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Dec 19 2017

Classification and Functional Application of Sensors

Warm hints: The word in this article is about 2800 and  reading time is about 15 minutes

Introduction

Sensor,also called Transducer, is a kind of detection device,it can receive the measured information and then output them according to a certain rule or other needed form to meet the transport, handling,storage,recording,displaying and controlling of imformation,etc.This is a most comrehensive science popularizing article,sensor has been introducted comprehensively including the definition of sensor,features,types,functions,characteristics and so on here.

Article Core

Most Comprehensive Sicence Popularizing of Sensor (detection device)

Purpose

Fully understand the sensor

English name

sensor

Category

Semiconductor(detection device) 

Function

meet the transport, handling,storage,recording,displaying and controlling of imformation,etc

Feature

miniaturization, digitalization, intellectualization, multi-function, systematization and networking


Catalogs


Catalogs

I.Definition

Intelligent

the purpose

Selection of sensitivity

II.Main Role

Photosensitive

the principle

Frequency Response Characteristics

III.Main Features

Biosensor

the output signal

Linear range

IV.Component of Sensors

Vision

Manufacturing-process

Stability

V.Main function

Displacement

measurement purposes

Accuracy

VI.Common Types

Pressure sensor

constitute

X.Common terms

Resistance

Ultrasonic distance measurement

effecting form

XI.Environmental influence

Frequen conversion

power

 

24GHz-Radar-sensor

VIII.Main characteristic

XII.The selection and range

Weighing sensor

Integrated

temperature

Sensor static

XIII.National stadards

Resistance-strain-gauge

Liquid level

Sensor dynamics

XIV.Technical Characteristics

Piezoresistive sensor

Vacuum sensor

Linearity

Sensor technology and industry characteristics

Thermal resistance

Capacitive level

Sensitivity

Basis & application

Laser

Antimony-electrode acidity

Resolution

Technology intensive and investment intensive

Holzer sensor

Acid, alkali, salt

IX.Principle of selection

Industrial decentralization and product dispersion

Temperature

Conductance



Wireless temperature

VII.Main classification




Introduction

I.Definition

Sensor,also called Transducer, is a kind of detection device,it can receive the measured information and then output them according to a certain rule or other needed form to meet the transport, handling,storage,recording,displaying and controlling of imformation,etc. According to the national stadards GB7665-87, Sensors, which can receive the measured information and convert them into an available signal device, are made of sensory unit or interface element.

 School Enterprise Alliance of China Internet of Things thinks that the existence and development of sensor is to let the object has the sense of touch,taste, smell and so on, let the object lives up slowly.

 In the New Webster's Dictionary, sensor is defined as a device that receives power from a system then sends the power to the another system in another form.


II.Main Role

In order to get information from outside,people have to use sense organ. Just use the sense organ, however, is not enough in researching natural phenomenen and laws and production activities. Now sensor is come in handy. Therefore,sensor is the extension of the human five senses,which is also named the electric five-senses.

electric five-senses.

The world began into information era with the coming of revolution of the world new technology. In the process of using information,the first problem we need to solve is  to get accurate and reliable information. Sensor is the main way to get them.

In the process of modern industrial production especially the automation ,various sensors are used to monitor and control the various parameters in the production process to make devices work in a normal or optimal state then make the products achieve the best quality. Therefore, it also can be said, modern production has also lost its foundation without a large number of excellent sensors.

In the research of basic subject,sensors have a more prominent position. The development of modern science and technology has entered many new fields such as observing the vast universe of thousands of light years at the macroscopically, observing the particle world which is smaller than FM at the microcosimic, observing the evolution of celestial bodies for hundreds of thousands of years longgitudinally, moment response until s. What's more, there have also been a variety of extreme technical studies that have an important role in deepening material understanding, developing new energy and new materials like ultra high temperature, ultra-low temperature, ultra high pressure, ultra high vacuum, super strong magnetic field, ultra weak magnetic field and so on. Obviously, it's impossible to get a lot of information without mutual adaptive sensor.  Many obstacles in basic scientific research lie in the difficulty of obtaining object information. However, some new mechanisms and high-sensitivity detection sensors often lead to breakthroughs in the field. The development of some sensors is often a pioneer in the development of some marginal disciplines. Sensors have long penetrated into the most extensive fields, such as industrial production, Cosmos development, marine exploration, environmental protection, resource investigation, medical diagnosis, bioengineering, even cultural relics protections and ect.It can be no exaggeration to say that almost every modern project can not be separated from all kinds of sensors, from vast space to vast oceans and even complex engineering systems. 

It can be seen obviously that the sensor plays a important role  in the economic developing and promoting social progress. All countries of the world have attached great importance to the development of this field. It is believed that in the near future, sensor technology will have a leap to reach a new level that is commensurate with its important status.


III.Main Features

The characteristics of sensors include: miniaturization, digitalization, intellectualization, multi-function, systematization and networking. It not only promotes the transformation and upgrading of traditional industries, but also establishes new industries, thus becoming a new economic growth point in twenty-first Century. Microminiaturization is based on the microelectronic mechanical system (MEMS) technology and has been successfully applied to silicon pressure sensors.


IV.Component of Sensors

As the following picture shows, The sensor is usually composed of four parts, such as sensitive element, conversion element, transform circuit and auxiliary power supply.

the component of sensor


V.Main function

The function of the sensor is often compared with the 5 major sensory organs of the human being:

Photosensor -- vision

Acoustic sensor -- hearing

Gas sensor - olfaction

Chemical sensors - taste sense

Pressure sensitive, temperature-sensitive, fluid sensor - tactile


sensor image

Classification of sensitive elements:

The physical class is based on the physical effects of force, heat, light, electricity, magnetism, and sound.

Chemical, based on the principle of chemical reaction.

Biological classes, based on molecular recognition of enzymes, antibodies, and hormones.

Usually according to its basic cognitive function can be divided into a heat sensitive element, a photosensitive element, gas sensor, force sensor, Ci Min element, humidity sensor, acoustic sensor, radiation sensitive element, color sensitive components and taste sensitive components etc. ten categories (some had the sensitive element is divided into 46 categories).


Detail

VI.Common Types

6.1.Resistance

Resistive sensor is a device that is transformed into physical quantities such as displacement, deformation, force, acceleration, humidity, temperature and so on. There are resistance strain sensors, such as resistance strain type, piezoresistive type, thermal resistance, thermal sensitive, gas sensitive, humidity sensitive and so on.


6.2.Frequency Conversion Power Sensor

Frequency conversion power sensor


Thermal resistance

Thermal resistance measurement is based on the increase of the resistance value of metal conductors with the increase of temperature to measure the temperature. Most of the thermal resistors are made of pure metal. At present, platinum and copper are the most widely used. In addition, the thermal resistance has been made with nickel, manganese and rhodium.

The thermoelectric resistance sensor is mainly used the characteristics that the resistace value will change according to the temperature to measure the temperature  and its related parameters . This kind of sensor is more suitable in the situation where the temperature detection precision is high. The widely used thermal resistance materials are platinum, copper and nickel. They have the characteristics of large resistance, high temperature coefficient, good linearity, stable performance, wide temperature range and easy processing. It is used to measure the temperature in the range of -200 C ~ +500 C.

