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Application of ultrasonic sensor

The main materials of ultrasonic sensor include piezoelectric crystal (electrostrictive) and nickel iron aluminum alloy (magnetostrictive). The electrostrictive materials include lead zirconate titanate (PZT), etc. The ultrasonic sensor composed of piezoelectric crystal is a reversible sensor, which can convert electrical energy into mechanical vibration to generate ultrasonic, and when it receives ultrasonic, it can also convert into electrical energy, so it can be divided into transmitter or receiver. In real life, it is not difficult to find the application of ultrasonic sensors. With the rapid development of science and technology, the scope of application of ultrasonic sensors has become more and more extensive. In the history of human development, the application of ultrasonic sensors is everywhere, as long as the human can imagine, it can step in. The discovery of hybrid rice has greatly shortened the distance between China and other countries and injected vitality into China's economy. Ultrasonic sensors are so widely used. Do you really know its principle and application range? Ultrasonic sensor is developed by using the characteristics of ultrasonic wave. Ultrasonic wave is a mechanical wave whose vibration frequency is higher than that of sound wave. It is generated by the vibration of the energy exchange chip under the excitation of voltage. It has the characteristics of high frequency, short wavelength, small diffraction phenomenon, especially good directionality, and can be transmitted directionally as a ray. Ultrasound has great penetrating power for liquids and solids, especially in sunless solids, which can penetrate tens of meters deep. Ultrasound will reflect when it encounters impurities or interfaces to form echo, and it will generate Doppler effect when it encounters moving objects. Therefore, ultrasonic testing is widely used in industry, national defense, biomedicine and other fields.

2021

01-06

Test method of ultrasonic sensor

As a detection device, the ultrasonic sensor can not only sense the measured information, but also transform the detected information into electrical signals according to certain rules, or other required forms of information output. However, the output signal of the sensor should be easy to transmit, process, store, display, record and control information. With the development of electronic and microelectronic technology, the development of the sensor is also changing with each passing day. There are more and more applications and types of sensors in production and life. For example, wireless sensor, radar sensor, infrared light temperature sensor, geomagnetic object detection sensor, etc. Ultrasonic sensor is one of the most widely used sensors. Ultrasonic sensor uses the characteristics of ultrasonic technology for sensing. The application of sensor detection based on the volume, material, and movability of the detected object includes: whether there is detection: whether the object is detected/in place/count; Color detection: detect the color/concentration of objects; Dimension measurement: length/width/height/thickness/temperature/distance; Deviation correction inspection: appearance inspection. However, the ultrasonic sensor adopts different detection methods. The common detection methods are as follows: Penetrating type: the transmitter and receiver are located on both sides respectively. When the detected object passes between them, it will be detected according to the attenuation or occlusion of the ultrasonic wave. Limited distance type: the transmitter and receiver are located on the same side. When there is a detected object passing within the limited distance, the detection is carried out according to the reflected ultrasonic wave. Regression reflection type: the transmitter and receiver are located on the same side, and the detection object is taken as the reflection surface, and the detection is carried out according to the attenuation of the reflected wave. Limited range type: the transmitter and receiver are located at the center of the limited range, the reflector is located at the edge of the limited range, and the attenuation value of the reflected wave when there is no object to be detected is taken as the reference value. When there is an object to be detected in the limited range, the attenuation value is compared with the reference value according to the attenuation condition of the reflected wave for detection.

2021

01-06

Ultrasonic sensor is the choice for short distance application

Ultrasound refers to signals that are beyond the range of human hearing, usually in the range of 40 to 70 kHz. These signals are used like radar. They will radiate to the target and reflect back to the source. They are cheap, flexible, and especially suitable for short-range applications, especially the design of automobiles, home and industrial robots. Ultrasonic sensors are sometimes used in combination with microwave/millimeter wave radars and cameras to provide different but complementary views of the surrounding environment in automotive and industrial applications. If you are looking for a sensor that can not only detect the presence of the target, but also tell you how far the target is, then ultrasound may be your ideal choice. Ultrasonic signal refers to the signal above the human hearing range, about 30 to 480 kHz. For ultrasonic sensing, the most widely used range is 40 to 70 kHz. Frequency determines the range and resolution; Lower frequencies produce the maximum sensing range. The common frequency is 58 kHz, the measurement resolution is 1 cm, and the maximum range is 11 meters. At 300 kHz, the resolution may be as low as 1 mm, but the maximum distance of this frequency range is about 30 cm. The ultrasonic transceiver radiates the signal through the piezoelectric transducer. When the signal hits the target, it will generate a reflection signal. The signal is received at the transceiver. The transceiver measures the time of transmission and return, and then calculates the distance using the sound velocity in the air. The sound speed in free space is 1120, which varies with temperature and other surrounding factors, but it is a good average value for range calculation. Ultrasonic technology has entered a wide range of applications. The largest areas may be proximity detection and distance measurement. Other include liquid level detection in tanks, flow measurement systems and imaging products. Most of the newer applications are for consumer electronics, Automotive and industrial/robotics.

