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IntroductionIC packaging refers to the material that contains a semiconductor device. The package is a case that surrounds the circuit material to protect it from corrosion or physical damage and allow mounting of the electrical contacts connecting it to the printed circuit board (PCB). Let's take a look at some of the different types of packaging options you can use to enhance your product & customer experience.CatalogIntroductionⅠ How Do You Find the Right IC Packages?Ⅱ What are IC Made Up of?Ⅲ How Many Types of IC Packages Are There?3.1Through-hole Technology (THT)3.2 Surface-mount Technology (SMT)3.3 Through-Hole vs Surface MountⅣ IC Packages Selection SummaryⅠ How Do You Find the Right IC Packages?There was a lot of change in the way electronics components appeared or packaged, from bulky vacuum tubes to lightweight SMD ICs. Because IC packaging indicates the dimension and shape of a chip, to minimize the number of components on board, manufacturers are actively working to reduce the size of ICs, and multiple components are also being increasingly incorporated into LSI, VLSI, and ULSI designs. Almost all components are currently available in two or three different package forms, from which the engineer can pick the one that best fits device application. We will learn about the various IC package forms in this article and where they can be useful.Types of IC | IC Package Types ExplainedⅡ What are IC Made Up of?Before introducing the various forms of IC packages, we can learn about the process of IC manufacturing firstly. ICs consist of monolithic, hybrid, or film circuits, as a matter of fact. The development steps for the IC are as follows:LithographyIt is a technique for defining a pattern in which a photoresist material is added to the wafer surface evenly and then baked to harden. Later, light is projected and selectively extracted via a reticulum containing mask details.EtchingThe undesired materials are separated from the wafer surface.DepositionMaterials are added to the wafer through the process of Physical Vapor deposition and chemical vapor deposition.Chemical Mechanical PolishingA planarization technique by the application to the wafer surface of a chemical slurry with etchant agents.OxidationOxygen (dry oxidation) or HO (wet oxidation) molecules convert silicon layers to silicon dioxide on top of the wafer in the oxidation process.Ion implantationThe most commonly used method for the semiconductor incorporation of dopant impurities. The ionized particles are accelerated and targeted at the semiconductor wafer via an electrical field.DiffusionFor annealing bombardment-induced lattice defects, a diffusion phase following ion implantation is used.IC Design & Manufacturing Process OverviewⅢ How Many Types of IC Packages Are There?A very huge variety of integrated circuits have different packaging requirements. Based on how they are placed on a circuit board, the packages are divided into two types.3.1Through-hole Technology (THT)Through-hole MountingThey are designed to trap the lead pins on one side of the board and smolder on the other side. Compared to other forms, they are larger in scale. These are mainly used in electronic equipment to compensate for the limitations of board space and expense. One example of through-hole mount packages is dual inline packages.DIP and ZIPThrough-hole mount packages come in ceramic and plastic forms to add up to the classification.The most widely used IC packages are Dual Inline Packages (DIP). As in 28-pin ATmega328, the pins are positioned parallel to each other, extending perpendicularly and laid out on a rectangular black plastic housing. The pins are 0.1 inches apart. Additionally, because of the variation in the number of pins in various packages, the box differs in size. They range in number from 4 to 64. These pins are positioned in a way that they can be changed without short-circuiting each other or even smoldering into PCBs at the center of a breadboard.The few common types are Plastic Dual In-Line Package (PDIP) and Molded Dual In-Line Package (MDIP). There are several types of DIP packages. It can further be categorized as:Norm - The most prevalent packaging is this. The pins are spaced apart by 0.1". Skinny - The space between the terminal rows in this box is 7.62mm.Shrink - Identical to the regular ones, but 1.778 mm is the lead pitch. Smaller in size, they use packaging with high pin density.Zig-Zag in Line Packages (ZIP)- Pins are inserted perpendicular to the circuit board in this kind of package. In the box, these pins are aligned perpendicularly and are closer to each other. This style of packaging was short-lived and was primarily used in RAM chips that were dynamic. CER-DIP comprises other types of through-holed packages in which the lead pitch is 2.54 mm and the body is molded with ceramics. Also, glass is the sealing medium used here. The lead pitch of the Pin Grid Array (PGA) is 2.54 mm and the body is made of ceramic. The pins from the body are arranged vertically and can be positioned on a grid. Typically, this one fits a multi-pin kit.3.2 Surface-mount Technology (SMT)Surface Mount DefinitionThe technology of installing or positioning the components directly onto the printed circuit board surface is accompanied by surface mount packaging. While this manufacturing process helps to rapidly do stuff, it also raises the likelihood of defects. This is due to component miniaturization and also because they are placed very close to each other. This, in fact, results in the detection of the deficiency in the entire process becoming extremely significant. Again, ceramic or plastic molding is often used in Surface Mount packaging.Types of SMTThe following are the various types of surface mount packages that use plastic molds:(1) Small Outline L-leaded PackageThis type has leads of the gull-wing type that draw in a L fashion from the body in either direction and can be placed directly on the frame. QFP (Quad Flat L-leaded Packages)-These are SOP-like. The only difference, however, is that the leads are drawn out in 4 directions instead of 2 and are directly placed on the frame. They even come with a heat sink and a heat spreader built in.(2) Ball Grid Array (BGA)A ball grid array (BGA) is a type of surface-mount packaging (a chip carrier) used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. As for BGA soldering, the solder balls on the package have a very carefully controlled amount of solder, and when heated in the soldering process, the solder melts. Surface tension causes the molten solder to hold the package in the correct alignment with the circuit board, while the solder cools and solidifies.3.3 Through-Hole vs Surface MountThe two kinds of packaging have their individual advantages and disadvantages - primarily through-hole mounting and surface mounting. Here's a comparison with different variables between through-hole and surface mount devices that adjust the need for the form of IC packages.1. Size - In contrast with through-hole packages, surface mount packages are smaller.2. Component density - Component density as well as attachment density are comparatively higher for surface mounting packages.3. Assembly- In contrast to through-hole packages that can not afford even the smallest of errors when making holes, minor errors are immediately corrected by the molten solders that bring components close together due to stress in surface mounting packages. This is because, once made, the alignment can not be changed.4. Electromagnetic compatibility - The ability of various electronic devices and components, even in the presence of other devices that produce electromagnetic waves, to operate correctly. Packages for surface mounting have better EMC performance.5. Cost - Because of automated processes, the manufacturing cost is often lower than that of through-hole packages.Surface mount packages do not, however, operate together with a simple plugin on the breadboard. They need a pin-led carrier to be installed. Or worse, they can need special PCBs customized separately for various prototypes.Ⅳ IC Packages Selection SummaryICs are put into protective packages to allow easy handling and assembly onto PCBs and to protect the devices from damage. Therefore, a suitable package type is important for ic applications. First of all, let us emphasize enough how important it is to have good packaging. To allow smooth handling and installation on the printed circuit boards, integrated circuits are placed into packages. To prevent any kind of harm and corrosion, it is extremely imperative to bring ICs into packages. The packages also assist in the dissipation of the heat generated. This is, however, the final part of the entire fabrication process. Consider certain important factors, such as assembly capacity, strength, cost, and connectivity, before deciding on the type of packaging that best suits you.With the ever-present innovations, several kinds of semiconductor integrated circuits packages have appeared. The motive is to choose for yourself the correct type of IC package that is affordable and yet does not compromise with efficiency. Most important thing, chips with the same electronic parameters may have different package types. Frequently Asked Questions about Types of IC Packages1. What is IC package design?IC packaging refers to the material that contains a semiconductor device. The package is a case that surrounds the circuit material to protect it from corrosion or physical damage and allow mounting of the electrical contacts connecting it to the printed circuit board (PCB). 2. What are the different types of IC packages?DIP (Double In-line Package)SOP/SOIC/SO (Small Outline Package)QFP (Quad Flat Package)QFN/LCC (Quad Flat Non-leaded Package)BGA (Ball Grid Array Package)CSP (Chip Scale Package) 3. What is the most common type of digital IC package?DIP (Dual in-line packages)DIP, short for dual in-line package, is the most common through-hole IC package you'll encounter. These little chips have two parallel rows of pins extending perpendicularly out of a rectangular, black, plastic housing. 4. How many types of IC are there?TwoThere are two main types of integrated circuits: digital ICs or analog ICs. 5. What are the types of packaging materials?Different Types of Packaging Materials1) Plastic. The most common packaging methods in industries is plastic.2) Aluminum. Aluminum is widely used for products such as sodas, beer, canned goods and animal foods.3) Cardboard. Most products that are packaged in cardboard boxes are first wrapped in another type of packaging such as bubble wrap or foam.4) Glass5) Foam

