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可编程恒功率传感器
早期的可编程控制器虽然采用了计算机技术的优点和设计思想，并注重了面向用户、用于控制和适合工业现场的特点，但限于当时的技术发展水平，其功能很有限，器件多、线路复杂且体积大，名称也不统一。
随着网络技术的发展，现代可编程控制器对网络功能的要求更强，一般都有现场总线功能、互连网接入功能等，EASY嵌入式PLC采用CAN bus现场总线技术并支持专用的嵌入式Web服务器。
2003年，中国PLC市场规模达26.8亿人民币，小型PLC占64%，由于中国制造业的高速发展，市场未来可望保持年15%的增长率。
在传统的单机设备控制增长的前提下，PLC正在压缩单片机应用市场，挤占DCS份额，与IPC全面对抗。
中国的PLC市场，仅5%为本土化产品，其他均为国外制造。在压缩单片机市场和IPC市场的竞争中，具有现场总线和互连网接入功能的PLC（尤其是小型PLC）体现出强大竞争力，EASY嵌入式PLC正是在这种市场推动下产生的。
改革开放30年来，我国传感器技术及其产业取得了长足进步。在“九五”国家重点科技攻关项目中，传感器技术研究取得了51个品种86个规格新产品的成绩，初步建立了敏感元件与传感器产业；2007年传感器业总产量达到20.93亿只，品种规格已有近6000种，并已在国民经济各部门和国防建设中得到一定应用。
传感器是一种物理装置或生物器官，能够探测、感受外界的信号、物理条件（如光、热、湿度）或化学组成（如烟雾），并将探知的信息传递给其他装置或器官。随着我国传感器市场的迅猛发展，与之相关的核心生产技术应用与研发必将成为业内企业关注的焦点。了解国内外传感器生产核心技术的研发动向、工艺设备、技术应用及趋势对于企业提升产品技术规格，提高市场竞争力十分关键。
国家标准GB7665-87对传感器下的定义是：“能感受规定的被测量并按照一定的规律转换成可用信号的器件或装置，通常由敏感元件和转换元件组成”。传感器是一种监测装置，能感受到被测量的信息，并能将检测感受到的信息，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。它是实现自动检测和自动控制的首要环节。
传感器可以用不同的观点就行分类：它们的转换原理（传感器工作的基本物理或化学效应）：它们的用途：：他们的输出信号类型以及制作它们的材料和工艺等。
根据传感器的工作原理，可以分为物理传感器和化学传感器两大类：
传感器工作原理的分类物理传感器应用的是物理效应，诸如压电效应，磁致伸缩现象，离化、极化、热点、光电、磁电等效应。被测信号量的微小变化都将转换成电信号。
化学传感器包括那些以化学吸附、电化学反应等现象为因果关系的传感器，被测信号量的微小变化也将转换成电信号。
有些传感器既不能划分到物理类，也不能划分为化学类。大多数传感器是以物理原理为基础运作的。化学传感器技术问题较多，例如可靠性问题，规模生产的可能性，价格问题等，解决了这类难题，化学传感器的应用将会有巨大增长。
传感器工作原理的分类物理传感器应用的是物理效应，诸如压电效应，磁致伸缩现象，离化、极化、热电、光电、磁电等效应。被测信号量的微小变化都将转换成电信号。化学传感器包括那些以化学吸附、电化学反应等现象为因果关系的传感器，被测信号量的微小变化也将转换成电信号。向传感器提供±15V电源，激磁电路中的晶体振荡器产生400Hz的方波，经过TDA2030功率放大器即产生交流激磁功率电源，通过能源环形变压器T1从静止的初级线圈得到的交流电源通过轴上的整流滤波电路得到±5V的直流电源，该电源 做运算放大器AD822的工作电源；由基准电源AD589与双运放AD822组成的高精度稳压电源产生±4.5V的精密直流电源，该电源既作为电桥电源，又作为放大器及V/F转换器的工作电源。