2021

01-06

Application of area sensor

The area sensor refers to the device or device that can sense (or respond) the specified measured signal and convert it into usable signal output according to certain rules. The sensor is usually composed of the sensitive element directly responding to the measured signal, the conversion element that generates usable signal output, and the corresponding electronic circuit. The sensor that can collect the area signal is called the area sensor. The principle of the area sensor, commonly known as "light curtain" or "grating", is similar to that of the photo-electric sensor of the opposite type. It is detected by detecting the optical axis between the transmitter and receiver of the opposite object. The difference is that the photoelectric sensor can detect the presence or absence of an object at a certain point, while the area sensor can detect the object in a plane area. If ordinary photoelectric sensors are used to detect the presence or absence of objects within a certain area, the required number of photoelectric sensors need to be installed in parallel. Obviously, the installation and adjustment of area sensors is much more convenient than that of installing the optical axes of many photoelectric sensors in the same plane. Regional sensors can be widely used in: food and beverage, packaging, electronic components and equipment, warehousing, machine tool industry, metal parts processing industry, logistics express sorting line and other automated production lines. In addition, the solid aluminum alloy shell and IP67 protection grade can calmly cope with various harsh environments such as moisture, oil, dust and so on. Foshan Qiwei Electric Technology Co., Ltd. is a high-tech enterprise integrating sales, technical services, engineering and research and development. It provides automation engineering technical services and complete solutions, and also provides intelligent manufacturing and digital chemical plant solutions, realizing the "one-stop" service of industrial control automation.

2021

01-06

How to use the proximity switch?

Proximity switch refers to the position switch that can make the switch move without mechanical contact and pressure when the object approaches the sensing surface of the switch to the action distance, thus driving AC or DC electrical appliances or computer equipment to make the switch move. Proximity switch is a switch type sensor (i.e. contactless switch), which has the characteristics of travel switch and microswitch, and has the sensing performance, reliable action, stable performance, and fast frequency response, It features long service life, strong anti-interference ability, and has the advantages of waterproof, shockproof, corrosion resistance, etc. The main products are inductive, capacitive, Hall, AC and DC. Proximity switch, also known as near contactless switch, is an ideal electronic switch sensor. When the metal detector approaches the sensing area of the switch, the switch can be contactless, pressureless, and spark-free. It can quickly send out electronic instructions and accurately respond to the position and travel of the action mechanism. That is, it is used for ordinary travel control, with its positioning accuracy, operating frequency, service life, installation and adjustment convenience, and the ability to adapt to harsh environment, Compared with general mechanical travel switch, it is incomparable. Proximity switch is widely used in machine tool, metallurgy, chemical industry, light textile, printing and other industries. The system can be used as limiting, counting, positioning control, automatic protection and other links. The proximity switch has the advantages of long service life, reliable operation, high precision of repeated positioning, no mechanical wear, no spark, no noise, and strong anti-vibration ability. So far, the application range of proximity switch is becoming wider and wider, and its development and innovation speed is also very fast.

2021

01-06

How to select photoelectric switch?