IntroductionIn-memory computing (IMC), a technique of future computing, stores data in RAM to run calculations entirely in computer memory. With the rise of the big data era, faster data processing capabilities are required. Computer memory and storage space are also growing exponentially to adapt to large-capacity data collection and complex data analysis, which promotes the development of AI (artificial intelligence), and then derives emerging stuff, that is, in-memory computing.In-memory Computing (IMC) ExplainedCatalogIntroductionⅠ Memory Wall: Processor /Memory Performance GapⅡ Developing RequirementⅢ What Is In-memory Computing?3.1 In-memory Computing Definition3.2 Four Realization MethodsⅣ Driving Force of In-memory Computing and Market Prospects4.1 In-memory Computing for AI4.2 In-memory Computing Product Outlook4.3 In-memory Computing Market and ProspectⅤ ConclusionⅠ Memory Wall: Processor / Memory Performance GapThe von Neumann architecture has occupied the dominant position in computer system when the computer invented. This kind of calculation method is to store the data in the main memory first, and then fetch the instructions from the main memory to execute them in order when running. We all know that if the connecting speed of the memory cannot keep up with the performance of the CPU, the computing will be limited. This is a memory wall. At the same time, in terms of efficiency, the von Neumann architecture also has obvious shortcomings. It consumes more energy to read and write data than to calculate once time.Figure 1. Von Neumann Architecture DiagramThe performance of computer processors has developed rapidly based on Moore's Law, and has been directly improved with the invention of transistors. The main memory of the computer uses the DRAM. It is a high-density storage solution based on capacitor charging and discharging. Its performance (speed) depends on two aspects, namely the reading/writing speed of the capacitor charging and discharging in the memory and the interface bandwidth between the devices. The read/write speed of capacitor charging and discharging has increased with Moore’s Law, but the speed is not as fast as the processor. In addition, the interface between DRAM and the processor is a mixed-signal circuit, and its bandwidth increasing speed is mainly restricted by the signal integrity of the traces on the PCB. This has also caused the performance improvement of DRAM to be much slower than that of the processor. At present, the performance of DRAM has become an huge bottleneck of overall computer performance, the so-called "memory wall".  It blocks the computing performance improvement.Figure 2. Moore's Law Effect Ⅱ Developing RequirementIn the current AI technology, with the increasing amount of data and calculations, the original von Neumann architecture is facing more and more challenges. Rely on expanding CPU, the hardware architecture can’t have a large amount of calculation. Also the larger storage capacity is heavily rely on the past architecture, it is also very unsuitable for AI. When the memory capacity is large to a certain extent, it can only show that certain technologies need innovation. In order to solve the "memory wall" problem, future computers are not based on computing memory, but the in-memory computing, thereby reducing the cost of data access in the calculation process.Figure 3. Conventional Computing vs In-memory Computing Ⅲ What Is In-memory Computing?3.1 In-memory Computing DefinitionIn-memory computing (or in-memory computation) is a technique based on RAM data storage and indexing, which proposed by the MIT research group, and its main purpose is to accelerate the convolution calculation. We know that convolution calculations can be expanded into weighted accumulation calculations. From another perspective, it is actually a weighted average of multiple numbers. Therefore, the circuit realizes the weighted average of the charge domain. The weight (1-bit) is stored in SRAM, and the input data (7-bit digital signal) becomes an analog signal through the DAC. According to the corresponding weight in the SRAM, the output is multiplied by 1 or -1 in the analog domain, which averaged in the analog domain, and finally read out by the ADC as a digital signal. Specifically, since the weight of the multiplication is 1-bit (1 or -1), it can be controlled by using a switch and a differential line simply. If the weight is 1, the capacitor on the side of the differential line is charged to the required output value. Otherwise, let the other side of the differential line be charged to this value. As for average, connect several differential lines together in the charge domain.Of course, there is more than one circuit for in-memory calculation, and the calculation accuracy is not limited to 1-bit. However, we can see the above examples that the core idea of in-memory calculations is generally to convert calculations into weighted calculations. Store the weights in the memory unit, then modifications on the core circuit of the memory (such as the readout circuit) are made. So that the process of reading is like a process in which the input data and weights are multiplied in the analog domain, that is, convolution. Because convolution is a core part of AI and other calculations, in-memory computing can be widely used in such applications. In-memory computing uses analog circuits for calculations, which is the difference compared with traditional digital logic calculations.In more traditional architectures, there are some multiply-accumulate circuits (MAC) for tensor math, especially the matrix multiplication. These architectures attempt to arrange the MAC in a way that moves weights and activations to the appropriate location. Activations are calculated from the previous neural network layer. Multiplication usually involves activations and weights, both must be moved to the place where multiplies them. In-memory computing makes use of it. Therefore, if the weights are stored in memory, the memory can access through activations to obtain multiplication and accumulation. The only difference from the actual memory is that the in-memory computing concatenates all word lines at once, instead of decoding the input to get one word line only.Figure 4. In-memory Computing Diagram3.2 Four Realization MethodsThe attempt is to enter the analog domain and treat the storage unit as an analog unit instead of a digital unit to reduce consumption. We have already got a way to use simulation on the front end of the inference engine. That is in-memory computing. Therefore, we take digital data, using a DAC to convert it to an analog value, and then driving a memory with these analog content to obtain an analog bit-line output, finally using an ADC to convert the result back to a digital format. However, the in-memory computing is still in the exploratory stage, and there are many specific implementation methods to study, currently there are three types: RRAM, Flash, SRAM, and DRAM.Based on RRAMRRAM is the most common method of doing this, because it is easy to use by applying Ohm's law to a series of resistors, but it still has the problem of relying on RRAM. The relationship between programming and resistance is non-linear, which requires more work to be done to make viable calculation circuits in RRAM memory for market. So it is just an idea, and the specific plan is still under study. Based on FlashNOR Flash memory has a more traditional word-line/bit-line structure. It is both resistive and capacitive. Generally, the memory cell is a transistor that is turned on or off. However, if it is partially conductive, it can be used as a resistor. The resistance depends on the amount of charge on the floating gate of the memory cell (capacitor). When running all the time, the cell will conduct to its maximum capacity. During this process, it does not conduct at all, however, it can be partially programmed. There is a problem is that you cannot precisely control the number of electrons. Moreover, the response to any number will vary with the process and temperature and other variables.Two companies are studying this method. Microchip owns their memBrain array, thanks to their acquisition of SST, and Mythic is a start-up company dedicated to an inference engine that uses in-memory computing with flash memory. Both companies said that they are using extensive calibration techniques to deal with this change.Another issue, flash cells will lose electrons over time. Electrons will flow around, which brings up an interesting topic: on this type of memory array, data retention and durability will be like.From the application point of view, it depends on whether it is to be used in cloud computing or edge inference engine. At the edge, it may perform certain fixed reasoning functions throughout the life cycle of the device. Therefore, if there are enough arrays, then you will load the weights for the first time and don't need to program it anymore (unless you do a update), because the flash memory is non-volatile. Although you still need to move activations, there is no need to move the weights, which will be stored permanently in the array. This would indicate that data durability (number of times the device can be programmed before cumulative damage accelerates electron leakages to an unacceptable level) does not matter, it only need to program once.In contrast, in cloud applications, the device is likely to be shared as a general-purpose computing resource, so this requires reprogramming for each new application. This means that battery life becomes more important in the cloud. Mythic claims to have a 10K write cycle, and has observed that even if it is reprogrammed every day, it will last for more than 10 years.If set an analog value for it and use an analog value in the cell, then in theory, each electron is important. However, if there is enough electron migration, you need to refresh the storage unit, or compensate for electrons change in some way. Because the same analog input today will produce different results than a year ago. The calibration circuit can also deal with some aging problems. However, for data retention, Mythic said they do perform regular updates of the weight values