Thermoelectric resistance sensor classification:

a.NTC thermal resistance sensor:

This kind of sensor is a negative temperature coefficient sensor, that is, the resistance of the sensor decreases with the increase of temperature.

b.PTC thermal resistance sensor:

This kind of sensor is a positive temperature coefficient sensor, that is, the resistance value of the sensor increases with the increase of temperature.


6.3.Laser


Laser sensor

A sensor that is measured by laser technology. It is composed of laser, laser detector and measuring circuit. Laser sensor is a new type of measuring instrument. Its advantage is that it can achieve non-contact remote measurement, with high speed, high accuracy, wide range, and strong ability to resist light and electricity. When the laser sensor works, the laser emission diode is used to target the laser pulse at the target. After the target is reflected, the laser is scattered in all directions. Part of the scattered light returns to the sensor receiver and is received by the optical system to the avalanche photodiode. Avalanche photodiode is an optical sensor with internal amplification function, so it can detect extremely weak light signals and transform them into corresponding electrical signals.

The non-contact distance measurement can be achieved by using the characteristics of high direction, high monochromatic and high brightness of laser. Laser sensors are usually used for measuring physical quantities such as length (ZLS-Px), distance (LDM4x), vibration (ZLDS10X), speed (LDM30x), azimuth and so on. They can also be used for detection and monitoring of air pollutants.


6.4.Holzer Sensor

Holzer sensor

Holzer sensor is a magnetic field sensor based on Holzer effect. It is widely used in industrial automation technology, detection technology and information processing. The Holzer effect is the basic method to study the properties of semiconductor materials. The Holzer coefficient measured by the Holzer effect test can determine the important parameters of the conductive type, carrier concentration and carrier mobility of the semiconductor materials.

Holzer sensor can be devided into two types:

a. Linear Holzer Sensor. The linear Holzer sensor is composed of a Holzer element, a linear amplifier and a emitter follower, which outputs the analog quantity.

b. Switched Holzer Sensor. Switch type voltage regulator, Holzer Holzer by the sensor element, differential amplifier, Schmitt trigger and output stage and its digital output.

The Holzer voltage varies with the intensity of the magnetic field. The stronger the magnetic field, the higher the voltage, the weaker the magnetic field and the lower the voltage. Holzer voltage is very small, usually only a few milli volts, but by amplifying the amplifier in IC, the voltage can be amplified enough to output strong signals. If the Holzer integrated circuit plays a sensing role, a mechanical method is needed to change the magnetic field strength. The method shown below is using a rotating impeller as a switch to control magnetic flux. When the impeller blade is in the air gap between the magnet and the Holzer integrated circuit, the magnetic field deviates from the integrated chip, and the Holzer voltage vanishes. In this way, the change of output voltage of Holzer integrated circuit can indicate a certain position of the impeller driving shaft. With this principle, the ignition timing sensor of the integrated circuit chip of Holzer can be used. The Holzer effect sensor is a passive sensor, and it has to have an additional power to work. This feature enables it to detect the operation of low speed.


6.5.Temperature Sensor


Temperature sensor

1. Room temperature/tube temperature sensor: room temperature sensor is used to measure indoor and outdoor ambient temperature, and tube temperature sensor is used to measure the wall temperature of evaporator and condenser. The room temperature sensor and the tube temperature sensor have different shapes, but the temperature characteristics are basically the same. According to the temperature characteristics, the room temperature sensor used in the United States has two types: the 1. constant B value is 4100K + 3%, the reference resistance is 25 C and the resistance 10K Omega 3%. Resistance tolerance at 0 and 55 centigrade is about 7%, and below 0 C and above 55 degrees, resistance tolerance will vary for different suppliers. The higher the temperature, the smaller the resistance, the lower the temperature, the greater the resistance. The farther away from 25 C, the greater the tolerance range is.

2. Exhaust temperature sensor: the exhaust temperature sensor is used to measure the exhaust temperature at the top of the compressor. The constant B value is 3950K + 3%, and the base resistance is 90 C, corresponding to resistance 5K ohm + 3%.

3. Module temperature sensor: the module temperature sensor is used to measure the temperature of the frequency conversion module (IGBT or IPM). The type of the temperature sensing head is 602F-3500F, and the base resistance is 25 degrees, corresponding to the resistance 6K ohm + 1%. The corresponding resistance values of several typical temperatures are: -10 C ~ (25.897 ~ 28.623) K ohm; 0 C to 16.3248 ~ 17.7164 K ohm; 50 C to 2.3262 ~ 2.5153 K ohm; 90 C to 0.6671 to 0.7565 K ohm.

There are many kinds of temperature sensors, often used with thermal resistance: PT100, PT1000, Cu50, Cu100; thermocouples: B, E, J, K, S and so on. The temperature sensor is not only a wide variety, but also the combination of various forms, should choose the appropriate products according to different places.

The principle of temperature measurement: according to the principle of electric resistance and thermocouple's potential changing with temperature, we can get the temperature value that we need to measure.


6.6. Wireless Temperature Sensor

The wireless temperature sensor turns the temperature parameter of the control object into the electrical signal, and sends the wireless signal to the receiving terminal, and carries out the detection, adjustment and control of the system. It can be directly installed in the junction box of the general industrial thermal resistance and thermocouple, which is integrated with the field sensor components. It is usually used in conjunction with wireless relay, receiving terminal, communication serial port, electronic computer and so on, which not only saves the compensation wires and cables, but also reduces the distortion and interference of signal transmission, thus obtaining the high-precision measurement results.

Wireless temperature sensors are widely used in chemical, metallurgical, petroleum, electricity, water treatment, pharmaceutical, food and other automation industries. For example: temperature acquisition of high voltage cable; temperature acquisition underwater environment; temperature acquisition on moving objects; spatial transmission of sensor data is not easy to connect through; in order to reduce the cost of wiring scheme of data acquisition used simple data; measurement occasions without AC power supply; portable non fixed place measurement data.


6.7. Intelligent Sensor


Intelligent Sensor

The function of intelligent sensor is simulated by simulating the coordination action of human's sense organs and brain, combining with the research and practical experience of long term test technology. It is a relatively independent intelligent unit. Its appearance has reduced the harsh requirements of the original hardware, and the performance of the sensor can be greatly improved by software help.

a. Information storage and transmission. With the rapid development of the intelligent distributed control system (SmartDistributedSystem), the intelligent unit requires communication function and two-way communication in the form of digital communication network. This is also one of the key signs of smart sensors. The intelligent sensor implements various functions by testing data transmission or receiving instructions. Such as the setting of the gain, the setting of compensation parameters, the setting of internal check parameters, the output of the test data and so on.

b. Self compensation and calculation function -- engineers and technicians engaged in sensor development for many years have been doing a lot of compensation for temperature drift and output nonlinearity of sensors, but they have not fundamentally solved the problem. The self compensation and calculation function of the intelligent sensor has opened a new way for the temperature drift and nonlinear compensation of the sensor. So, relax the sensor processing precision requirement, as long as we can ensure the repeatability of sensor, using microprocessor signal test through software calculation by using the calculation method and the difference of multiple fitting to compensate the drift and nonlinear, so as to obtain more accurate measurement results of pressure sensor.

c. Self test, self calibration and self diagnosis function -- regular sensors need regular inspection and calibration to ensure that they are sufficiently accurate when used normally. These jobs generally require sensors to be removed from the field of use to the laboratory or inspection department. It is not timely to diagnose the abnormal appearance of the on-line measuring sensor. The use of intelligent sensors is greatly improved. First, self detection is carried out when the diagnostic function is connected to the power supply, and the diagnostic test is used to determine the failure of the component. Secondly, it can be corrected online according to the time of use, and the microprocessor uses the measurement characteristic data in EPROM to check and proofread.

d. Complex sensitive function - observation of the natural phenomena around them, the common signals are sound, light, electricity, heat, force, chemistry and so on. Sensitive element measurements are generally measured in two ways: direct and indirect measurements. The intelligent sensor has a complex function, which can measure a variety of physical quantities and chemical quantities at the same time, and gives information that can reflect the law of material motion in a more comprehensive way.