当弹性轴受扭时，应变桥检测得到的mV级的应变信号通过仪表放大器AD620放大成1.5V±1V的强信号，再通过V/F转换器LM131变换成频率信号，通过信号环形变压器T2从旋转的初级线圈传递至静止次级线圈，再经过外壳上的信号处理电路滤波、整形即可得到与弹性轴承受的扭矩成正比的频率信号，该信号为TTL电平，既可提供给专用二次仪表或频率计显示也可直接送计算机处理。由于该旋转变压器动—静环之间只有零点几毫米的间隙，加之传感器轴上部分都密封在金属外壳之内，形成有效的屏蔽，因此具有很强的抗干扰能力。有些传感器既不能划分到物理类，也不能划分为化学类。大多数传感器是以物理原理为基础运作的。化学传感器技术问题较多，例如可靠性问题，规模生产可能性，价格问题等，解决了这类难题，化学传感器的应用将会有巨大增长。
传感器的应用常见的有自动门，利用人体的红外微波来开关门；烟雾报警器，利用烟敏电阻来测量延误浓度，从而达到报警目的；手机，数码相机的照相机，利用光学传感器来捕获图像；电子称，利用力学传感器（导体应变片技术）来测量物体对应变片的压力，从而达到测量重量目的；水位报警；温度报警；湿度报警；光学报警等。
智能传感器已广泛应用于航天、航空、国防、科技和工农业生产等各个领域中。例如，它在机器人领域中有着广阔应用前景，智能传感器使机器人具有类人的五官和大脑功能，可感知各种现象，完成各种动作。在工业生产中，利用传统的传感器无法对某些产品质量指标（例如，黏度、硬度、表面光洁度、、成分、颜色及味道等）进行快速直接测量并在线控制。而利用智能传感器可直接测量与产品质量指标有函数关系的生产过程中的某些量（如温度、压力、流量等）。Cygnus公司生产力一种“葡萄糖手表”，其外观像普通手表一样，戴上它就能实现无疼、无血、连续的血糖测试。“葡萄糖手表”上有一块涂着试剂的垫子，当垫子与皮肤接触时，葡萄糖分子就被吸附附到垫子上，并与试剂发生电化学反应，产生电流。传感器测量该电流，经处理器计算出与该电流对应的血糖浓度，并以数字量显示。
当前中国是长的现状是市场急剧增长、品种快速增加；高端依赖进口，低端渐增出口；厂商众多如林，难觅顶尖品牌；一般技术趋稳，价格逐年下降；核心技术难觅，研究生产相离，国内传感器主要市场仍被世界驰名品牌所占领。
功能
常将传感器的功能与人类5大感觉器官相比拟： 光敏传感器——视觉 声敏传感器——听觉 气敏传感器——嗅觉 化学传感器——味觉 压敏、温敏、流体传感器——触觉 敏感元件的分类： ①物理类，基于力、热、光、电、磁和声等物理效应。 ②化学类，基于化学反应的原理。 ③生物类，基于酶、抗体、和激素等分子识别功能。 通常据其基本感知功能可分为热敏元件、光敏元件、气敏元件、力敏元件、磁敏元件、湿敏元件、声敏元件、放射线敏感元件、色敏元件和味敏元件等十大类（还有人曾将敏感元件分46类）。
编辑本段特点
新型传感器的特点包括：微型化、数字化、智能化、多功能化、系统化、网络化，它不仅促进了传统产业的改造和更新换代，而且还可能建立新型工业，从而成为21世纪新的经济增长点。微型化是建立在微电子机械系统(MEMS)技术基础上的，目前已成功应用在硅器件上做成硅压力传感器。
可以用不同的观点对传感器进行分类：
它们的转换原理(传感器工作的基本物理或化学效应)；它们的用途；它们的输出信号类型以及制作它们的材料和工艺等。
根据传感器工作原理，可分为物理传感器和化学传感器二大类：
传感器工作原理的分类物理传感器应用的是物理效应，诸如压电效应，磁致伸缩现象，离化、极化、热电、光电、磁电等效应。被测信号量的微小变化都将转换成电信号。
化学传感器包括那些以化学吸附、电化学反应等现象为因果关系的传感器，被测信号量的微小变化也将转换成电信号。
有些传感器既不能划分到物理类，也不能划分为化学类。大多数传感器是以物理原理为基础运作的。化学传感器技术问题较多，例如可靠性问题，规模生产的可能性，价格问题等，解决了这类难题，化学传感器的应用将会有巨大增长。
常见传感器的应用领域和工作原理列于下表。
1.传感器按照其用途分类
压力敏和力敏传感器位置传感器
液面传感器能耗传感器