stored in flash memory. This will make persistence the main wear-out mechanism rather than data retention. Microchip stated that its data retention time is TBD, but it is likely to reprogram the device quarterly or annually to restore the unit.So they need a large number of high-quality ADCs and DACs to keep the signal-to-noise ratio (SNR) within a scope of accurate reasoning, which is the focus of designing work. Mythic claims that they provide a novel ADC, so that Microchip can share it to reduce the number required. Although ADC does consume energy, it also greatly reduces overall system consumption. Based on SRAMThis idea came from a lecture at Hot Chips at Princeton University. By definition, SRAM is a bistable unit. Therefore, it cannot be in an intermediate state, how should this be handled? And the DACs and ADCs that need to be corrected more over than the array in terms of area and power consumption.The point of this problem boils down to the question of how to simulate. They explained that this method uses more than one-bit line for calculation. Since the unit is still a digital value, it takes several bit lines to perform a calculation. The bit line can be split, and different groups perform different multiplications. The following figure illustrates it.Figure 5. Bit LineWith 8 inputs at a time, so the input vector is sliced and several consecutive multiplications are carried out to obtain the final results. The bit line charge is deposited on the capacitor. When ready to read, the charge is read out and sent to the ADC for conversion back to the digital domain. Their basic unit structure is as follows:Figure 6. Bit CellThese capacitors may affect chip size issues, but they said that the metal above the cell can be used. Of course, one cell is now 80% larger than the standard 6T SRAM cell (even without capacitors), but they say that their overall circuit is still much smaller than a required circuit based on standard digital implementation. In addition, since their basic array operations are still in digital form, they are less sensitive to noise and changes, which means their ADCs can be simpler and consume less power.Figure 7. Chip SizeBased on DRAMThis idea refers to not using a lot of power to obtain DRAM content, and in some way incorporate calculations into the CPU or other computing structures and directly run it on the DRAM die, which is what UPMEM does. A simple processor is built on the DRAM die, also the architecture will not compete with Xeon chips, they call this set "processing in memory" or PIM.Figure 8. PIM ChipInstead of bringing data to calculations, they bring calculations to data. The runtime is performed by the CPU in DRAM chip. That is, there is no need to move the data to any location outside of the DRAM chip, just send the calculating result back to the host system. Also, since ML calculations usually involve a lot of reduction, less data required for calculations. Although this does require some minor changes to the DRAM, they did not change the manufacturing process. Under this case, a standard DRAM module will provide multiple opportunities for distributed computing. At the same time, it becomes complicated to use this function to write a program.They said that a server using PIM offload will consume twice as much power than a standard server connected to a DRAM module without PIM. However, with a throughput of 20 times, it still provides them with a 10 times energy efficiency advantage. In addition, this method can help defend against side-channel security attacks. Thus a group of computing threads originally contained in one or more CPUs flows to DRAM. Therefore, it is necessary to check all DRAMs and figure out where thread is in some way, but this will be a difficult task. Ⅳ Driving Force of In-memory Computing and Market Prospects4.1 In-memory Computing for AIPeople have recognized the problem of "memory wall" for a long time, but why is in-memory computing only raised in the past two years? So we have to analyze the boost behind its rise.The first motivation is the rise of AI based on neural networks, especially the hope that AI can be popularized in mobile and embedded devices. So that in-memory computing with a high energy efficiency ratio has attracted attention. In addition, neural networks have a high tolerance for errors in calculation accuracy. Therefore, errors introduced in simulation calculations of in-memory computing can often be accepted. That is to say in-memory computing and AI are good partners for each other.The second motivation is the new memory. For in-memory computing, the memory characteristics often determine the efficiency of in-memory computing. Therefore, new memories improvement will often drive the development of in-memory computing. For example, the recently popular ReRAM uses resistance modulation to store data, so the readout of each bit uses a current signal instead of a traditional charge signal. In this way, it is a very natural operation for current to accumulate (combining several currents directly to achieve the sum of currents, even without additional circuits). That is to say, ReRAM is very suitable for in-memory calculations. From the perspective of memory promotion, new memories are also willing to catch up with the AT trend. Therefore, new memory manufacturers are also happy to see in-memory computing based on their own memories to accelerate AI development, which will broaden the memory market. 4.2 In-memory Computing Product OutlookChip products for in-memory computing are expected to come in two forms. The first form is sold as a memory IP with computing functions. Such memory IP may be traditional SRAM, or new memory such as eFlash, ReRAM, MRAM, and PCM.The second form is to directly build AI acceleration chips based on in-memory calculations. For example, Mythic plans to make PCIe accelerator cards based on flash memory, that is, access data with the main CPU through the PCIe interface. The weight data is stored on the Mythic memory chip, so that when the data is sent to the Mythic IPU, the calculation can be directly read out. In this way, the action of reading the weights data is eliminated.Figure 9. Mythic is a Pcie Accelerator 4.3 In-memory Computing Market and ProspectWhat impact will in-memory computing have on the AI chip market? First of all, we see that in-memory computing uses analog calculations, so its accuracy will be affected by the low signal-to-noise ratio. Usually the upper limit of accuracy is about 8-bit, and it can only do fixed-point calculations not the floating-point calculations. So in-memory computing is not suitable for the AI training market that requires high calculation accuracy. In other words, the main battlefield of in-memory computing is the AI inference market. For example, it is more suitable for embedded artificial intelligence, which has high requirements for energy efficiency not the accuracy. In fact, in-memory computing is actually most suitable for occasions where large memory is needed. For instance, flash is inherently required in IoT and other scenarios, so if you can add the in-memory computing to flash, it is quite suitable. However, introducing in-memory computing in a large storage memory may not appropriate. Based on this analysis, we believe that in-memory computing may become an important part of embedded AI (such as smart IoT) in the future. Ⅴ ConclusionWith the rise of AI and new memories, in-memory computing has also become a new hot spot. Based on the unique characteristics of the memory, it combines with analog calculations in memory, thereby greatly reducing the memory read and write operations in AI. Although the accuracy of calculation in the memory is limited by analog calculation, it is also suitable for embedded AI applications that pursue energy efficiency most and can accept a certain loss of accuracy. Frequently Asked Questions about In-Memory Computing Technology1. Why do we need in memory computing?In-Memory Computing provides super-fast performance (thousands of times faster) and scale of never-ending quantities of data, and simplifies access to increasing numbers of data sources. 2. What does in memory mean?An in-memory database is a type of purpose-built database that relies primarily on memory for data storage, in contrast to databases that store data on disk or SSDs. ... Because all data is stored and managed exclusively in main memory, it is at risk of being lost upon a process or server failure. 3. How does in memory computing work?In-memory computing means using a type of middleware software that allows one to store data in RAM, across a cluster of computers, and process it in parallel. Consider operational datasets typically stored in a centralized database which you can now store in “connected” RAM across multiple computers. 4. What is in memory computing in SAP HANA?An In-Memory database means all the data from source system is stored in a RAM memory. In a conventional Database system, all data is stored in hard disk. It provides faster access of data to multicore CPUs for information processing and analysis. 5. How is data stored in memory?Normally memory is described as a storage facility where data can be stored and retrieved by the use of an address. This is accurate but incomplete. A computer memory is a mechanism whereby if you supply it with an address it delivers up for you the data that you previously stored using that address. 6. What is in memory data processing?In-memory processing is the practice of taking action on data entirely in computer memory (e.g., in RAM). ... Since the storage appears as one big, single allocation of RAM, large data sets can be processed all at once, versus processing data sets that only fit into the RAM of a single computer. 7. What is in memory database processing and what advantages does it provide?The major advantage of systems using in-memory databases vs traditional database systems is: its performance speed. ... Source data is loaded into the system memory in a compressed and format. Therefore, in-memory processing reduces disk seek time for accessing data and streamlining the work involved in processing queries. 8. What is big data computing?Big data computing is an emerging data science paradigm of multi dimensional information mining for scientific discovery and business analytics over large scale infrastructure. ... Big data is characterized by 5V's such as volume, velocity, variety, veracity, and value.