6.8. Photosensitive Sensor

The photosensitive sensor is one of the most common, its variety, mainly include: photodiode, photomultiplier tube, photosensitive resistor, photosensitive triode, solar battery, an infrared sensor and an ultraviolet sensor, photoelectric sensor, optical fiber sensor, CCD and CMOS color image sensor etc.. Its sensitive wavelength is near the wavelength of visible light, including infrared wavelengths and ultraviolet wavelengths. Optical sensors are not only limited to the detection of light, but also can be used as components to detect other sensors, and detect many non electric quantities. Optical sensor is one of the most widely used sensors at present. It plays a very important role in automatic control and non electric measurement technology. The simplest photosensitive sensor is a photosensitive resistor, which produces a current when the photon is impacted at the junction.


6.9. Biosensor

Biosensor

Biosensor is a bioactive material (enzyme, protein, DNA, antibody, antigen, biofilm) and the organic combination of physical and chemical transducer is a cross discipline, is the development of biotechnology essential for an advanced detection method and monitoring method, fast and trace analysis of molecular level and also the material. All kinds of biosensors are the following: the common structure includes one or several kinds of biological active material (biofilm) and the biological activity of the expression of signal conversion into electrical signals in the physical or chemical transducer (sensor), the two together, with modern micro electronics and automation instrument technology and biological signal a variety of processing, biological sensors can be used to analyze device, instrument and system.

a. The Principle of biosensors

The substance to be determined by diffusion into the bioactive materials by molecular identification, biological reaction, and then the corresponding information produced by physical or chemical transducer can be transformed into quantitative and signal processing, and then by two instrumentation amplifier and the output, you can know the concentration to be measured.

b. The Classification of biosensors

According to the classification of living substances used in their receptors, it can be divided into: microbial sensors, immunosensors, tissue sensors, cell sensors, enzyme sensors, DNA sensors and so on.

According to the principle of sensor device detection, it can be divided into: thermosensitive biosensor, field effect transistor biosensor, piezoelectric biosensor, optical biosensor, acoustic channel biosensor, enzyme electrode biosensor, mediator biosensor and so on.

According to the classification of the types of interaction of biosensitive substances, it can be divided into two types: affinity and metabolism.


6.10. Vision Sensor

Vision Sensor

Visual sensor refers to the ability to capture thousands of pixels from a whole image, which is usually measured by the resolution and the number of pixels.

The visual sensor has thousands of pixels that capture light from an entire image. The clarity and fineness of the image is usually measured by the resolution, and is represented by the number of pixels.

After capturing the image, the visual sensor compares it with the datum image stored in memory to make an analysis. For example, if the visual sensor is set to identify the machine parts that correctly insert eight bolts, the sensor knows that it should reject only seven bolts, or the parts whose bolts are not aligned. In addition, no matter where the machine parts are located in the field of view, no matter whether the component rotates in the 360 degree range, the visual sensor can make a judgment.

a. Application

The low cost and ease of use of visual sensors have attracted machine designers and process engineers to integrate them into all kinds of applications that once relied on artificial, multiple photoelectric sensors or not. The industrial applications of visual sensors include inspection, measurement, measurement, orientation, flaw detection and sorting. Here are some examples of application:

In the automobile assembly plant, whether the bead is applied to the frame of the car door is continuous or not, and whether it has the correct width.

In the bottling plant, check the bottle cap to be sealed correctly, whether the filling level is correct, and no foreign objects fall into the bottle before the seal is sealed.

In the packing line, make sure that the correct packing labels are attached to the correct position.

In the drug packaging line, there is a test for whether there is a broken or missing tablet in the blister package of aspirin tablets.

In the metal stamping company, the stamping parts are tested at more than 150 pieces per minute, more than 13 times faster than the manual inspection.


6.11. Displacement Sensor


Displacement sensor

The displacement sensor is also called a linear sensor, which converts the displacement into a transducer of electricity. The displacement sensor is a linear device belonging to the metal induction sensor, is the role of the measured physical quantity is converted to electricity which is divided into a type of inductance displacement sensor, capacitive displacement sensor, photoelectric sensors, ultrasonic sensors, Holzer type displacement sensor.

There are many physical quantities (such as pressure, flow rate and acceleration) in the transformation process, which often need to be transformed into displacement first, then the displacement is converted into electricity. Therefore, the displacement sensor is a kind of important basic sensor. In the process of production, the measurement of displacement is generally divided into two kinds: measuring the size of the object and the mechanical displacement. The mechanical displacement includes line displacement and angular displacement. The displacement sensors can be divided into two types, which are analog and digital, according to the variation of measured variables. The simulation can be divided into two kinds of material type (such as self generating type) and structure type. The most commonly used displacement sensors are analog structural type, including potentiometer displacement sensor, inductive displacement sensor, synchro, capacitive displacement sensor, eddy current displacement sensor, Holzer displacement sensor and so on. An important advantage of the digital displacement sensor is that it is convenient to send the signal directly into the computer system. This kind of sensor has been developed rapidly and widely used.


6.12.Pressure Sensor

The pressure sensor is introduced in industrial practice is the most commonly used one kind of sensor, which is widely used in various industrial control environment, involving water conservancy and hydropower, railway transportation, intelligent buildings, production automation, aerospace, military, petrochemical, oil, electric power, shipbuilding, machine tools, plumbing and other industries.


6.13.Ultrasonic Distance Measurement

Ultrasonic distance measuring sensor using the ultrasonic echo principle, using the precise time difference measurement technique, between sensor and target distance using small angle, small blind ultrasonic sensor has the advantages of accurate measurement, non-contact, waterproof, anti-corrosion, low cost and other advantages, it can be used for liquid level, material level detection, characteristic level, material position detection method, can ensure that there is a bubble or a large rock on the surface, not easy to detect a stable output, echo under the condition of application: liquid level, material level, material level detection, industrial process control etc.


6.14. 24GHz Radar Sensor

 

24GHz Radar sensor

24GHz radar sensor using high frequency microwave to measure velocity, distance, motion, direction and azimuth angle information, the design of planar microstrip antenna has the characteristics of small volume, light weight, high sensitivity, strong stability, widely used in intelligent transportation, industrial control, security, intelligence, sports and other industries Home Furnishing. The Ministry of industry and information technology in November 19, 2012 officially released the "Ministry of industry and information issued a notice of 24GHz band short distance vehicle radar equipment using frequency" (the Ministry of no 2012 No. 548), clearly put forward the 24GHz band short distance vehicle radar equipment as Che Zailei reached equipment specification.