速度传感器加速度传感器
射线辐射传感器 热敏传感器
24GHz雷达传感器
2.传感器按照其原理分类
振动传感器 湿敏传感器
磁敏传感器 气敏传感器
真空度传感器 生物传感器等。
3.传感器按照其输出信号为标准分类
模拟传感器——将被测量的非电学量转换成模拟电信号。
数字传感器——将被测量的非电学量转换成数字输
出信号(包括直接和间接转换)。
膺数字传感器——将被测量的信号量转换成频率信号或短周期信号的输出(包括直接或间接转换)。
开关传感器——当一个被测量的信号达到某个特定的阈值时，传感器相应地输出一个设定的低电平或高电平信号。
4.传感器按照其材料为标准分类
在外界因素的作用下，所有材料都会作出相应的、具有特征性的反应。它们中的那些对外界作用最敏感的材料，即那些具有功能特性的材料，被用来制作传感器的敏感元件。从所应用的材料观点出发可将传感器分成下列几类：
(1)按照其所用材料的类别分
金属聚合物陶瓷混合物
(2)按材料的物理性质分：
导体绝缘体 半导体磁性材料
(3)按材料的晶体结构分：
单晶多晶非晶材料
与采用新材料紧密相关的传感器开发工作，可以归纳为下述三个方向：
(1)在已知的材料中探索新的现象、效应和反应，然后使它们能在传感器技术中得到实际使用。
(2)探索新的材料，应用那些已知的现象、效应和反应来改进传感器技术。
(3)在研究新型材料的基础上探索新现象、新效应和反应，并在传感器技术中加以具体实施。
现代传感器制造业的进展取决于用于传感器技术的新材料和敏感元件的开发强度。传感器开发的基本趋势是和半导体以及介质材料的应用密切关联的。表1.2中给出了一些可用于传感器技术的、能够转换能量形式的材料。
5.传感器按照其制造工艺分类
集成传感器薄膜传感器 厚膜传感器陶瓷传感器
集成传感器是用标准的生产硅基半导体集成电路的工艺技术制造的。通常还将用于初步处理被测信号的部分电路也集成在同一芯片上。
薄膜传感器则是通过沉积在介质衬底(基板)上的，相应敏感材料的薄膜形成的。使用混合工艺时，同样可将部分电路制造在此基板上。
厚膜传感器是利用相应材料的浆料，涂覆在陶瓷基片上制成的，基片通常是Al2O3制成的，然后进行热处理，使厚膜成形。
陶瓷传感器采用标准的陶瓷工艺或其某种变种工艺(溶胶-凝胶等)生产。
完成适当的预备性操作之后，已成形的元件在高温中进行烧结。厚膜和陶瓷传感器这二种工艺之间有许多共同特性，在某些方面，可以认为厚膜工艺是陶瓷工艺的一种变型。
每种工艺技术都有自己的优点和不足。由于研究、开发和生产所需的资本投入较低，以及传感器参数的高稳定性等原因，采用陶瓷和厚膜传感器比较合理。
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6.传感器根据测量目的不同分类
物理型传感器是利用被测量物质的某些物理性质发生明显变化的特性制成的。
化学型传感器是利用能把化学物质的成分、浓度等化学量转化成电学量的敏感元件制成的。
生物型传感器是利用各种生物或生物物质的特性做成的，用以检测与识别生物体内化学成分的传感器。
7.传感器按照其构成的不同分类
基本型传感器：是一种最基本的单个变换装置。
组合型传感器：是由不同单个变换装置组合而构成的传感器。
应用型传感器：是基本型传感器或组合型传感器与其他机构组合而构成的传感器。
8.传感器按照其作用形式的不同分类
按作用形式可分为主动型和被动型传感器。
主动型传感器又有作用型和反作用型，此种传感器对被测对象能发出一定探测信号，能检测探测信号在被测对象中所产生的变化，或者由探测信号在被测对象中产生某种效应而形成信号。检测探测信号变化方式的称为作用型，检测产生响应而形成信号方式的称为反作用型。雷达与无线电频率范围探测器是作用型实例，而光声效应分析装置与激光分析器是反作用型实例。
被动型传感器只是接收被测对象本身产生的信号，如红外辐射温度计、红外摄像装置等
传感器静态特性