I IntroductionLaser sensor is a kind of sensor which uses laser technology to measure. It is generally composed of laser, optical parts and photoelectric devices. It can convert the measured physical parameters (such as length, flow, speed, etc.) into optical signals, and then use photoelectric converter to convert the optical signals into electrical signals. Through the filtering, amplification and rectification of corresponding circuits, the output signals can be obtained, so as to calculate the measured quantity. Laser technology has the characteristics of strong direction, high brightness and good monochromaticity. It is widely used in industrial and agricultural production, national defense and military, medical and health, scientific research and other aspects, such as distance measurement, precision detection, positioning, etc., as well as length benchmark and optical frequency benchmark.Laser Distance Sensor OverviewCatalogI IntroductionII What is Laser? 2.1 The Concept of Laser 2.2 Important Characteristics of Laser 2.3 Types of Laser 2.4 What can Laser Sensor Detect?III Laser Displacement Sensor 3.1 What is Laser Displacement Sensor 3.2 How Does Laser Displacement Sensor Work? 3.3 Application of Laser Displacement Sensor 3.4 What are the Parameters to Know When Choosing a Laser Displacement Sensor?IV Laser Distance Sensor 4.1 Classification of Laser Distance Sensors  4.2 Measuring Principle of Different Laser Distance Sensors 4.3 Application of Laser Distance SensorV Laser Sensor Application CaseVI FAQII What is Laser?2.1 The Concept of LaserLaser light is different from ordinary light. (See more about light and photoelectric effect in the article introducing light sensor and photoresistor)We need to use laser to produce laser light. In the normal state, most of the atoms in the laser are in stable low energy level E1. Under the action of appropriate frequency of external light, the atoms in low energy level absorb photon energy to excite and transition to high energy level E2. The photon energy E = e2-e1 = h V, where h is the Planck constant and V is the photon frequency.  On the contrary, when the frequency of light is V, the atom in level E2 will jump to the low energy level to release energy and emit light, which is called stimulated radiation. First of all, the laser makes the atoms of the working materials abnormally in the high-energy level (i.e. inversion distribution of the particle number ), which can make the stimulated radiation process dominant, so that the induced light with the frequency of V can be enhanced, and the large stimulated radiation light can be produced through the avalanche amplification of the parallel reflector, which is called laser light for short.Figure1. Laser2.2 Important Characteristics of Laser（1）High directivity, small divergence angle of light speed, the laser beam extends only a few centimeters from a few kilometers away.（2）High monochromaticity, the frequency width of laser light is more than 10 times smaller than that of ordinary light.（3）High brightness, laser beam convergence can produce temperatures up to several million degrees.2.3 Types of LaserLaser can be divided into four types according to working substance:（1）Solid state laserIts working substance is solid. Ruby laser, neodymium doped yttrium aluminum garnet laser (i.e. YAG laser) and neodymium glass laser are commonly used. Their structures are basically the same, characterized by small and solid, high power. At present, neodymium glass laser is the device with the highest pulse output power, which has reached tens of megawatts.（2）Gas laserIts working substance is gas. Now there are various kinds of gas atoms, ions, metal vapor, gas molecular lasers. Commonly used are carbon dioxide laser, helium neon laser and carbon monoxide laser, whose shape is like a common discharge tube, characterized by stable output, good monochromaticity, long life, but small power, low conversion efficiency.（3）Liquid laserIt can be divided into chelate laser, inorganic liquid laser and organic dye laser, the most important of which is organic dye laser. Its main feature is that the wavelength is continuously adjustable.（4）Semiconductor laserIt is a younger laser, and the more mature one is GaAs laser. It is characterized by high efficiency, small size, light weight and simple structure, and is suitable for carrying on airplanes, warships, tanks and infantry. It can be made into range finder and sighting device. However, the output power is small, the directivity is poor, and it is greatly affected by the ambient temperature.2.4 What can Laser Sensor Detect? (1) Laser measurement of lengthPrecise measurement of length is one of the key technologies in precise machinery manufacturing industry and optical processing industry. Modern length measurement is mostly based on the interference phenomenon of light wave, and its accuracy mainly depends on the monochromaticity of light. Laser is the most ideal light source. It is 100 thousand times purer than the best monochromatic light source (krypton-86 lamp). Therefore, the laser measurement range of length is large and the accuracy is high.  According to the optical principle, the relationship between the maximum measurable length L of monochromatic light and wavelength λ and spectral line width δ is L = λ 2 / δ. The maximum measurable length of krypton-86 lamp is 38.5cm. For a long object, it is necessary to measure in sections to reduce the accuracy. If He-Ne gas laser is used, it can measure tens of kilometers at most. Generally, the length within several meters can be measured with an accuracy of 0.1 μ M.Figure2. Laser Measure(2) Laser measurement of distanceIts principle is the same as that of the radio radar. After the laser is aimed at the target, the round-trip time is measured, and then the round-trip distance is obtained by multiplying the speed of light. Because of the advantages of laser, such as high directivity, high monochromaticity and high power, these are very important for the measurement of long distance, the determination of target orientation, the improvement of signal-to-noise ratio of the receiving system, and the guarantee of measurement accuracy, so the laser rangefinder is paid more and more attention.  The lidar developed on the basis of the laser rangefinder can not only measure the distance, but also the azimuth, velocity and acceleration of the target. It has been successfully used in the ranging and tracking of the artificial satellite. For example, the lidar using ruby laser has a distance measuring range of 500-2000 km with an error of only a few meters. At present, ruby laser, neodymium glass laser, carbon dioxide laser and Gas laser are often used as the light source of laser rangefinder.Figure3. Measuring Distance with Laser Sensor (3) Laser measurement of thickness Based on the principle of triangle ranging, a precise laser ranging sensor is divided at the upper and lower part of the C-frame. The modulated laser emitted by the laser hits the surface of the measured object. By sampling the signal of the linear CCD, the distance between the measured object and the C-frame is synchronously obtained by the linear CCD camera under the control of the control circuit. The thickness of the middle measured object is calculated by the data fed back by the sensor. Because the detection is continuous, the continuous dynamic thickness of the measured object can be obtained.Figure4. Thickness Measuring with Laser SensorThickness measurement by single laser displacement sensorPut the measured body on the measuring platform, measure the distance from the sensor to the platform surface, then measure the distance from the sensor to the measured body surface, and measure the thickness after calculation. It is required that there is no air gap between the measured body and the measuring platform, and the measured body is not cocked. These strict requirements can only be achieved offline.Thickness measurement by double laser displacement sensorA laser displacement sensor is installed above and below the measured body respectively, and the thickness of the measured body is d = C - (a + b). Among them, C is the distance between two sensors, a is the distance between the upper sensor and the measured body, and B is the distance between the lower sensor and the measured body. The advantage of this method for on-line thickness measurement is that it can eliminate the influence of the vibration of the measured body on the measurement results.  But at the same time, there are requirements for sensor installation and performance. The conditions to ensure the accuracy of measurement are that two sensor beams must be coaxial and that two sensor scans must be synchronous. Coaxiality is realized by installation, and synchronization depends on the selection of laser sensor with synchronization end.Figure5. Thickness MeasurementIII Laser Displacement Sensor3.1 What is Laser Displacement SensorThe laser displacement sensor is called the eyes of the robot and machine, and has an irreplaceable role in welding, blank manufacturing, mechanical processing, heat treatment, loading and unloading, assembly and other operations. So, what is a laser displacement sensor? The laser displacement sensor is a sensor that uses laser technology for measurement, and is composed of a laser, a laser detector, and a measurement circuit. As a new type of measuring equipment, the laser displacement sensor can accurately measure the position, displacement and other changes of the measured object, and can also measure precise geometric measurements such as displacement, thickness, vibration, distance, and diameter.3.2 How Does Laser Displacement Sensor Work?The laser displacement sensor can accurately and non-contactly measure the position, displacement and other changes of the measured object, and is mainly used to measure the displacement, thickness, vibration, distance, diameter and other geometric quantities of the object. According to the measurement principle, the principle of laser displacement sensor is divided into laser triangulation method and laser echo analysis method. Laser triangulation method is generally suitable for high-precision and short-distance measurement, while laser echo analysis method is used for long-distance measurement. The following is the introduction to two measurement methods of laser displacement sensor principle.TriangulationFigure6. Laser Displacement SensorThe laser emitter shoots the visible red laser to the object surface through the lens, and the laser reflected by the object passes through the receiver lens, which is accepted by the internal CCD linear camera. According to different distances, the CCD linear camera can "see" this light point at different angles. According to the distance between the laser and the camera known from this angle, the digital signal processor can calculate the distance between the sensor and the measured object. At the same time, the position of the beam in the receiving element is processed by analog and digital circuits, and the corresponding output value is calculated by microprocessor analysis, and the standard data signal is output in proportion in the analog quantity window set by the user. If switching value output is used, it will be conducted in the settings window and cut off outside the window. In addition, an independent detection window can be set for analog quantity and switch quantity output.Echo analysisThe laser displacement sensor can achieve a certain degree of accuracy by using the echo analysis principle to measure the distance. The sensor is composed of processor unit, echo processing unit, laser transmitter and laser receiver. The laser displacement sensor emits one million pulses per second through the laser transmitter to the detector and returns to the receiver. The processor calculates the time required for the laser pulse to meet the detector and return to the receiver, so as to calculate the distance value.  The output value is the average output of thousands of measurement results. It is the so-called pulse time method. The laser echo analysis method is suitable for long-distance detection, but the measurement accuracy is lower than the laser triangulation method, and the longest detection distance can reach 250m.3.3 Application of Laser Displacement Sensor(1) Dimension measurement: position identification of small parts; monitoring of whether there are parts on the conveyor belt; detection of material overlapping and covering; control of manipulator position (tool center position); device state detection; detection of device position (through the small hole); monitoring of liquid level; thickness measurement; vibration analysis; collision test measurement; automobile-related test, etc. (2) Thickness measurement of sheet metal: laser sensor measures the thickness of sheet metal. Thickness change detection can help to detect wrinkles, small holes or overlaps to avoid machine failure. (3) Cylinder measurement: angle, length, eccentricity of inner and outer diameter, conicity, concentricity and surface profile.Figure7. Application of Laser Displacement Sensor(4) Length measurement: place the measured component on the conveyor belt at the designated position, the laser sensor detects the component and simultaneously measures it with the triggered laser scanner, and finally obtains the length of the component. (5) Uniformity check: place several laser sensors in a row in the tilt direction of the workpiece movement to be measured, and directly output the measurement value through one sensor. In addition, the software can be used to calculate the measurement value and read out the result according to the signal or data. (6) Inspection of electronic components: two laser scanners are used to place the tested components between them. Finally, the data is read out by the sensor, so as to detect the accuracy and integrity of the component size. (7) Inspection of filling level in production line: laser sensor is integrated into the production and manufacturing of filling products. When the filling products pass through the sensor, it can detect whether the filling is full. The sensor can accurately identify whether the filling product is qualified and the quantity of the product by using the extended program of laser beam reflecting surface. 