6.15.Integrated Temperature Sensor

An integrated temperature sensor consists of a temperature measuring probe (a thermocouple or a thermal resistance sensor) and a two wire solid electronic unit. The temperature measuring probe is installed in the junction box directly in the form of solid module, so as to form an integrated sensor. The integrated temperature sensor is generally divided into two types: thermal resistance and thermocouple type.

The thermal resistance temperature sensor is composed of a reference unit, a R/V conversion unit, a linear circuit, a reverse protection, a current limiting protection, and a V/I conversion unit. After measuring and amplifying the heat resistance signal, the linear relation between temperature and resistance is compensated by a linear circuit. After the V/I conversion circuit, a constant current signal with a linear relationship between the temperature and the measured temperature is output, which is 4 to 20mA.

The thermocouple temperature sensor is generally composed of reference source, cold terminal compensation, amplification unit, linearization, V/I conversion, fault couple processing, reverse connection protection, current limiting protection and other circuit units. It amplifies the thermoelectric force generated by thermocouple through the cold end, and then removes the nonlinear error of the thermoelectric potential and temperature from the linear circuit, and finally amplifies it to a 4 to 20mA current output signal. In order to prevent the temperature failure caused by the broken wire of the electric couple in the measurement of the thermocouple, a power break protection circuit is also set in the sensor. When the thermocouple has broken wire or bad connection, the sensor will output the maximum value (28mA) to make the instrument cut off the power. The integrated temperature sensor has the advantages of simple structure, saving lead, large output signal, strong anti-interference ability, good linearity, simple display instrument, solid module anti-seismic and moisture-proof, reverse connection protection and current limiting protection, reliable operation and so on. The output of the integrated temperature sensor is a unified 4 to 20mA signal; it can be used to match the microcomputer system or other conventional instruments. It can also be used to make explosion-proof or fireproof type measuring instruments.


6.16.Liquid Level Sensor

a. Floating ball level sensor

The floating ball level sensor is composed of a magnetic floating ball, a measuring tube, a signal unit, an electronic unit, a junction box and an installation part. The proportion of the general magnetic floating ball is less than 0.5, and it can drift above the liquid surface and move up and down the measuring tube. A measuring element is installed inside the catheter. It can convert the measured liquid level signal to a resistance signal which is directly proportional to the liquid level change under the external magnetic force, and convert the electronic unit to 4 to 20mA or other standard signal output. The sensor is a module circuit. It has the advantages of acid resistance, moisture-proof, shockproof and anti-corrosion. The circuit contains constant current feedback circuit and internal protection circuit, so that the maximum output current can not exceed 28mA, so that it can reliably protect the power and make the two meter not damaged.

b.Floating level sensor

The float type liquid level sensor is to change the magnetic floating ball into a buoy, which is designed according to the Archimedes buoyancy principle. A buoy liquid level sensor uses a tiny metal membrane strain sensing technique to measure the liquid level, boundary, or density of a liquid. It can perform routine setting operations through the field buttons at work.

c.Static pressure or liquid level sensor

The sensor works by using the measurement principle of liquid static pressure. It usually uses silicon pressure sensor to convert the measured pressure into electrical signal, then amplifies and compensates the circuit by amplifying circuit, and finally outputs it in a current mode of 4 ~ 20mA or 0 ~ 10mA.


6.17. Vacuum Sensor

Vacuum sensor, using advanced silicon micromachining technology production, the absolute pressure transmitter with integrated silicon pressure sensors made as a core component of the sensor, the vacuum reference using silicon direct bonding or silicon Pyrex electrostatic bonding formed by the pressure chamber, and a series of stress free package technology and precise temperature compensation technology, which has outstanding advantages of good stability, high accuracy of measurement and control, applicable to a variety of situations in the absolute pressure.

a. feature and application

Using low range chip vacuum absolute pressure package, the product has high overload capacity. The chip is separated by vacuum filling silicon oil, and the transition pressure of stainless steel thin film is transferred. It has excellent dielectric compatibility. It is suitable for the measurement of the vacuum pressure of most of 316L gas stainless steel liquids. Vacuum measurement and control for low vacuum in various industrial environments.


6.18. Capacitive Level Sensor

Capacitive level sensor is suitable for industrial enterprises to measure and control the production process in production process. It is mainly used for remote measurement and indication of liquid level or granular solid level of conductive and non conductive media.

The capacitive liquid level sensor is composed of capacitive sensor and electronic module circuit. It is based on two wire system 4 to 20mA constant current output. After conversion, it can be output by three or four lines. The output signal is 1 ~ 5V, 0 ~ 5V, 0 ~ 10mA standard signal. The capacitance sensor consists of an insulating electrode and a cylindrical metal container equipped with a measuring medium. When the material position rises, the dielectric constant of the non conductive material is obviously smaller than the dielectric constant of the air, so the capacitance varies with the change of the material height. The module circuit of the sensor consists of the reference source, the pulse width modulation, the conversion, the constant current amplification, the feedback and the current limiting. The advantages of measuring with the principle of pulse width modulation are low frequency, radio frequency interference, good stability, good linearity and no apparent temperature drift.


6.19. Antimony Electrode Acidity Sensor

Antimony electrode acidity sensor is an industrial online analysis instrument integrating PH detection, automatic cleaning and electrical signal conversion. It is a pH measurement system composed of antimony electrode and reference electrode. In the acid solution, three oxidation two antimony oxide will form on the surface of antimony electrode, so that potential difference between metal antimony and three oxidation two sb will be formed. The magnitude of the potential difference depends on the concentration of the three oxidized two antimony, which corresponds to the moderate amount of the hydrogen ion in the acid solution. If the moderation of antimony, three oxidation two antimony and water solution is 1, the electrode potential can be calculated by the nantst formula.

The solid module circuit of the antimony electrode acidity sensor consists of two parts. In order to ensure the safety of the field, the power supply is supplied by the AC 24V for the two meter. In addition to providing the driving power for the cleaning motor, the power supply should be converted to the corresponding DC voltage by the current conversion unit for use in the converter circuit. The second part is to measure the sensor circuit. It amplifies the reference signal and the PH acidity signal from the sensor to the slope adjustment and location adjustment circuit, so as to reduce the internal resistance of the signal and adjust it. The amplified PH signal is superimposed with the temperature compensated signal and then converted into the conversion circuit. Finally, the 4 to 20mA constant current signal corresponding to the pH value is output to the two time meter to display and control the pH value.


6.20. Acid, Alkali, Salt Concentration Sensor

Acid, alkali, and salt concentration sensors determine the concentration by measuring the conductivity of the solution. It can continuously detect the concentration of acid, alkali and salt in the aqueous solution in the process of industry. This sensor is mainly used in the process of boiler feed water treatment, chemical solution preparation and environmental protection and other industrial production processes.

The principle of acid, alkali and salt concentration sensor is that in a certain range, the concentration of acid and alkali solution is proportional to its electrical conductivity. Therefore, as long as the measurement of the size of the conductivity of the solution can be found, the concentration of acid and alkali can be found. When the measured solution flows into a special conductance pool, if the electrode polarization and the distributed capacitance are ignored, it can be equivalent to a pure resistance. When a constant voltage alternating current flows through, the output current is linearly related to the conductivity, and the conductivity is proportional to the acid and alkali concentration in the solution. So as long as the current of the solution is measured, the concentration of acid, alkali and salt can be calculated.