传感器的静态特性是指对静态的输入信号，传感器的输出量与输入量之间所具有相互关系。因为这时输入量和输出量都和时间无关，所以它们之间的关系，即传感器的静态特性可用一个不含时间变量的代数方程，或以输入量作横坐标，把与其对应的输出量作纵坐标而画出的特性曲线来描述。表征传感器静态特性的主要参数有：线性度、灵敏度、迟滞、重复性、漂移等。
（1）线性度：指传感器输出量与输入量之间的实际关系曲线偏离拟合直线的程度。定义为在全量程范围内实际特性曲线与拟合直线之间的最大偏差值与满量程输出值之比。
（2）灵敏度：灵敏度是传感器静态特性的一个重要指标。其定义为输出量的增量与引起该增量的相应输入量增量之比。用S表示灵敏度。
（3）迟滞：传感器在输入量由小到大（正行程）及输入量由大到小（反行程）变化期间其输入输出特性曲线不重合的现象成为迟滞。对于同一大小的输入信号，传感器的正反行程输出信号大小不相等，这个差值称为迟滞差值。
（4）重复性：重复性是指传感器在输入量按同一方向作全量程连续多次变化时，所得特性曲线不一致的程度。
（5）漂移：传感器的漂移是指在输入量不变的情况下，传感器输出量随着时间变化，此现象称为漂移。产生漂移的原因有两个方面：一是传感器自身结构参数；二是周围环境（如温度、湿度等）。
传感器动态特性
所谓动态特性，是指传感器在输入变化时，它的输出的特性。在实际工作中，传感器的动态特性常用它对某些标准输入信号的响应来表示。这是因为传感器对标准输入信号的响应容易用实验方法求得，并且它对标准输入信号的响应与它对任意输入信号的响应之间存在一定的关系，往往知道了前者就能推定后者。最常用的标准输入信号有阶跃信号和正弦信号两种，所以传感器的动态特性也常用阶跃响应和频率响应来表示。
传感器的线性度
通常情况下，传感器的实际静态特性输出是条曲线而非直线。在实际工作中，为使仪表具有均匀刻度的读数，常用一条拟合直线近似地代表实际的特性曲线、线性度（非线性误差）就是这个近似程度的一个性能指标。
拟合直线的选取有多种方法。如将零输入和满量程输出点相连的理论直线作为拟合直线；或将与特性曲线上各点偏差的平方和为最小的理论直线作为拟合直线，此拟合直线称为最小二乘法拟合直线。
传感器的分辨率
分辨率是指传感器可感受到的被测量的最小变化的能力。也就是说，如果输入量从某一非零值缓慢地变化。当输入变化值未超过某一数值时，传感器的输出不会发生变化，即传感器对此输入量的变化是分辨不出来的。只有当输入量的变化超过分辨率时，其输出才会发生变化。
通常传感器在满量程范围内各点的分辨率并不相同，因此常用满量程中能使输出量产生阶跃变化的输入量中的最大变化值作为衡量分辨率的指标。上述指标若用满量程的百分比表示，则称为分辨率。分辨率与传感器的稳定性有负相相关性。
sensor technology and its industry
30 years of reform and opening up, China's sensor technology and its industry has made great progress. In the" Nine Five" national key scientific and technological project, the research of sensor technology has51varieties of 86 specifications of new product success, preliminary built sensor industry;2007sensor industry total production reached 2093000000, nearly6000varieties of different specifications, and has various departments in the national economy and national defense construction in certain application.