Photoelectric switch is a kind of sensor, which converts the change of light intensity between the transmitting end and the receiving end into the change of current to achieve the purpose of detection. Photoelectric sensor adopts integrated circuit technology and SMT surface mounting technology to manufacture a new generation of photoelectric switch device, which has intelligent functions such as delay, broadening, external synchronization, mutual interference resistance, high reliability, stability of working area and self-diagnosis, This novel photoelectric switch is an active photoelectric detection system-type electronic switch using pulse modulation. The cold light sources used include infrared light, red light, green light, blue light, etc. It can quickly and control the state and action of various solids, liquids, transparent bodies, black bodies, soft software, smoke and other substances without contact and damage. Let's take a look at how to select photoelectric switch: Photoelectric switches have been applied in many fields, such as level detection, liquid level control, product counting, width discrimination, speed detection, fixed length shearing, hole recognition, signal delay, automatic door sensing, color code detection, punch and shearing machine, and security protection. In addition, the use of the concealment of infrared ray can also be used as anti-theft warning in banks, warehouses, stores, offices and other necessary occasions. The photoelectric switch is simple, small and durable. Foshan Qiwei Electric Technology Co., Ltd. is a high-tech enterprise integrating sales, technical services, engineering and research and development. Based on years of industry experience, the company strives for change and progress, and provides automatic engineering technical services and complete solutions, as well as intelligent manufacturing and digital chemical plant solutions, realizing the "one-stop" service of industrial control automation.

2021

01-06

What is the position of machine vision system in automation?

In automatic production, machine vision system detection is very important, because machine vision detection can replace manual inspection and realize automatic inspection. What is the position of machine vision system detection in the entire automation industry? In modern industrial automation production, it involves various inspection, measurement and part identification applications. For example, the size inspection of auto parts and the automatic assembly integrity inspection, the electronic assembly line component positioning, the beverage bottle cap printing quality inspection, and the bar code and character recognition on the product packaging. The common characteristics of these applications are continuous batch production and high requirements for appearance quality. Usually, this highly repetitive and intelligent work is done by the naked eye, but in some special cases, such as accurate and rapid measurement of small size, shape matching and color recognition, the naked eye can not maintain stability at all, and other physical quantity sensors can not be implemented. With the intensification of industry competition, the company's control of product quality is not even allowed to have a 0.1% defect, Therefore, it is necessary to ensure 100% inspection qualification rate (i.e. "zero defect") to ensure the continuous and stable growth of products. Therefore, people began to consider using CCD cameras to capture images and send them to computers or special image processing modules. Through digital processing, the size, shape, color, etc. were determined according to pixel distribution, brightness, color and other information. This method combined the rapidity and repeatability of computer processing with the high intelligence and abstract ability of naked eye vision, thus forming the concept of machine vision detection technology. Machine vision system inspection technology is a new testing technology based on computer vision research. Different from the visual pattern recognition and visual understanding of computer vision research, visual inspection technology focuses on the measurement of object geometric size and position, such as the three-dimensional dimension of the white body, rapid measurement of the three-dimensional shape of the mold, etc., the coaxiality measurement and coplanarity measurement of large workpiece. In addition, The inspection system of machine vision technology can also automatically detect the entire product, which is also very important for controlling product quality and ensuring product quality. With the needs of market development in various industries, in order to better base on the market and enhance the competitiveness of enterprises, more and more enterprises are focusing on the continuous introduction of high-tech. In today's increasingly progressive industrial automation, machine vision technology is also increasingly widely used in the industry, and is increasingly recognized and favored by users.

2021

01-06

What is the difference between machine vision system and machine vision sensor?

The machine vision sensor is designed to facilitate installation and deployment, so that factory personnel can usually complete the setting and configuration without a lot of external assistance. If the imaging work only needs simple/no judgment, then the company may need a vision sensor, while the machine vision system needs more professional knowledge and needs to invest a lot of time and money to complete the configuration, installation and training, Usually, companies will rely on third-party integrators with rich professional experience in visual systems. What are the differences between them? Let's understand: 1. The visual sensor is responsible for performing simple detection, such as answering simple "yes" questions on the production line. 2. The vision system is responsible for completing some complex tasks, such as helping the robot arm to weld parts in an automated factory. 3. The machine vision sensor can collect the light wave of the camera lens and convert the light data into pixels that generate digital images together with the digital signal processor (DSP). The software analyzes the pixel pattern and displays the key data of the object taken. Many automatic factory tasks require simple and direct vision sensor data: • Presence or absence - determine whether there are parts in the sensor's field of vision? If the sensor answers yes, the machine vision software allows the part to be moved to the correct position in the production process. • Inspection - determine whether the parts are damaged or defective? If the sensor sees a defect, the part will be removed from production. • Optical character recognition (OCR) - determine whether the part has a specific word or text? Answering this question helps the automated system sort products by brand name or product description.