The acid, alkali and salt concentration sensors are mainly composed of the conductance pool, the electronic module, the display head and the shell. The electronic module circuit is composed of an excitation power supply, an electric conduction pool, an electric conduction amplifier, a phase sensitive rectifier, a demodulator, a temperature compensation, an overload protection and a current conversion unit.


6.21. Conductance

It is a flow meter (integrated sensor) indirectly measuring ionic concentration by measuring the conductance of solution. It can continuously detect the conductivity of aqueous solutions in industrial process online.

Because the electrolyte solution is the same as the metal conductor, the electric current flows through the electrolyte solution, which has a resistance effect and is in accordance with Ohm's law. But the resistance temperature characteristic of the liquid is opposite to the metal conductor, and it has the characteristic of negative temperature. In order to distinguish from metal conductors, the electrical conductivity of the electrolyte solution is expressed by the conductance (the reciprocal of resistance) or the conductivity (the reciprocal of the resistivity). When two mutually insulated electrodes are composed of a conductance pool, a current loop is formed if the solution is placed in the middle of the cell, and the constant voltage alternating current is formed. If the size of the voltage and the size of the electrode are fixed, there is a certain function relationship between the circuit current and the electrical conductivity. In this way, the electric current flowing through the solution can be measured and the conductivity of the solution can be measured. The structure and circuit of the conductance sensor are the same as the acid, alkali and salt concentration sensors.


See the Following Video: 


VII.Main classification

7.1. Accoding to the purpose

Pressure-sensitive and force sensitive sensors, position sensors, liquid level sensors, energy consumption sensors, speed sensors, acceleration sensors, radiation sensors and thermosensitive sensors.

7.2. According to the principle

Vibration sensor, humidity sensor, magnetic sensor, gas sensor, vacuum sensor, biosensor, etc.

7.3.According to the output signal

Analog sensors: conversion of measured non electrical quantities into analog electrical signals.

Digital sensors: conversion of measured non electrical quantities into digital output signals (including direct and indirect conversion).

Taking digital sensor: the output will be measured signal into frequency signal or short periodic signals (including direct or indirect conversion).

Switch sensor: when a measured signal reaches a certain threshold, the sensor outputs a set of low level or high level signal accordingly.

7.4. According to the manufacturing process


integrated sensor

The integrated sensor is made by standard technology for producing silicon based semiconductor integrated circuits. Some of the circuits that are used for preliminary processing of the measured signals are also integrated on the same chip.

The film sensor is formed by the film deposited on the substrate (substrate) and the film of the corresponding sensitive material. When the mixing process is used, part of the circuit can also be made on this substrate.

Thick film sensor is made from the slurry of corresponding material and coated on ceramic substrate. The substrate is usually made of Al2O3, and then heat treated to make thick film forming.

Ceramic sensors are produced by a standard ceramic process or a variety of varieties (sol, gel, etc.).

After the proper preparative operation is completed, the formed components are sintered at high temperature. There are many common characteristics between the two processes of thick film and ceramic sensor. In some respects, it is considered that the thick film process is a variant of the ceramic process.

Each technology has its own advantages and disadvantages. Due to low capital investment and high stability of sensor parameters, ceramic and thick film sensors are more reasonable.

7.5. According to the measurement purposes

A physical sensor is made of a characteristic change in some physical properties of the measured material.

Chemical sensors are made of sensitive elements that can convert chemical components, concentration, and other chemical quantities into electrical quantities.

A biosensor is a sensor made from a variety of biological or biological properties to detect and identify the chemical constituents of the organism.

7.6.According to the constitute

Basic sensor: one of the most basic single transformation devices.

Combined sensor: a sensor composed of a combination of different single transformation devices.

Applied sensor: a sensor composed of a basic type sensor or a combined sensor and a combination of other mechanisms.

7.7. According to the effecting form

It can be divided into active and passive sensors. The active sensor has the function of action and counteraction. The sensor can send out certain detection signal to the detected object, detect the change of the detected signal in the tested object, or form a signal by the detection signal producing some effect in the tested object. The mode of detecting the change of the signal is called the action type, and the response is detected and the form of the signal is called the reaction type. Radar and radio frequency range detector are the example of action type, and the photoacoustic effect analysis device and the laser analyzer are counteracting examples.

Passive sensors only receive signals generated by the measured object itself, such as infrared radiometric thermometer, infrared camera and so on.


VIII.Main characteristic

8.1. Sensor static

Sensor static

The static characteristic of the sensor refers to the static input signal, and the relationship between the output of the sensor and the input amount. Because the input and output are independent of time, the relationship between them, namely sensor static characteristics available a time-dependent algebraic equation, or input as abscissa, the output characteristic curve and the corresponding longitudinal coordinate and draw to describe. The main parameters of the static characteristic of the sensor are linearity, sensitivity, hysteresis, repeatability, drift and so on.

a. Linearity: the degree that the actual relation curve between the output of the sensor and the input quantity deviates from the fitting line. It is defined as the ratio of the maximum deviation value between the actual characteristic curve and the fitting line within the range of the full range and the output value of the full range.

b. Sensitivity: sensitivity is an important indicator of the static characteristics of the sensor. It is defined as the ratio of the increment of the output amount to the increment of the corresponding input amount that causes the increment. S is used to express sensitivity.

sensor 

c. Delay: sensor in the input from the input (positive stroke) and from large to small (reverse stroke) changes during the input and output characteristic curves do not coincide with the phenomenon become sluggish. For the input signal of the same size, the positive and backward stroke output signal of the sensor is not equal, and the difference is called the lag difference.

d. Repeatability: repeatability refers to the degree that the characteristic curves of the sensor are inconsistent when the input quantity is continuously changed in the same direction in the same direction.

e.Drift: the drift of the sensor means that the output of the sensor varies with time when the input is constant, and this phenomenon is called drift. There are two reasons for the drift: one is the structure parameters of the sensor, and the two is the surrounding environment (such as temperature, humidity, etc.).

f.Resolution: when the input of a sensor increases from zero to zero, an observable change occurs when the output exceeds a certain increment. The increment of input is called the resolution of the sensor, that is, the minimum input increment.

g. Threshold: when the input of sensor increases slowly from zero, a change of output is observed after reaching a certain value. This input value is called the threshold voltage of sensor.


8.2.Sensor Dynamics

The so-called dynamic characteristics are the characteristics of the output of the sensor when the input is changed. In practical work, the dynamic characteristics of the sensor are often used to express the response of the sensor to some standard input signals. This is because the response of sensor to standard input signal is easy to be obtained by experimental method, and there is a certain relationship between its response to standard input signal and its response to any input signal. It is often known that the former can predict the latter. The most commonly used standard input signals have two kinds of step signal and sinusoidal signal, so the dynamic characteristics of the sensor are also usually expressed by step response and frequency response.


8.3.Linearity

In general, the output of the actual static characteristic of the sensor is a curve rather than a straight line. In practice, in order to make the instrument have uniform scale reading, a fitting line is commonly used to represent the actual characteristic curve and linearity (nonlinear error), which is a performance index of this approximation degree.