The sensor is a physical device or biological organs, can detect, the external signal, the physical conditions (such as light, heat, humidity ) or chemical composition ( such as smoke ), and will explore the information to other devices or organ. China's sensor market's rapid development, and the related core production technology application and development will become the focus of attention of the enterprise. Understanding of domestic and foreign production of core technology research and development trend of sensor technology, equipment, technology application and trend for the enterprises to improve product technical specifications, improve market competitiveness is the key.
The national standard GB7665-87 on the sensor under the definition is: " to be provided to the feelings of measurement and according to certain rules can be used to convert the signal of the device or devices, usually by the sensor and conversion components". The sensor is a device for monitoring, can feel the measured information, and can check the sensed information, according to a certain law transform into electric signal or other desired information in the form of output, in order to meet the needs of information transmission, processing, storage, display, record and control requirements. It is to realize the automatic detection and automatic control of the primary link.
The sensor can be used in different point of view on the line classification: their conversion principle ( sensor the basic physical or chemical effect): their use:: their output signal type and the production of their materials and technology.
According to the working principle of the sensor, can be divided into physical sensors and chemical sensor two categories:
Working principle of the sensor of the classification of the physical sensor application is the physical effects, such as the piezoelectric effect, the phenomenon of magnetostrictive, ionization, polarization, heat, photoelectric, magnetoelectric effect. The measured signal of small changes are converted into electrical signals.
Chemical sensors including those by chemical adsorption, electrochemical reaction phenomenon for the causality of sensor, the measured signal is small changes will also be converted to electrical signals.
Some sensors can be divided into physical class, also cannot be divided into chemical class. The majority of sensor is based on physical principles operation. Chemical sensor technology problems, such as reliability, the scale of production possibilities, price problem, to solve this kind of problem, chemical sensor applications will have tremendous growth.
Working principle of the sensor of the classification of the physical sensor application is the physical effects, such as the piezoelectric effect, the phenomenon of magnetostrictive, ionization, polarization, thermoelectric, photoelectric, magnetoelectric effect. The measured signal of small changes are converted into electrical signals. Chemical sensors including those by chemical adsorption, electrochemical reaction phenomenon for the causality of sensor, the measured signal is small changes will also be converted to electrical signals. The sensor provides a + 15V power supply, exciting circuit of the crystal oscillator to generate the400Hz square wave, after TDA2030 power amplifier which produces AC excitation power supply, energy through the annular transformer T1from a primary coil of AC power through the shaft of the rectifying and filtering circuit gets +5V DC power supply, the power amplifier AD822working power supply; power supply by the baseline AD589and dual operational amplifier AD822 consisting of high precision power supply generating +4.5V precision DC power supply, the power supply is used as a bridge power supply, and as an amplifier and V / F converter power supply. When the flexible shaft in torsion, strain bridge was detected by mV strain signal by AD620 instrumentation amplifier amplifies the signal into 1.5V + 1V, through the V / F converter LM131is converted into frequency signal, signal through the annular transformer T2 from the rotation of the primary coil is transmitted to the static secondary coil, through the casing signal processing circuit for filtering, shaping can be obtained with elastic shaft bear the torque is proportional to the frequency of the signal, the signal for the TTL level, which can provide special two instruments or frequency meter display can also be sent directly to the computer processing. Since the rotary transformer dynamic - static ring between only a few tenths of millimeters gap, coupled with the sensor shaft parts are sealed in the metal shell, forming an effective barrier, thus has the strong anti jamming ability. Some sensors can be divided into physical class, also cannot be divided into chemical class. The majority of sensor is based on physical principles operation. Chemical sensor technology problems, such as reliability, the scale of production possibility, the price problem, to solve this kind of problem, chemical sensor applications will have tremendous growth.