2021

01-06

Composition of industrial machine vision system

With the development of industrial automation, the application of industrial machine vision system will also be more and more extensive. In addition, the rapid development of digital image sensors, CMOS and CCD cameras, DSP, FPGA, ARM and other embedded technologies, image processing and pattern recognition technologies will also bring a huge boost to the development of machine vision inspection. Here is a brief introduction of the main components of industrial machine vision system: 1. Camera and optical components This category usually contains one or more cameras and lenses (optical components) for photographing the detected object. According to the application, the camera can be based on the following standards: black and white, composite color (Y/C), RGB color, non-standard black and white (variable scan), step scan or line scan. 2. Lights The light of industrial machine vision system is used to illuminate components, so as to capture better images from the camera. The light system can be in different shapes, sizes and brightness. The general light forms are high-frequency fluorescent lamps, LED, incandescent lamps and quartz halide optical fibers. 3. Component sensor It usually appears in the form of grating or sensor. When the sensor senses that the component is close, it will give a trigger signal. When the component is in the correct position, the sensor will tell the machine vision system to collect the image. 4. Image acquisition card Also known as video capture card, this part is usually a card inserted on the PC. The function of this capture card is to connect the camera with the PC. It obtains data (analog signal or digital signal) from the camera and then converts it into information that the PC can process. Industrial machine vision system can also provide signals to control camera parameters (such as trigger, exposure time, shutter speed, etc.). There are many types of image capture cards, Support different types of cameras and different computer buses.

2021

01-06

Linear range and stability of ultrasonic sensor

Linear range: the linear range of the sensor refers to the range in which the output is proportional to the input. In theory, within this range, the sensitivity remains constant. The wider the linear range of the sensor is, the larger its range is, and can ensure a certain measurement accuracy. When selecting the sensor, when the type of sensor is determined, the first thing to see is whether its range meets the requirements. However, in fact, any sensor can not guarantee the linearity, and its linearity is also relative. When the required measurement accuracy is relatively low, within a certain range, the sensor with small nonlinear error can be regarded as linear, which will bring great convenience to the measurement. Stability: The ability of the sensor to keep its performance unchanged after a period of use is called stability. The factors that affect the long-term stability of the sensor are not only the layout of the sensor itself, but also the use environment of the sensor. Therefore, to make the sensor have good stability, the sensor must have strong adaptability to the environment. Before selecting the sensor, its use environment should be investigated, Select appropriate sensors according to the specific use environment, or take appropriate measures to reduce the impact of the environment. The stability of the ultrasonic sensor has quantitative indicators. After the service life, it should be re-calibrated before use to determine whether the performance of the sensor has changed. In some places where the sensor is required to be used for a long time, but cannot be easily replaced or calibrated, the stability of the selected sensor is more strict and can withstand the test for a long time. Frequency response characteristics: the frequency response characteristics of the ultrasonic sensor determine the frequency range to be measured, and must remain undistorted within the allowable frequency range. In fact, the response of the sensor always has a fixed delay. It is hoped that the shorter the delay time is, the better the frequency response of the sensor is, the wider the measurable signal frequency range is. In dynamic measurement, the response characteristics of the signal, such as steady state, transient, random, etc, Avoid excessive errors. Accuracy: It is an important performance index of the sensor, and it is an important link related to the measurement accuracy of the whole measurement system. The higher the accuracy of the ultrasonic sensor, the more expensive its cost is. Therefore, the accuracy of the sensor can meet the accuracy requirements of the whole measurement system as long as it does not have to be too high, so that the relatively cheap and simple sensor accessories can be selected from many sensors that meet the same measurement purpose. If the measurement purpose is qualitative analysis, the sensor with high repetition accuracy can be selected, and the sensor with high measurement accuracy should not be selected; If it is necessary to obtain the measured value for quantitative analysis, it is necessary to select the sensor whose accuracy grade can meet the requirements. For some special places where it is impossible to select the appropriate sensor, it is necessary to design and manufacture the sensor by itself. The performance of the self-made sensor should meet the use requirements.

2021

01-06

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