There are many methods for the selection of fitting lines. For example, a theoretical straight line connected with zero input and full scale output points as a fitting line, or a theoretical straight line which is the least square deviation of every point on the characteristic curve as the fitting line, this fitting line is called the least square method to fit the straight line.


8.4.Sensitivity

Sensitivity refers to the ratio of sensor output variation of Y values in the steady state under the condition of input change delta X.

It is the slope of the output of an input characteristic curve. If the output and input of the sensor have a linear relationship, the sensitivity S is a constant. Otherwise, it will change with the change of the input.

The dimension of sensitivity is the ratio of the dimension of output and input. For example, a displacement sensor, when the displacement changes 1mm, the output voltage changes to 200mV, the sensitivity should be expressed as 200mV/mm.

At the same time as the output of the sensor and the dimension of the input quantity, the sensitivity can be understood as the magnification.

In order to improve the sensitivity, a higher measurement precision is obtained. But the higher the sensitivity, the narrower the measurement range and the worse the stability.


8.5. Resolution

Resolution refers to the ability of the sensor to feel the smallest change in measurement. That is to say, if the amount of input changes slowly from a non zero value. When the input change value does not exceed a certain value, the output of the sensor will not change, that is, the change in the input of the sensor is indistinguishable. The output will change only when the change of the input amount exceeds the resolution.

Usually, the resolution of each point is not the same in the full range of sensors. Therefore, the maximum change value of input volume in the full scale can be used to measure the resolution. If the above index is expressed as a percentage of full range, it is called resolution. There is a negative correlation between the resolution and the stability of the sensor.


IX.Principle of selection

To carry out a specific measurement work, first of all, we should consider the principle of the sensor, which needs to be analyzed after many factors can be determined. Because, even if it is to measure the same physical quantity, also has a variety of sensor principle for selection, sensor which principle is more suitable, the need according to the characteristics and conditions for the use of the measuring sensor is considered following some specific problems: the range of the size of the measured position of the sensor; volume measurement; way contact or non-contact; extraction method of signal, cable or non contact measurement; sensor source, domestic or imported, the price can bear, or developed.

After considering the above problems, we can determine what type of sensor to choose, and then consider the specific performance indicators of the sensor.


9.1.Selection of Sensitivity

Usually, in the linear range of the sensor, the better the sensitivity of the sensor is. Because only when the sensitivity is high, the value of the output signal corresponding to the measured change is relatively large, which is beneficial to the signal processing. We should pay attention to that the sensitivity of the sensor is high, and the external noise which is irrelevant to the measurement is also easy to mix. It will also be amplified by the amplification system, which will affect the accuracy of the measurement. Therefore, it is required that the sensor itself should have a high signal to noise ratio and minimize the interference signal introduced from the outside world.

The sensitivity of the sensor is directional. When the measurement is a one-way quantity and has a high requirement for its directivity, we should choose other direction sensitive sensors. If the measurement is multi-dimensional vector, then the smaller the cross sensitivity of the sensor is, the better.


9.2. Frequency Response Characteristics

The frequency response characteristics of the sensor determine the range of the measured frequency, and must remain undistorted in the range of the allowed frequency. In fact, the response of the sensor always has a fixed delay, and it is hoped that the shorter the better the delay time is. The higher the frequency response of the sensor, the wider the frequency range of the measurable signal. In dynamic measurement, the response characteristics of the signal should be based on the characteristics of the signal (steady, transient, random, etc.), so as to avoid excessive error.


9.3.Linear Range

The linear range of the sensor is the range that the output is proportional to the input. In theory, in this range, the sensitivity remains fixed. The wider the linear range of the sensor is, the larger the range is, and it can ensure a certain measurement accuracy. When the sensor is selected, it is first to see if the range of the sensor meets the requirements when the type of sensor is determined. But in fact, any sensor can not guarantee the absolute linearity, and its linearity is relative. When the required measurement accuracy is relatively low, within a certain range, the sensor with smaller nonlinear error can be regarded as linear, which will bring great convenience to measurement.


9.4. Stability

When a sensor is used for a period of time, its ability to remain unchanged is called stability. The factors that affect the long-term stability of the sensor, except the structure of the sensor itself, are mainly the use of the sensor environment. Therefore, in order to make the sensor with good stability, the sensor must have a strong adaptability to the environment. Before choosing the sensor, we should investigate the environment and choose suitable sensors according to the specific environment, or take appropriate measures to reduce the environmental impact. The stability of the sensor has a quantitative index. After the use period, it should be re calibrated before use to determine whether the sensor's performance changes. For some occasions that require sensors to be used for a long time and can not be easily replaced or calibrated, the stability of the selected sensors is more stringent, and it is able to stand the test for a long time.


9.5. Accuracy

Precision is an important performance index of the sensor. It is an important link to the measurement precision of the whole measurement system. The precision of the sensor is high, its price is more expensive, therefore, the precision of the sensor as long as meet the measurement accuracy requirements can be, does not need to be so high. It can meet many sensors with measurement sensor selection in Atlas air compressor accessories is relatively cheap and simple. If the purpose of the measurement is qualitative analysis, the sensor with high repeatability and accuracy can not be selected. The absolute value is not suitable. If we want to get the accurate measurement value for quantitative analysis, we need to select the sensor with accuracy level to meet the requirement. It is necessary to design and manufacture sensors on some special occasions when the suitable sensors can not be selected. The performance of the self-made sensor should meet the requirements of use.


X.Common terms

Sensor/Transducer

A device or device that can feel the measured and converted into an available output signal in accordance with a certain rule. It is usually composed of sensitive elements and conversion elements. A sensitive element is a part of a sensor that can be measured directly (or in response). The conversion element refers to the sensing (or response) of a sensor that can be felt (or response) to be converted into an electrical signal part that is transmitted and / or measured. When the output is a specified standard signal, it is called a transmitter.

Measuring Range

The range of the measured values within the allowable error limit.

Range

The algebraic difference between the upper limit of the measurement range and the lower limit value.

Accuracy

The degree of consistency between the measured results and the true value.

Repeatability

In all the following conditions, the degree of conformity between the results of the repeated measurements of the same measured amount:

l The same measurement method

The same observer

Same measuring instrument

The same place

Same use condition

Repetition in a short period

Resolution

The smallest measure of change that the sensor may have detected in the range of measured measurements.

Threshold

The minimum amount of change measured to produce a measurable change in the output end of the sensor.

Zero

The state that makes the absolute value of the output minimum, such as the state of equilibrium.

Excitation

The external energy (voltage or current) applied to the normal work of a sensor.

Maximum Incentive

The maximum value of the excitation voltage or current that can be applied to the sensor in the city.

Input Impedance

The impedance measured at the input end of the sensor when the output is short circuited.

Output

The amount of electricity generated by the sensor is measured as a function of the external function.

Output Impedance

The impedance measured at the output end of the sensor when the input is short circuited.

Zero Point Output

In the indoor condition, the added is measured as the output of the zero time sensor.

Lagging

The maximum difference in output when the measured value is increased and reduced in a specified range.

Later

The time delay of the output signal change relative to the change of the input signal.

Drift

In a certain time interval, the output of the sensor has an unwanted change that is not related to the measurement.

Zero Drift

Change at the specified time interval and the zero point output under the indoor conditions.

Sensitivity

The ratio of the increment of the output of the sensor to the increment of the corresponding input.