Sensor applications commonly have automatic doors, using the human body infrared microwave to switch the door; the smoke alarm, using smoke sensitive resistor to measure delays concentration, so as to achieve the purpose of alarm; mobile phone, digital camera camera, using an optical sensor to capture images; electronic, mechanical sensor ( conductor strain gage technique ) to the measurement of objects strain gage pressure, so as to achieve the purpose of measuring the weight of the water level alarm; alarm; temperature; humidity alarm; optical alarm.
Intelligent sensor has been widely used in aerospace, aviation, national defense, science and technology and industrial and agricultural production and other fields. For example, the robot in the field has a broad application prospect of intelligent sensor, the robot with human facial and brain function, can perceive various phenomena, to complete a variety of actions. In industrial production, the use of traditional sensor can not for some quality indexes of the product ( e.g., viscosity, hardness, surface finish, composition, color and taste, etc.) for rapid direct measurement and on line control. While the use of intelligent sensor can be directly measured and the quality indexes of the product have the functional relationship between the production of certain quantity ( such as temperature, pressure, flow, etc.). Cygnus company productivity a" glucose watch", its appearance is as same as the ordinary watches, wear it can achieve without pain, without blood, continuous blood glucose test. " Glucose watch" on a painted reagent mat mat, when brought into contact with the skin, the glucose molecule is adsorbed attached to the mat, and with the reagent electrochemical reaction, generate current. Sensor for measuring the current, the processor calculates a current corresponding with the glucose concentration in the blood, and with digital display.
The current status of China is long is the rapid growth of the market, breed increases quickly; high dependence on imports, exports low-end incremental; many manufacturers such as forest, to top brands; general hasten is firm, price drops year by year; core technology hard, on the production of live domestic sensors, main market is the world famous brand occupied.
Function
Often the sensor function and5 human sensory organs to be compared: a photosensitive sensor -- visual sound sensor -- auditory gas sensor -- olfactory chemical sensor, temperature sensor, pressure sensitive -- taste fluid sensor -- touch sensitive element classification: Physics, based on force, heat, light, electricity, magnetic and other physical effects. In chemistry class, based on the chemical reaction principle. Biological class, based on enzymes, antibodies and hormones, such as molecular recognition function. Usually according to its basic perceptual features can be divided into the thermosensitive element, photosensitive devices, gas sensors, force sensors, magnetic sensors, humidity sensors, acoustic sensors, radiation sensitive element, color sensitive components and flavor components such as the ten major categories ( who still had the sensitive element is divided into 46 categories ).
Editor this paragraph characteristics
New sensor features include : miniaturization, digital, intelligent, multi-functional, systematic, networking, it not only promoted the transformation of traditional industries and upgrade, and may also establish a new industry, and in twenty-first Century to become the new economic growth point. Miniaturization is the establishment in the microelectronic mechanical system ( MEMS ) technology on the basis, has been successfully applied in the silicon device made of silicon pressure sensor.
