.4 Multiplied by again 9/5 ,So demand to export 1mV/ ℉, adjusts the resistance of feed backing about 180k Ω,Make temperature 0 A hour, VO =17.8mV ; Temperature is 100 A hour, VO =197.8mV .AD581 It is a high-accuracy integrated voltage stabilizer , most greatly input the voltage 40V ,Output 10V .3、 the difference in temperature measures the circuit and application(1) Circuit and principle analysisPursue 3 Utilize two AD590 Measure two circuit with bad temperature. Feed backing the resistance 100k ΩSituation under, set up 1 # Sum 2 # AD590 The temperature of the place is respectively 1t (degrees Centigrade) sum 2t (whether degrees Centigrade),it output voltage as ()12100/t t mv C - . Electric potential device in the picture R 2 Used for returning to zero.Electric potential device R 4 Used for changing and transporting putting LF355 Gain.(2) Use and give an exampleTake warm in some energy-efficient crude drugs warehouse , humidity control system as an example, if require the temperature of the storehouse is lower than T Degrees Centigrade, relative humidity is lower than A 1 B 1 %RH . Two kinds of control modes adopted are as follows:Control mode one: The relative humidity is higher than in the storehouse A 1 B 1 %RH And temperature is lower than outside the storehouse T A hour, ventilate inside and outside the storehouse. This way is to utilize bad exchange which carries on the air of the internal and external humidity of the storehouse, in order to reach the demand dehumidifying in the storehouse, its advantage is high-efficient , energy-conservation , saving the fund. But this way receives strict control. First of all, the relative humidity outside the storehouse will lower than the storehouse, the difference between them should be greater than A 2 B 2 %RH ,Could guarantee to carry on the dehumidification in the storehouse in time effectively in this way. Secondly, the temperature outside the storehouse should be smaller than badly in the storehouse.Degrees Centigrade, this because if temperature ventilate at higher than temperature in the store housing far outside storehouse, will lead to the fact themedicines , apparatus surface form the phenomenon revealed when meeting the cold air after the hot air enters the reservoir area, and then influence the quality of the medicines and apparatus. On the contrary, if temperature ventilate at higher than temperature outside the store housing far in storehouse, the cold air will be formed and revealed on the medicines apparatus surface too after entering storehouse. In addition, temperature can't be close outside the storehouse T Degrees Centigrade. This is because, if temperature is close outside the storehouse T Is it ventilate to go on when the degrees Centigrade , make airtight storehouse warm to rise most likely , thus exceed the upper limit of temperature T Degrees Centigrade.Control the mode two: As temperature is higher than T Degrees Centigrade or the humidity are higher than A 1 B 1 %RH At unsatisfied with first stationing , open frozen air conditioner aircrew carry on storehouse lower the temperature to dehumidify.Because storehouse internal and external difference in temperature too big the medicines , apparatus surface marry the phenomenon revealed when ventilating for prevent from, must rigorously enforce the precision of the value of difference in temperature of the control system . Traditional examining the method of difference in temperature is to deal with two temperature separately (nurse one's health in the circuit, A/D , deal with operation) after ask by difference, the low in precision in difference in temperature in income in method . The measurement of internal and external difference in temperature of the storehouse can be adopted and pursued 3 Shown circuit, utilize value of difference in temperature to compare with the establishing value directly , can guarantee higher precision , and the software design of the reduced system, has improved systematic dependability .4、N Measurement of some minimum temperature valueWill examine a bit more warmly several that have differently AD590 Contact , can measure all measure temperature minimum value that point have.This method can apply to measure some occasions of minimum temperature more .5、N Measurement of the average of some temperatureOne N One AD590 Is it stand up to connect in parallel , fetch after suing for peace electric current average , can is it produce average temperature to ask.This method is suitable for needing some average temperature more but notneeding the occasion of concrete temperature of each point .AD590 Measure thermodynamics temperature , centigrade temperature , two temperature bad , many some minimum temperature , many some average concrete circuit of temperature, apply to different temperature control occasions extensively. Because AD590 Precision high, price low taking auxiliary power , linear and good , daily on examine gentle cold end of electric thermocouple compensate.集成温度传感器实质上是一种半导体集成电路,它是利用晶体管的b-e结压降的不饱和值V BE与热力学温度T和通过发射极电流I的下述关系实现对温度的检测。