3.4 What are the Parameters to Know When Choosing a Laser Displacement Sensor?Some parameters that must be understood when selecting a laser displacement sensor are very important.(1) Resolution: generally refers to the minimum range of the sensor, that is, the maximum recognition rate of the sensor. If the parameter is marked as 1mm, then the resolution is equal to 1mm. (2) Repeatability: We must know that even if the measured object is at rest, the measured value will fluctuate slightly. The error margin of repeated measurement of the measured object at the same position in the static state is the repeat accuracy. For example, if the parameter is marked as 1μm, the repeat accuracy of the sensor is 1μm. (3) Full range (effective range): the rated effective range of the sensor. When selecting a sensor, we must select the sensor that contains the effective range according to the required detection distance. (4) Linear accuracy: the error between the measured value and the actual displacement. Linear accuracy is expressed as a percentage, but since the range is a range and the measurement accuracy is more difficult to reach the apex of the range, most sensors will mark the linear accuracy of the apex of the range to intuitively reflect the performance of the sensor. (5) Sampling frequency/sampling period: frequency refers to the number of measurements per second. The higher the frequency, the shorter the time it takes to make a measurement. The shorter the measurement time, the more suitable it is for the detection of high-speed moving objects. (6) Average sampling times: even in the static state, there will be slight measurement fluctuations. At this time, multiple measurements are required to calculate the average number to make the measured value stable and accurate.Figure8. Laser SensorIV Laser Distance SensorLaser ranging is one of the earliest applications of the laser. This is because the laser has many advantages such as strong directivity, high brightness, and good monochromaticity. Before 1965, the Soviet Union used a laser to measure the distance between the earth and the moon (384401km) with an error of only 250m. In 1969, the Americans landed on the moon with a retro-reflector on the lunar surface. They also used a laser to measure the distance between the earth and the moon, with an error of only 15cm. The basic principle of using laser transmission time to measure the distance is to determine the target distance by measuring the time required for the laser to travel to and from the target.Related recommendation: Proximity SensorFigure9. Laser Distance Sensor4.1 Classification of Laser Distance Sensors Laser distance sensor technology is divided into absolute distance measurement method and micro displacement measurement method according to the measurement range. Subdivided according to the measuring method, the absolute distance ranging method mainly includes pulse laser ranging and phase laser ranging, and the micro displacement measuring method mainly includes triangulation laser ranging and interferometric laser ranging.4.2 Measuring Principle of Different Laser Distance Sensors(1) Pulse Laser Distance SensorA pulse laser with a very short duration is emitted by a pulsed laser, and after reaching the target to be measured after the distance to be measured, part of the energy will be reflected back. The reflected pulsed laser is called an echo. The echo returns to the rangefinder and is received by a photoelectric detector. According to the interval between the main wave signal and the echo signal, that is, when the laser pulse travels from the laser to the target to be measured, the distance of the target to be measured can be calculated.  (2) Phase laser Distance SensorThe emitted laser light is emphasized, and the phase change of the modulated signal is used when the laser is propagated in space. According to the wavelength of the modulated wave, the distance represented by the phase delay is calculated. That is, the indirect method of phase delay measurement is used instead of directly measuring the time required for the round trip of the laser to achieve distance measurement. The accuracy of this method can reach the millimeter level.Figure10. Working Principle of Laser Distance Measuring Device (3) Triangulation Laser Distance SensorAs mentioned above, this measurement principle is that the light emitted by the laser is focused on the surface of the measured object after being focused by the condensing lens, and the receiving lens receives the scattered light from the incident light spot and images it on the photoelectric  position detector On the sensitive side. When the object moves, the relative distance of the object movement is calculated by the displacement of the light spot on the imaging surface. The resolution of triangulation laser ranging is very high, which can reach the order of microns.   Figure11. Triangulation Principle (4) Interferometric Laser Distance SensorBy moving the measured target and measuring the coherence, the distance increment measurement is completed by counting, so the sensitivity of the interferometric measurement is very high, which can reach the nanometer level.4.3 Application of Laser Distance SensorThe laser distance sensor is mainly used for: monitoring the position of moving objects; measuring the railway contact network, measuring the boundary of buildings; measuring unsuitable objects; industrial automation and intelligent production management; vehicle speed and flow statistics; industrial monitoring signal trigger control; tower crane XY positioning of crane; automatic target distance control; monitoring of ship's safe docking position; positioning of container; measurement of vehicle's safe distance; measurement of overhead cable and height limitation; measurement of width of boxes on conveyor belt.V Laser Sensor Application Case(1) Over-limit detection of vehicle width and heightThe laser sensor is used for rapid measurement, the network core of the PC industrial control computer and the visual programming software VB are used for real-time data transmission and processing, and the friendly interface control software is also designed. Field test data shows that the system has good real-time performance and high measurement accuracy, and has certain practical value. (2) Expressway toll stationUsed in highway toll stations to count and protect vehicles. Malaysian Teras has applied hundreds of BEA laser sensors to its manual and automatic toll station systems. The laser sensor uses the time-of-flight (TOF) measurement principle, which can form 4 planes in the detection area to detect the vehicle. At the same time, the product also has functions such as anti-collision and vehicle safety protection. Compared with the traditional light curtain, the laser sensor has the advantages of high sensitivity, high accuracy, easy installation, high cost performance and strong stability. (3) Google's second-generation unmanned vehicleIn addition to the laser sensor on the top, Google’s second-generation driverless car prototype is still quite obvious, and the other sensors are set very concealed. The front, rear and sides of the vehicle are clearly marked with the Google unmanned vehicle logo. The driving principle of Google's unmanned vehicle is to continuously collect various accurate data of the vehicle itself and the surroundings through many sensors installed around the car, analyze and calculate it through the processor in the car, and then control the driving of the car according to the calculation results . Unmanned vehicles will use GPS equipment and sensors to accurately locate the vehicle's position and speed, and judge pedestrians, vehicles, bicycles, signal lights and many other objects around it.Figure12. Google's Self-driving CarThe roof of this Lexus is equipped with a 360° rotating laser holographic sensor, which can sense the front, side and rear conditions of the car almost simultaneously. The data collected by the sensor will be input to the processor located on the right rear side of the vehicle through the green data line. This laser sensor can also allow unmanned vehicles to be accurately positioned globally. The original L-shaped Lexus logo on the front of the car was also removed and replaced with a radar sensor; it was used to measure the distance ahead and the speed of the vehicle in order to determine the condition of the vehicle ahead and control the safe acceleration and deceleration of the vehicle. The wheel hub of the tire is also equipped with a position sensor, which is used to detect wheel rotation and help the vehicle to locate. The heart of Google's unmanned vehicles-the processor is located on the right rear side of the vehicle, the data information from each sensor will be transmitted here through the data wire, and analyzed and processed through the software in order to accurately sense and judge the difference between the unmanned vehicles object. In addition to analyzing and judging the current position of objects around the unmanned vehicle, the unmanned vehicle also needs to be calculated by software to accurately predict the possible next position of each object. Finally, the unmanned car will make safe driving decisions based on all the collected data, including controlling the speed of the car and the surrounding distance. VI FAQ1. How does laser sensor work?The basic principle is optical triangulation using a CMOS linear imager. A diffuse triangulating laser distance sensor transmits a laser through a lens and to the target, which reflects the light back to the sensor. A lens focuses this reflected light into a small spot onto the CMOS linear imager. 2. What is the use of laser sensors?The definition of a laser sensor is, it is an electrical device used to sense minute objects and precise positions. This sensor uses a laser to produce light within a straight line. Its visible ray mark of the laser makes the arrangement very simple. Laser light includes light waves with similar wavelengths. 3. What are the types of laser sensors?Laser distance sensors.Displacement sensors.Laser projectors.Laser light curtains.Laser photoelectric sensors.Positioning lasers.Laser edge detection sensors. 4. Are laser sensors dangerous?Improperly used laser devices are potentially dangerous. Effects can range from mild skin burns to irreversible injury to the skin and eye. The biological damage caused by lasers is produced through thermal, acoustical and photochemical processes. 5. Is a laser a sensor?A laser sensor uses a 'laser' to emit light in a straight line. Its visible beam spot makes alignment and positioning very easy. Since the light beam is focused, the sensor can be installed without worries about stray light. The major types of laser sensors include reflective, thru beam, and retro-reflective. 6. What is the range of the laser sensor?Laser distance sensors are designed for non-contact distance measurements: laser gauges for measuring ranges up to 10m, laser distance sensors for up to 3,000m. 7. What is CMOS Laser Sensor?A CMOS image sensor combines with a step-less laser power adjustment algorithm to produce stable detection of all types of workpieces from black rubber with low reflectivity to stainless steel and other highly glossy materials. 8. Which laser sensor is used for measuring very long distances?LDM301 laser distance sensor series – fast measurement of long distances. The laser distance sensors of the LDM301 series use a measured time-of-flight principle to measure distances of 300 m for natural surfaces and 3,000 m for reflective surfaces. 9. How does a laser sensor measure distance?The distance measurement is based on the triangulation principle. The laser beam strikes the object as a small point. The receiver of the sensor (photodiode line) detects the position of this point. The angle of incidence changes according to the distance, and thereby the position of the laser point on the receiver. 10. How accurate are laser distance sensors?Compared to other types of laser sensors, OM70 sensors feature one of the thinnest beam shapes, helping to ensure a more precise measuring focus. For example, most point-type lasers typically only go down to 0.2mm x 0.75mm whereas the OM70 goes down to 0.05mm x 0.05mm. 