Classification
You can use different perspectives to classify sensors:
Their conversion principle ( sensor the basic physical or chemical effect); their use; their output signal type and the production of their materials and technology. According to the working principle of the sensor, the sensor can be divided into physical and chemical sensor two categories: sensor working principle classification of the physical sensor application is the physical effects, such as the piezoelectric effect, the phenomenon of magnetostrictive, ionization, polarization, thermoelectric, photoelectric, magnetoelectric effect. The measured signal of small changes are converted into electrical signals. Chemical sensors including those by chemical adsorption, electrochemical reaction phenomenon for the causality of sensor, the measured signal is small changes will also be converted to electrical signals. Some sensors can be divided into physical class, also cannot be divided into chemical class. The majority of sensor is based on physical principles operation. Chemical sensor technology problems, such as reliability, the scale of production possibilities, price problem, to solve this kind of problem, chemical sensor applications will have tremendous growth. Common sensor application and working principle are listed in the table below.
The 1sensor according to their uses
Pressure sensitive and force sensor, position sensor liquid level sensor energy sensor speed sensor acceleration sensor radiation sensor thermistor sensor24GHz radar sensor
The 2sensor according to the principles of classification
Vibration sensor humidity sensor magnetic sensor gas sensor vacuum sensor biosensor.
According to the3sensor output signal into the standard classification
The analog sensor -- will be measured by non electrical quantity is converted to an analog electrical signal. Digital sensor -- will be measured by non electrical quantity is converted to digital transmission
Signal ( including direct and indirect conversion ). Taking digital sensor -- will be measured signal is converted into a frequency signal or short periodic signal output (including direct or indirect conversion ). Switch sensor -- when a measured signal reaches a certain threshold value, the sensor output corresponding to a set of low level or a high level signal.
The 4sensor according to the material for the standard classification
On the external factors, all materials will make corresponding, has features of response. They are of those on the outside of the most sensitive material, i.e. those with functional properties of the materials, are used to make the sensitive element of the sensor. From the application point of view of the material can be divided into the following categories: sensor (1) according to the materials used in the classification of polymer metal ceramic mixture (2) according to the physical properties of materials: conductor insulator semiconductor magnetic material (3) according to the crystal structure of material: monocrystalline polycrystalline amorphous materials and adopting new material is closely related to the sensor development, can be summed up in the following three directions: (1) the material known to the exploration of new phenomena, effects and response, and then make them in sensor technology in practical use. (2) to explore new materials, application of the known phenomenon, effects and response to improvement of sensor technology. (3) in the study of new materials based on exploring new phenomenon, new effects and response, and the sensor technology to implement. Modern sensor manufacturing progress depends for sensor technology and new materials and sensitive element of development intensity. Sensor development is a basic trend of semiconductor and dielectric materials and the application of closely related. Table1.2gives some can be used in sensor technology, capable of converting the energy in the form of material.
The 5sensor in accordance with its manufacturing processes classification
Integrated sensor thin thick film sensor ceramic sensor integrated sensor is the standard production of silicon semiconductor integrated circuit technology manufacturing. Usually will be used for initial treatment of measured signals in the parts of the circuit are integrated on the same chip. The film is deposited on the sensor through the dielectric substrate ( substrate ) on the corresponding sensitive materials, thin film formation. Using hybrid process, the same can be part of the circuit substrate manufacturing in. Thick film sensor is the use of the corresponding material slurry, is coated on the ceramic substrate made of, the substrate is usually made of Al2O3, then heat treated, so that the thick film forming. Ceramic sensor using standard ceramic technology or some variant process ( such as the production of sol - gel ). Complete appropriate preparatory operation, has been forming element in high temperature sintering. Thick film and ceramic sensors for the two processes have many common characteristics, in some respects, can think of thick film technology is a variant of ceramic technology. Each technique has its own advantages and disadvantages. As a result of research, development and production of the necessary capital investment is low, and the sensor parameters of high stability and other reasons, using ceramic thick film sensor more reasonable and. ( empty companion network HVAC experts)
The 6sensor according to the purpose of measurement of different classification
Physical type sensor is the use of the substances being measured on certain physical properties change properties to make. Chemical type sensor is the use of the chemical composition, concentration and chemical conversion into electricity quantity of the sensitive element. The biological sensor is the use of a variety of biological or biological properties of matter made of, for detection and identification of organisms within the chemical sensor.