Sensitivity Drift

A change in the slope of a calibration curve caused by a change of sensitivity.

Thermal Sensitivity Drift

A sensitivity drift caused by a change of sensitivity.

Heat Zero Drift

A zero drift caused by a change in the surrounding temperature.

Linearity

The degree of alignment of a calibrated curve to a specified line.

Nonlinearity

The degree of deviation between a calibrated curve and a specified line.

Long-term Stability

The sensor can still maintain the ability to not exceed the allowable error within the specified time.

Natural Frequency

In the absence of resistance, the transducer is free (without external force) oscillating frequency.

Response

The characteristic of a measured change in output.

Compensation Temperature Range

The range of temperature compensated by the sensor to keep the range and the zero balance within the specified limit.

Creep

When the measured machine is kept constant, the output changes within the specified time.

Insulation Resistance

If there is no other regulation, the resistance value measured between the insulation part of the sensor is measured when the specified DC voltage is applied at room temperature.


XI.Environmental influence

The effects of the environment on the sensor are mainly in the following aspects:

a. The high temperature environment causes the melting of the coating material, the opening of the solder joint and the change of the stress in the elastic body. High temperature sensors are often used for sensors working in a high temperature environment; in addition, there must be heat insulation, water cooling or air cooling devices.

b. The effect of dust and humidity on the short circuit caused by the sensor. In this environment, a high tightness sensor should be selected. Different sensors are sealed in different ways, and their airtight differences are very different.

c. The common seals are sealant filling or coating; rubber cushion mechanical fastening seal; welding (argon arc welding, plasma beam welding) and vacuum filling nitrogen seal.

d. From the sealing effect, as the best welding sealing, filling coating sealant for the worst. For the indoor clean and dry environment, the sensor can be glued and sealed. For some sensors that are working in a humid and dusty environment, we should choose the diaphragm heating seal or diaphragm welding seal, vacuum pumping nitrogen filling sensor.

e. In a highly corrosive environment, such as humidity and acidity, the sensor will cause damage to elastomers or short circuit. Therefore, we should choose the outer surface of the sensor that has been sprayed or covered with stainless steel, and has good corrosion resistance and good airtight property.

f. The influence of electromagnetic field on the output disturbance signal of the sensor. In this case, the shielding of the sensor should be checked strictly to see if it has good electromagnetic resistance.

h. Flammable and explosive not only cause thorough damage to the sensor, but also pose a great threat to other equipment and personal safety. Therefore, the sensor work in flammable and explosive environment put forward higher requirements on the explosion-proof performance: in flammable and explosive environment must use explosion-proof sealing cover sensor, the sensor should not only consider the tightness, but also consider the explosion intensity, and cable line leading out end of waterproof and anti explosion etc..


XII.The Selection and Range

The choice of the number of sensors is based on the purpose of the electronic weighing apparatus and the number of points needed to support the scale body. The number of supporting points should be determined according to the principle that the center of gravity of the balance body coincides with the actual center of gravity. Generally speaking, the scale body has several support points to select several sensors, but for some special scale bodies, such as electronic hook scale, only one sensor can be used. Some mechatronic scales should be selected according to the actual situation.

The selection of sensor range can be determined based on the maximum weighing value of the scale, the number of sensors, the weight of the scale body, the possible maximum partial load and the dynamic load. In general, the closer the range of the sensor is to the load assigned to each sensor, the higher the accuracy of its weighing. But in fact, with the sensor payload in addition to known complexes in vitro, there are scale body weight, tare, partial load and vibration and impact load, therefore the selection of sensor range, must consider many factors, to ensure the safety and service life of the sensor.

The calculation formula of the sensor range is determined after taking full account of the factors affecting the scale body and through a large number of experiments. The formula is as follows:

C=K-0K-1K-2K-3 (Wmax+W) /N

C - the rated range of a single sensor

W - weighing body weight

Wmax - the maximum value of the net weight of an object

The number of support points used in the N - scale body

K-0 - Insurance coefficient, the general value is between 1.2 and 1.3

l K-1 - impact coefficient

Center of gravity deviation coefficient of K-2 - scale body

K-3 - wind pressure coefficient

According to the experience, the general should make the sensor work in the 30% to 70% range, but for some there is a big impact in the process of using the instrument, such as dynamic weighing, dynamic weighing, steel scale, in the selection of the sensor, to expand its range, the sensor technology in the range of 20%. 30%, the weighing sensor reserves increases, to ensure the safety and service life of the sensor.

The scope of application of various types of sensors should be considered:

The accuracy level of the sensor includes non linear, creep, creep recovery, hysteresis, repeatability, sensitivity and other technical indicators. When selecting sensors, do not simply pursue a high grade sensor, but not only to satisfy the accuracy requirements of the electronic scale, but also to consider its cost.

The selection of the sensor level must meet the following two conditions:

a. Meet the requirement of instrument input. The weighing display instrument displays the weighing result after the output signal of the sensor is amplified, A/D conversion and so on. Therefore, the output signal of the sensor must be greater than or equal to the size of the input signal required by the instrument. The output sensitivity of the sensor will match the matching formula of the sensor and the instrument, and the calculated result must be greater than or equal to the input sensitivity of the instrument.

b. Meet the requirements of the accuracy of the entire electronic scale. An electronic scale is mainly composed of the scale body, the sensor, the instrument is composed of three parts, the accuracy of sensor selection, the sensor accuracy is slightly higher than the theoretical value, because the theory tends to the restrictions of objective conditions, such as scale body strength is poor, the instrument performance is not very good, scale the bad working environment and other factors directly affect the accuracy requirements of scale, so to improve all aspects of requirements, but also consider the economic benefits, ensure to achieve the purpose of.


XIII.National Stadards

Current national standards related to sensors

Graphical symbols for GB/T 14479-1993 sensor maps

Test method for performance of GB/T 15478-1995 pressure sensor

General specification for GB/T 15768-1995 capacitive humidity sensor and humidity sensor

GB/T 15865-1995 camera (PAL/SECAM/NTSC) measurement method first part: non broadcast single sensor camera

Calibration method for GB/T 13823.17-1996 vibration and shock sensors

Calculation method of main static performance index of GB/T 18459-2001 sensor

GB/T 18806-2002 resistance strain pressure sensor general specification

GB/T 18858.2-2002 low voltage switchgear and control device controller - device interface (CDI) second part: actuator sensor interface (AS-i)

GB/T 18901.1-2002 optical fiber sensor first part: General specification

GB/T 19801-2005 nondestructive testing for acoustic emission detection of acoustic emission sensors for two level calibration

General term for GB/T 7665-2005 sensor

GB/T 7666-2005 sensor naming and code name

GB/T 11349.1-2006 vibration and impact mechanical admittance test determine first parts: basic definition and sensor

GB/T 20521-2006 semiconductor devices Part 14-1: Semiconductor sensors - General principles and classification

GB/T 14048.15-2006 low voltage switchgear and control equipment. Part 5-6: control circuit, electrical appliance and switch element -- DC interface of proximity sensor and switch amplifier (NAMUR).