IntroductionThe application of communication power source centralized monitoring technology in communication power supply indicates that the maintenance and management of communication power supply is changing from manual management mode to machine mode. The following is its purposes: (1) adapt to the development of communication technology; improve the maintenance and management of communication power supply equipment.(2)improve the power supply quality of communication power supply, making the power supply system have higher reliability and economy.(3) take full advantage of the computer technology to make the management of power supply equipment more automatic and intelligent.(4) realize less manual work of communication power supply equipment monitoring.(5) improve the maintenance efficiency and reduce maintenance costs. At present, the development of communication power centralized monitoring technology and the implementation of the monitoring system have entered a new era.As for function, in order to meet the requirement of machine monitoring than manual work, it emphasizes the quick response and fault alarm accuracy to the fault events of the power equipment. At present, the power supply monitoring system is continuously improved and developed based on its basic functions, such as telecontrol, teleindication and telemetering, monitoring information query, data storage and recording, real-time historical trend, system configuration, remote operation, password management, support for networking, etc. 1. Intelligent Device AccessBecause there are many kinds of communication power supply equipment, for intelligent equipment, even the same kind of equipment also have different protocols because of different manufacturers, in addition, there are many suppliers of power supply equipment, thus there are more kinds of protocols. In the process of implementation of the monitoring system, to make better use of the resources of intelligent equipment, the intelligent device is directly connected to its monitoring system through the conversion of the communication interface and protocol. The communication interface conversion basically belongs to the hardware conversion between RS-232, RS-485 and CAN, which is easy to realize. In the past, the conversion of communication protocols has always been a thorny problem in the implementation of monitoring systems. At present, this problem has been preliminarily resolved. On the one hand, most power supply equipment manufacturers can provide the communication protocol of their equipment actively, on the other hand, the intelligent equipment receives agreement officially. Both of them make the protocol conversion easily. At present, if the protocol and communication interface conversion is based on protocol converter, this method is connecting a protocol converter between an intelligent device and station monitoring host. One end is connected with the serial port of the intelligent device, another is connected with the serial port of the station monitoring host computer, thus the conversion of communication protocol and the communication interface is completed.In short, the protocol converter is a microcomputer system with CPU, EPROM, RAM, serial communication port and so on. The protocol conversion generally has two conditions: firstly, there are at least two serial ports which match with the serial ports of the converted intelligent device and the local station monitoring sovereignty respectively; secondly, the conversion software is solidified in the EPROM of the protocol conversion when the communication protocol of the intelligent device is converted into the host protocol of the local station monitoring. This method is more effective for multiple intelligent devices with different protocols connected to one monitoring host at the same time. Another way is putting the protocol conversion function in the station monitoring host, this method is not often used in practice because it is only suitable for connecting intelligent devices with a single subject protocol to a monitoring host. If there are too many kinds of protocols in a monitoring host, the monitoring host will be overburdened and its normal work will be affected. At the same time, it will bring about problems for the development of to monitoring host software. In addition, the unified communication protocol provides a better solution for intelligent device access. 2. Reliability of the Monitoring SystemAs a result of new-technology and high-quality devices are more widely used in the production of communication power supply equipment, the reliability and automation of the monitoring system have been greatly improved. For example, switching power supply equipment, UPS, diesel generator sets and other intelligent devices, as well as non-intelligent devices such as VRLA storage batteries which are widely used now. All have high reliability to improve the monitoring management and provide better conditions for the purpose of less manual work. Therefore, based on the continuous improvement of the performance of the power supply monitoring system, the reliability of the monitoring system should be improved. 3. Perfecting the Self-checking Function of the Monitoring SystemIn order to make the monitoring system play its role more effectively, it is necessary to continuously improve the basic functions of the monitoring system, meanwhile, pay attention to the use of the advantages of computer data processing, developing and improving the high intelligent performance. Fundamentally change the traditional maintenance mode, using the monitoring technology effectively.The implementation of the monitoring system is based on the new maintenance mode. That is, taking the region as the monitoring management center to monitor and manage the corresponding stations and stations. Urban monitoring and management center unifies its regions and manages them. The difference between the manual and mechanized management modes except for the maintenance, the greater difference is computer realize the automatically real-time monitoring. For example, when the power supply equipment fails, The monitoring system will make a quick response and timely report to the corresponding management center. To adapt to this kind of computer monitoring and management mode, it is necessary to change the traditional maintenance mode fundamentally. Using the computer monitoring system, which is characterized by the real-time monitoring of the power supply equipment, but it requires to read the meter at intervals within the period of time, which is stored and printed in the form of a daily report form. These statements should also be kept for two to three years. This method takes up the large resources of the monitoring system, and the data is rarely used in practice. In the face of these problems, the monitoring system in certain functions should be reconsidered:(1) On the basis of continuously improving the reliability of the controlled equipment (power supply equipment), the safety and reliability of the monitoring system can be improved comprehensively.(2) From the overall consideration of the controlled equipment and the monitoring system, since the security and reliability of the power supply equipment can be basically guaranteed (the reliability requirements of power supply equipment are: switching rectifier MTBF> 50,000h, VRLA battery MTBF> 350,000h. the reliability index of AC/DC distribution equipment is higher as required, and the reliability index of the monitoring system should be MTBF> 100000h), the implementation of the monitoring system should be simplified, practical and highly intelligent. At the same time, it should ensure the accuracy and rapidity of the alarm and warning performance of the monitoring system, also with the intelligent optimization of statistical analysis. The continuous improvement of the function makes the reading meter within time period become less significant.(3) renew the traditional maintenance concept and establish a new maintenance system.Therefore, another important task of the future monitoring system is to fundamentally change the traditional maintenance mode. Making more effective use of monitoring technology to impel the power monitoring system play a greater role in the management of communication power supply maintenance. 4. Network Access Detection of the Monitoring SystemTesting the monitoring system is difficult and will be limited by the following conditions:(1) to carry out the inspection of the monitoring system, it is necessary to have a standard basis for the items, indicators, conditions, and methods. And there are some technical requirements of the monitoring system at present, but as the standard basis of monitoring system detection is far from enough.(2) compared with the general power supply equipment, the monitoring system adopts more computer technology, and emphasizes the network and function of the system, and the real time of the system software, so it is difficult to evaluate the technical performance of monitoring system.(3) A monitoring system is a large real-time network system, which has certain capacity features (including software and hardware capacity). The realization of various performance indicators is meaningful only when the capacity is full, but it is impossible to establish a full capacity system when having these detecting indices.(4) restricted by the mode of communication, communication conditions and other aspects. ConclusionFrom the above situation, we can see that the implementation of the monitoring system is indeed facing great difficulties. Even that, the monitoring system is tested through certain methods to reach the maximum approximation. It is necessary and meaningful to describe and evaluate the performance index of the monitoring system.You May Also LikeList of Basic Electronic ComponentsSwitching Power Supply Tutorial: 4V～16VWhat is A MCU’s internal Structure: Single Chip Micro-ComputerPCB Wring Tutorial: A/D converterDIY Community: Let's Make MonitoringHydroponic Grenhouse Monitoring and Control System