The 7sensor according to the composition of the different classification
The basic sensor: is one of the most basic single conversion device. Combination type sensor: is made up of different single conversion device formed by combining sensor. Application sensor: is the basic type of sensor or combined sensor and other institutions formed by combining sensor.
The 8sensor according to the function and form of different classification
By the form can be divided into active and passive sensor. Active sensor and the function type and reaction type, the sensor of the measured object can emit a detection signal, can detect signal in the measured object changes, or by the detection of signals in the measured object to produce certain effect to form signal. Detection detection signal changes in the way called action type, detection signal generated in response to form called reaction type. Radar and radio frequency range of the detector is the role of examples, and the photoacoustic effect analysis device and laser analyzer is counteractive examples. Passive sensor for receiving the object to be measured is itself generated signals, such as infrared radiation thermometer, infrared imaging device
Characteristic
Static characteristics of sensor
The sensor static characteristic refers to a static input signal, the sensor between input and output have mutual relations. When the input and output are has nothing to do with time, so the relationship between them, whereby the sensor static characteristic can be a free time variables algebraic equation, or to input as the abscissa, the corresponding output as the ordinate and draw the characteristic curve to describe. Characterization of static characteristics of sensor are the main parameters: linearity, sensitivity, hysteresis, repeatability, drift. (1): refers to the sensor linearity between input and output of the actual curve fitting a straight line to the degree of deviation. Defined as in the full range of actual characteristic curve and the fitting line between maximum deviation value and the output value ratio. (2): sensitivity of static characteristics of sensor sensitivity is an important index of. It is defined as the output increment and the increment of the corresponding input increment ratio. S sensitivity. (3): sensor hysteresis in input from small to big ( positive range ) and input from large to small ( the trip ) changes during its input output characteristic curve is not coincidence become hysteresis. For the same size of input signal and output signal, the sensor travel size are not equal, the difference is known as hysteresis difference. (4): reproducibility repeatability refers to the sensor in the input in the same direction as the full range of continuous change for many times, the characteristic curve of the degree of inconsistency. (5): sensor drift drift refers to the input quantity invariable situation, the sensor output changes over time, this phenomenon is called drift. Drift the reason to have two aspects : one is the sensor's structure parameter; two is the surrounding environment ( such as temperature, humidity etc.).
The sensor's dynamic characteristic
Dynamic characteristics, sensor refers to variations in the input, the output characteristics. In practical work, the sensor dynamic characteristics of commonly used it to certain standard input signal in response to said. This is because the sensor on the standard input signal in response to experimental method, and it is a standard input signal and its response to any input signal in response to a relationship, often know the latter can be presumed. The most commonly used standard input signal step and sinusoidal signals of two, so the dynamic performance of the sensor are also commonly used step response and frequency response to express.
Linearity of the sensors
Typically, the actual sensor static characteristic of the output is a curve rather than a straight line. In the practical work, in order to make the instrument has a uniform scale readings, a linear approximation to represent the actual characteristic curve, linearity ( nonlinear error ) is the degree of approximation of a performance index. Fitting a straight line to the selection has many kinds of methods. If the zero input and output connected theory straight line as fitting a straight line; or with the characteristics of each point on the curve of deviation square and minimum theory straight line as the fitting straight line, this fitting straight line is called the least squares fitting a straight line.
The sensor resolution
Resolution refers to the sensor can be sensed by measuring the smallest change capacity. That is to say, if the input from a nonzero value change slowly. When the input changes value does not exceed a certain value, the sensor output does not change, namely the sensor to input volume changes are resolved not to come out. Only when the input volume changes over a resolution, the output will change. Usually the sensor in the full range of each point resolution is not the same, so the full range of commonly used can make the output step change generated input in the largest change value as a measure of resolution index. If the index with the full range of percentage, then known as the resolution. Resolution and stability of the sensor have negative correlation.