GB/T 20522-2006 semiconductor device part 14-3: semiconductor sensor pressure sensor

GB/T 20485.11-2006 calibration method for vibration and impact sensors: eleventh part: absolute calibration of laser interference method

GB/T 20339-2006 technical specification for sensor connections fixed to tractors for agricultural tractors and machines

GB/T 20485.21-2007 calibration method for vibration and shock sensors: twenty-first part: calibration of vibration comparison method

GB/T 20485.13-2007 calibration method for vibration and shock sensors: thirteenth part: absolute calibration of laser interference method

GB/T 13606-2007 geotechnical test instrument general technical conditions for vibrating string sensor of geotechnical engineering instruments

Determination of water vapor transmittance of GB/T 21529-2008 plastic film and thin film by electrolysis sensor

GB/T 20485.1-2008 calibration method for vibration and shock sensors: the first part: basic concept

GB/T 20485.12-2008 calibration method for vibration and shock sensors: twelfth part: absolute calibration of reciprocity method of vibration

GB/T 20485.22-2008 calibration method for vibration and impact sensors: twenty-second: impact comparison calibration

GB/T 7551-2008 weighing sensor

GB 4793.2-2008, safety requirements for electrical equipment for measurement, control and laboratory use. Second part: special requirements for hand held and hand operated current sensors for electrical measurement and test.

GB/T 13823.20-2008 calibration method for vibration and impact sensor calibration method for measuring the resonance of accelerometer

Calibration of GB/T 13823.19-2008 vibration and shock sensors calibration by earth gravity method

First parts of Distributed installation in GB/T 25110.1-2010 industrial automation system and integrated industrial applications: sensors and actuators

GB/T 20485.15-2010 calibration method for vibration and shock sensors: fifteenth part: absolute calibration of angular vibration of laser interferometry

GB/T 26807-2011 piezoresistive dynamic pressure sensor

GB/T 20485.31-2011 calibration method for vibration and impact sensors: thirty-first part: Test of lateral vibration sensitivity

Calibration method for GB/T 13823.4-1992 vibration and shock sensors

Calibration method of GB/T 13823.5-1992 vibration and impact sensor installation moment sensitivity test

Calibration method of GB/T 13823.6-1992 vibration and shock sensor base strain sensitivity test

GB/T 13823.8-1994 calibration method for vibration and impact sensors lateral vibration sensitivity test

Calibration method for GB/T 13823.9-1994 vibration and impact sensors lateral impact sensitivity test

The calibration method of GB/T 13823.12-1995 vibration and impact sensors for the resonance frequency test of undamped accelerometers mounted on steel blocks

Calibration method of GB/T 13823.14-1995 vibration and shock sensor by Centrifuge method

Calibration method for GB/T 13823.15-1995 vibration and impact sensors transient temperature sensitivity test

Calibration method for GB/T 13823.16-1995 vibration and shock sensors

GB/T 13866-1992 vibration and impact measurement description of the characteristics of inertial sensors


Analysis

XIV.Technical Characteristics

China's sensor industry is in the critical stage of development from traditional to new sensors. It reflects the general trend of new sensors to miniaturization, multi-function, digitalization, intellectualization, systematization and networking. After many years of development of sensor technology, the development of its technology can be divided into three generations.

The first generation is a structural sensor, which uses the change of structural parameters to feel and transform the signal.

The second generation is a solid sensor developed in 70s. The sensor is made up of semiconductor, dielectric, magnetic materials and other solid elements. It is made of some characteristics of materials. For example, using thermoelectric effect, Holzer effect and photosensitive effect, the thermocouple sensor, Holzer sensor and photosensitive sensor are made respectively.

The third generation of sensors is an intelligent sensor that has just been developed. It is the combination of microcomputer technology and detection technology, which enables sensors to have certain AI.


14.1 Sensor Technology and Industry Characteristics

The characteristics of sensor technology and its industry can be summed up as follows: the base and application are attached; technology and investment are two dense; products and industries are two dispersed.

14.2. The Basis and Application

The basic attachment means that the development of sensor technology depends on the four cornerstones of sensitive mechanism, sensitive material, process equipment and measuring technology. Sensitive mechanisms vary widely, sensitive materials are varied, process facilities are different, and metering technology is quite different. Without the support of the above four cornerstones, sensor technology is difficult to continue.

Application dependency refers to the fact that sensor technology is basically applied technology. Its market development mostly relies on the application of detection device and automatic control system, which can truly reflect its high added benefit and form a real market. That is, the development of sensor technology should be guided by the market and carry out the demand traction.

14.3 Technology Intensive and Investment Intensive

Technology intensive refers to the diversity, borderline, comprehensiveness and artistry of the technology in the process of development and manufacture of sensors. It is a collection of high - tech products. Talent intensive is also naturally required because of technology intensive.

Investment intensity means that research and development and production of a sensor product require a certain investment intensity, especially in engineering research and scale economy production line, which requires greater investment.

14.4. Industrial Decentralization and Product Dispersion

The product structure and industrial structure of the two dispersion refers to the sensor product variety categories (a total of 10 categories, 42 categories of nearly 6000 varieties), the application of penetration into the various industry sectors, its development not only has the industry development impetus, supporting role and is strongly dependent on the industry. Only according to the market demand, the continuous adjustment of industrial structure and product structure can realize the comprehensive, coordinated and sustained development of the sensor industry. 


Book Recommendation

· Getting Started with Sensors: Measure the World with Electronics, Arduino, and Raspberry Pi

Book introduction:To build electronic projects that can sense the physical world, you need to build circuits based around sensors: electronic components that react to physical phenomena by sending an electrical signal. Even with only basic electronic components, you can build useful and educational sensor projects.But if you incorporate Arduino or Raspberry Pi into your project, you can build much more sophisticated projects that can react in interesting ways and even connect to the Internet. This book starts by teaching you the basic electronic circuits to read and react to a sensor. It then goes on to show how to use Arduino to develop sensor systems, and wraps up by teaching you how to build sensor projects with the Linux-powered Raspberry Pi.

--Kimmo Karvinen  (Author),‎ Tero Karvinen  (Author)

· Make: Sensors: A Hands-On Primer for Monitoring the Real World with Arduino and Raspberry Pi 

Book introductionSensors is the definitive introduction and guide to the sometimes-tricky world of using sensors to monitor the physical world. With dozens of projects and experiments for you to build, this book shows you how to build sensor projects with both Arduino and Raspberry Pi. Use Arduino when you need a low-power, low-complexity brain for your sensor, and choose Raspberry Pi when you need to perform additional processing using the Linux operating system running on that device.You'll learn about touch sensors, light sensors, accelerometers, gyroscopes, magnetic sensors, as well as temperature, humidity, and gas sensors.

--Tero Karvinen  (Author),‎ Kimmo Karvinen (Author),‎ Ville Valtokari  (Author)


Relevant Information About "Most Comprehensive Sicence Popularizing of Sensor (detection device)"

About the article "Most Comprehensive Sicence Popularizing of Sensor (detection device)", If you have better ideas, don't hesitate to  write your thoughts in the following comment area. You also can find more articles about electronic semiconductor through Google search engine, or refer to the following related articles.

· Silicon-Carbide Coating Protects Flow and Liquid Level Sensor Modules

· The Techniques to Improve Capacitive Touch Sensing

·Capacitive Touch Sensing of Sensors

· 2D and 3D Smart Material Pressure Sensors--A New Progress

·HTD Differential Pressure Sensors with 15-bit Resolution from First Sensor

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