Radio Frequency Identification (RFID) technology has been developed rapidly in recent years. The key is an automatic identification technology which uses radio waves to communicate. Compared with the traditional recognition technology, it has the advantages of fast recognition, large data storage and data updatable.  This is a video about brief introduction to RFIDThe basic principle of the data communication is the electromagnetic coupling between the reader and the electronic tag affixed to the object. This article will take the RFID technology as the research object, analyzing the basic definition of RFID, the components of the system, the working principle, operating frequency, the main application examples and development trend of RFID technology. In this article, we will make some intorduction to RFID and analyze how it will develop in the future.  CatalogI What is RFID?II Structure of RFID system2.1 Basic components of RFID2.2 RFID middlewareIII Basic working principle of RFID   technologyIV RFID operating frequency4.1 Low frequency 4.2 High Frequency4.3 Ultra-high frequency4.4 Active RFID technologyV RFID practical application examples5.1 Necessity of applying RFID technology   to retail logistics5.2 Why to use RFID technology instead of   existing technology5.3 Application of RFID technology in   retail industryVI Development trend of RFID application   system6.1 More powerful system compatibility6.2 System networking6.3 Greater system data volume6.4 High frequency systemFAQI What is RFID?Radio Frequency Identification (RFID) technology, also known as electronic tag, is a communication technology that uses radio signals to identify specific targets and read and write related data. And there is no need to identify the mechanical or optical contact between the system and the specific target. It can achieve fast reading and writing, non-visual recognition, mobile recognition, multi-target recognition, locating and long-term tracking management. The recognition work is not affected by bad environment, and it can achieve fast reading speed, read information safe and reliable. Therefore, RFID technology has a wide range of application prospects. Radio frequency identification is a non-contact automatic identification technology. It can automatically identify the target object and obtain the relevant data through the radio frequency signal. The identification work can be applied to all kinds of bad environment. RFID is a simple wireless system with only two basic devices. It is used to control, detect and track objects. The system consists of an interrogator and many transponders.Due to the rapid development of RF technology, transponders are also called smart tags or tags. The RFID reader can communicate wirelessly with the electronic tag through the antennas, and can read and write the tag identification code and memory data. A typical reader includes a high-frequency module, a control unit and a reader antenna. II Structure of RFID system2.1 Basic components of RFIDRFID system mainly includes four parts: electronic tag, reader, antenna and application software. The following picture is the block diagram of the system:RFID system structureFrom the above diagram, we can see that there are input and output of data in the module of reader and electronic tag, and the energy and clock are also transmitted in the two modules.2.1.1 ReaderReader is a device for reading (or writing) tag information that can be designed to be hand-held or fixed type. Hand-held is a smaller type used by supermarket cashiers; Fixed is a stationary reader placed by a logistics company at the door when goods are stored in a warehouse. As soon as the object swept by, the scan was completed in an instant.Reader working model2.1.2 AntennaAntenna is used to transmit RF signals between tags and readers.2.1.3 TagsTags are made up of coupling elements and chips. Each tag has a unique electronic code attached to an object to identify the target object. The following picture is the query tag diagram of readers. Reader query tag diagram2.1.4 Application softwareApplication software is a part of RFID system, which is software developed for different needs. It can read, write and control electronic tags through readers, and process and count the collected data. 2.2 RFID middlewareIn the application program, the API can connect to the RFID reader and retrieve the data from the RFID tag through the universal application program interface which can be provided by middleware. RFID middleware acts as a bridge between RFID tags and applications.In this way, even when the FRID reader category or application changes, the application still doesn't need to make any changes. It just need to configure the middleware accordingly. This can reflect the flexibility and importance of middleware.Practical application of RFID middlewareThe benefits that the application of RFID middleware can be brought to an enterprise are as follows:- According to their own business requirements and actual usage, enterprises can import the required data into the application software by self-configuring the RFID middleware parameters, which can fully reflect the flexible characteristics of RFID middleware.- The import of RFID data only needs to change the setting of RFID middleware when some changes occur in enterprise application software.- If you need to increase the number of RFID readers, then enterprises only need to do some related RFID middleware settings. It doesn’t need to change any related procedures, which reduce unnecessary trouble, and save time.- It shortens the implementation cycle of RFID application, and enterprises can directly import the relevant data of RFID.  III Basic working principle of RFID technologyA complete RFID system is composed of three parts: reader, tag with transponder and application software system. Its working principle is: Reader sends out the energy of a radio wave at a specific frequency to drive the transponder, and the circuit will send out the internal data. At this time, the reader will receive the data in order and interpret them, then send it to the application for some corresponding processing.RFID working principleThe information exchange between the reader and the transponder is usually half-duplex communication mode. In this case, the reader can provide the passive transponder with energy, timing and other related contents by coupling. In practical application, the object recognition information can be collected, processed and transmitted remotely through Ethernet and so on. Transponder is the main information carrier of its system. At present, most of the transponders in the market are composed of coupling elements (including coils, microstrip antennas, etc.) and passive application units composed of microchips. The reader can control and process the information center according to the structure and technology of RFID system information. Its reader is usually composed of a transceiver module, a coupling module, an interface unit and a control module. IV RFID operating frequencyAt present, the operating frequencies of RFID products are divided into low frequency, high frequency, ultra high frequency and so on. RFID products with different frequencies will have different characteristics. 4.1 Low frequency (125KHz ~ 135KHz)Related operation at this frequency is mainly done by inductive coupling. There is a transformer coupling between the inductor coil and the reader coil. The voltage which can be induced in the antenna of the inductor can be rectified by the action of the relative alternating field of the reader. Features:- Apart from some related effects of metal materials, the general low-frequency system can penetrate any material, but it will not reduce its maximum possible reading distance.- Readers working at low frequencies have no special licensing restrictions on the entire planet.- Low-frequency products have different packaging forms. The disadvantage of the best package is that it is too expensive, but it has a service life of more than 10 years.- The frequency of the sensor working in low frequency ranges from 120KHz to 134 kHz. The wavelength of this band is about 2500m. 4.2 High frequencySensors at this frequency will no longer need a coil to wrap it up. Antennas can be made by etching or printing. The related operations of sensors are usually done by load modulation. That is, by turning on and off the load resistance on the inductor, the voltage on the reader antenna will be changed, which can realize the amplitude modulation of the antenna voltage with the remote inductor. If people use data to control load voltages on and off, the data can be transmitted quickly from the sensor to the reader.Features: - Apart from metallic materials, the wavelength of this frequency can pass through most materials, but it will reduce the reading distance. Sensors often need a distance away from the metal.- Although the magnetic field region at this frequency decreases rapidly , a relatively uniform read - write region can be produced.- The system has good anti-collision property and can read many electronic tags at the same time.- Sensors usually exist in the form of electronic tags. 4.3 Ultra-high frequencyThe ultra-high frequency system will transmit energy by electric field. The energy of the electric field will not decrease rapidly. The reading distance of UHF is relatively long, and the passive system can reach about 10m. It is mainly realized by capacitive coupling.Features: - This frequency band has a good reading distance, but it is difficult to define the reading region.- It has a particularly high rate of data transmission and can read a large number of related electronic tags in a very short time.- The radio waves in the UHF band cannot pass through many kinds of application materials, especially water, dust and other substances. For high-frequency electronic tags, however, the tags need not be separated from metals.- Tag antennas are usually in two forms: long stripes and tags. The antenna has two different shapes: linear and circular polarization. It is designed to meet the needs of different applications in the market. 4.4 Active RFID technologyActive RFID is characterized by large amount of data transmission, long communication distance, high reliability, low transmitting power and good compatibility. Compared with passive RFID, it has obvious technical advantages.The basic ideas of RFID technology are: By adopting advanced technical means, people can automatically identify and manage all kinds of objects and equipment in different states.As a new kind of automatic identification technology, RFID technology has a great potential space for development in China, and it has been applied and developed in radio technology. V RFID practical application examplesIn this chapter, we will mainly expound the logistics analysis of retail industry based on RFID technology.5.1 Necessity of applying RFID technology to retail logisticsThe benefits of using RFID technology are not limited to the benefits of retail itself. With the use of RFID technology to create a new revenue stream, government institutions can reduce the loss and enhance the safety and security. At the same time, logistics companies, library systems can also reduce inventory costs.The application of RFID technology in retail can obtain the following benefits:   - Increase project securityTag items only allow objects to be tracked in a specified range or device. RFID technology can also improve the efficiency of inventory management. After all, inventory management is often a time-consuming and exhausting business for retailers.  - Serialization DataEach item has its unique identification number, so it is convenient to distinguish it from other items.  - Real time information flowThe changing state of a project can be quickly updated throughout the supply chain.  - Reduced manual participationRFID technology can track objects automatically without manual counting , data acquisition and bar code scanning , which can save labor cost and human error. The RFID technology provides a real-time visualization technology that allows inventory managers to monitor inventory supplies in real time. This reduces inventory costs and keeps inventory at an optimal level, which avoids shortage and other phenomena at the same time. 5.2 Why to use RFID technology instead of existing technologyThe question now is: why did retail change existing technology by adopting RFID? RFID technology is very similar to the existing bar code technology and non-contact memory. The use of new technologies can bring financial benefits (such as saving money) and can solve some practical problems that can not be solved by the existing technology. Compared with other automatic recognition techniques, RFID has significant advantages. 5.3 Application of RFID Technology in Retail industryRFID technology has been used in the retail industry such as smart shelf. The smart shelf is a kind of shelf which can prevent the phenomenon of product shortage. The shelf combines the RFID reader. Each unit shelf has a RFID tag that allows readers to track the inventory of their products. The main purpose of smart shelf is to support the replenishment at any time and to keep the shelves never out of stock, thus it has been widely used in retail industry and libraries. On one hand, it provides customers with information about the products; on the other hand, it provides inventory information for retail owners and can accurately locate the goods. The purpose of these applications is to offer better and more effective service to them. The use of these technologies will not be limited. It can make customers feel more effective and easier to shop.VI Development Trend of RFID Application systemIt can be predicted that future RFID systems will have the following technological trends: 6.1 More Powerful System CompatibilityAt present, because of the disunity of standards, products from many manufacturers are incompatible with each other. Therefore, it is required that the system should have a very strong compatibility, so that it can deal with the products of multiple manufacturers. 6.2 System NetworkingIn many applications, the data collected by different systems need to be processed uniformly, and then provided to users for use, which requires the management of RFID systems on a networked basis. The aim is to realize the remote control management of the system. 6.3 Greater System Data VolumeThe future RFID system will deal with a large amount of data, so it is necessary for the system to have a stronger data storage capacity and data processing capacity. 6.4 High frequency systemThe UHF RFID system has many advantages compared with the low frequency system, such as small size, long recognition distance, repeatable reading and writing, and no forgery. Therefore, with the decrease of manufacturing cost, the application of UHF system will be more extensive.  FAQ 1. What is RFID used for?Radio Frequency Identification (RFID) is the wireless non-contact use of radio frequency waves to transfer data. Tagging items with RFID tags allows users to automatically and uniquely identify and track inventory and assets. 2. What is RFID and how it works?RFID is a method of data collection that involves automatically identifying objects through low-power radio waves. Data is sent and received with a system consisting of RFID tags, an antenna, an RFID reader, and a transceiver. 3. What RFID means?Radio Frequency Identification (RFID) refers to a wireless system comprised of two components: tags and readers. The reader is a device that has one or more antennas that emit radio waves and receive signals back from the RFID tag. 4. Is RFID harmful to human?It is a non-ionizing type of radiation, but some researches show that it could have a negative impact on the human body in a long-term period [11, 12]. So, for the safety reasons, manufacturers of the RFID systems have limited the range of the RFID antennas used in their systems. 5. Is RFID tag and FASTag same?FASTag is a device that employs Radio Frequency Identification (RFID) technology for making toll payments directly while the vehicle is in motion. FASTag (RFID Tag) is affixed on the windscreen of the vehicle and enables a customer to make the toll payments directly from the account which is linked to FASTag. 6.What is RFID and its advantages?RFID technology automates data collection and vastly reduces human effort and error. RFID supports tag reading with no line-of-sight or item-by-item scans required. RFID readers can read multiple RFID tags simultaneously, offering increases in efficiency. 7. Why is RFID bad?Some negative effects are that its deadly, if RFID tags combine with static electricity you can die. Another negative effect is that the government is slowly taking away surviving resources and giving ultimatums, such as if you don't get the RFID tracking chip your public assistance will be terminated. 8.What are the disadvantages of RFID?a. Materials like metal & liquid can impact signal.b. Sometimes not as accurate or reliable as barcode scanners.c. Cost – RFID readers can be 10x more expensive than barcode readers.d. Implementation can be difficult & time consuming. 9.How do I charge my RFID FASTag?In order to recharge your FASTag sticker, just hit the Add Money option in your Paytm app. FASTag will automatically reserve some amount from your wallet, which can be used at toll plazas later. Do note that FASTag can be used only after 20 mins of adding money to the Paytm Wallet. 10. Can I use existing RFID for FASTag?If a vehicle already has an RFID tag, it might already be activated. When you buy the vehicle, RFID tag payment was also done. It might also have a minimum balance of INR 100 or 200 as is required by the bank. You can recharge it with your Customer ID or Wallet ID of FASTag. 11. How does RFID work without power?Passive RFID tags have no power of their own and are powered by the radio frequency energy transmitted from RFID readers/antennas. The signal sent by the reader and antenna is used to power on the tag and reflect the energy back to the reader. 12. What are the types of RFID tags?RFID tags can be grouped into three categories based on the range of frequencies they use to communicate data: low frequency (LF), high frequency (HF) and ultra-high frequency (UHF). Generally speaking, the lower the frequency of the RFID system, the shorter the read range and slower the data read rate. 13.How do I know if I have an RFID chip?The best way to check for an implant would be to have an X-ray performed. RFID transponders have metal antennas that would show up in an X-ray. You could also look for a scar on the skin. Because the needle used to inject the transponder under the skin would be quite large, it would leave a small but noticeable scar. 14. Does RFID require power?Active RFID tags possess their own power source – an internal battery that enables them to have extremely long read ranges as well as large memory banks. Typically, active RFID tags are powered by a battery that will last between 3 - 5 years, but when the battery fails, the active tag will need to be replaced. 15. What is the difference between a QR code and RFID?QR codes must always be “read-only”, whereas RFID tags can be “read-write”, depending on the radio frequency that's being used. ... So, not only are RFID tags futuristic and have more uses than QR tags, they also have many more applications. The read range is far superior for an RFID tag.  

SummaryResearchers at TU Wien have succeeded in developing a method for the controlled manufacture of porous silicon carbide. Silicon carbide has significant advantages over silicon; it has greater chemical resistance and can therefore be used for biological applications, for example, without any additional coating required.Extremely fine porous structures with tiny holes – resembling a kind of sponge at nano level – can be generated in semiconductors. This opens up new possibilities for the realization of tiny sensors or unusual optical and electronic components. There have already been experiments in this area with porous structures made from silicon.To demonstrate the potential of this new technology, a special mirror that selectively reflects different colors of light has been integrated into a SiC wafer by creating thin layers with a thickness of approximately 70nm each and with different degrees of porosity. “There is a whole range of exciting technical possibilities available to us when making a porous structure with countless nano holes from a solid piece of a semiconductor material,” says Markus Leitgeb from the Institute of Sensor and Actuator Systems at TU Wien. Leitgeb developed the new material processing technology as part of his dissertation with Professor Ulrich Schmid in cooperation with CTR Carinthian Tech Research AG and sponsored by the Competence Centers for Excellent Technologies (COMET) program.“The porous structure influences the manner in which light waves are affected by the material. If we can control the porosity, this means we also have control over the optical refractive index of the material.” This can be very useful in sensor technology – for example, the refractive index of tiny quantities of liquid can be measured using a porous semiconductor sensor, thus allowing a reliable distinction between different liquids. Another attractive option from a technical and application-oriented perspective is to first make certain areas of the SiC wafer porous in a highly localized manner, before depositing a new SiC layer over these porous areas, and then causing the latter to collapse in a controlled manner – this technique produces microstructures and nanostructures which can also play a key role in sensor technology.  However, in all these techniques it is crucial that the appropriate starting material is selected. “Until now, silicon has been used for this purpose, a material with which we already have a lot of experience”, says Professor Schmid. Silicon also has significant drawbacks, however; under harsh environmental conditions, for example in extreme heat or in alkaline solutions, structures made of silicon are attacked and rapidly destroyed. Therefore, sensors made of silicon are often not suitable for biological or electrochemical applications. For this reason, at TU Wien, attempts have been made to achieve something similar with the semiconductor silicon carbide, which is biocompatible and considerably more robust from a chemical perspective. Some special tricks were required, however, in order to produce porous structures from silicon carbide. THE COLOR-SELECTIVE MIRRORFirst, the surface is cleaned, and then partially covered with a thin layer of platinum. The silicon carbide is then immersed in an etching solution and exposed to UV light, in order to initiate the oxidation processes. This causes a thin porous layer – initially 1μm thick – to form in these areas that are not coated with platinum. An electrical charge is then also applied in order to be able to precisely set the porosity and the thickness of the subsequent layers. Here, the first porous layer promotes the formation of the first pores when the electrical charge is applied.“The porous structure spreads from the surface further and further into the interior of the material”, explains Markus Leitgeb. “By adjusting the electrical charge during this process, we can control what porosity we want to have at a given depth.” In this way, it was possible to produce a complex layered structure of silicon carbide layers with higher and lower levels of porosity, which is finally separated from the bulk material by applying a high voltage pulse. The thickness of the individual layers can be selected such that the layered structure reflects certain light wavelengths particularly well or allows certain light wavelengths to pass through, resulting in an integrated, color-selective mirror. “We have thus demonstrated that our new method can be used to reliably control the porosity of silicon carbide on a microscopic scale”, says Ulrich Schmid. “This technology promises many potential applications, from anti-reflective coatings, optical or electronic components and special biosensors, through to resistant supercapacitors.”