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News

06

2023

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01

Precautions for use of proximity switch

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【概要描述】The proximity switch, also known as contactless proximity switch, is an ideal electronic switch sensor. When the metal detector approaches the sensing area of the switch, the switch can send out electrical instructions without contact, pressure and spark, and accurately reflect the position and travel of the moving mechanism. That is, it is used for general travel control. Its positioning accuracy, operating frequency, service life, convenience of installation and adjustment, and adaptability to harsh environment, It is incomparable with general mechanical travel switch. It is widely used in machine tool, metallurgy, chemical industry, light textile, printing and other industries. It can be used as limit, count, positioning control and automatic protection link in automatic control system. In general industrial production sites, eddy current proximity switches and capacitive proximity switches are usually selected because of the low environmental requirements of these two proximity switches. When the measured object is a conductive object or an object that can be fixed on a metal object, eddy current proximity switches are generally selected because of its high response frequency, good environmental interference resistance, wide application range and low price. If the measured object is non-metal (or metal), liquid level height, powder height, plastic, tobacco, etc., the capacitive proximity switch should be selected. The response frequency of this switch is low, but the stability is good. The impact of environmental factors should be considered during installation. If the measured object is magnetic material or magnetic steel is buried in the measured object in order to distinguish the object moving with it, the Hall proximity switch should be selected. Its price is low. Photoelectric proximity switches can be used in places with good environmental conditions and no dust pollution. When the photoelectric proximity switch works, it has almost no impact on the tested object. Therefore, it is widely used in fax machines with high requirements and tobacco machinery. In the anti-theft system, pyroelectric proximity switch, ultrasonic proximity switch and microwave proximity switch are usually used for automatic doors. Sometimes, in order to improve the reliability of identification, the above proximity switches are often used in combination. Regardless of which proximity switch is selected, attention should be paid to the requirements for working voltage, load current, response frequency, detection distance and other indicators.

The proximity switch, also known as contactless proximity switch, is an ideal electronic switch sensor. When the metal detector approaches the sensing area of the switch, the switch can send out electrical instructions without contact, pressure and spark, and accurately reflect the position and travel of the moving mechanism. That is, it is used for general travel control. Its positioning accuracy, operating frequency, service life, convenience of installation and adjustment, and adaptability to harsh environment, It is incomparable with general mechanical travel switch. It is widely used in machine tool, metallurgy, chemical industry, light textile, printing and other industries. It can be used as limit, count, positioning control and automatic protection link in automatic control system.
In general industrial production sites, eddy current proximity switches and capacitive proximity switches are usually selected because of the low environmental requirements of these two proximity switches. When the measured object is a conductive object or an object that can be fixed on a metal object, eddy current proximity switches are generally selected because of its high response frequency, good environmental interference resistance, wide application range and low price.
If the measured object is non-metal (or metal), liquid level height, powder height, plastic, tobacco, etc., the capacitive proximity switch should be selected. The response frequency of this switch is low, but the stability is good. The impact of environmental factors should be considered during installation. If the measured object is magnetic material or magnetic steel is buried in the measured object in order to distinguish the object moving with it, the Hall proximity switch should be selected. Its price is low.
Photoelectric proximity switches can be used in places with good environmental conditions and no dust pollution. When the photoelectric proximity switch works, it has almost no impact on the tested object. Therefore, it is widely used in fax machines with high requirements and tobacco machinery.
In the anti-theft system, pyroelectric proximity switch, ultrasonic proximity switch and microwave proximity switch are usually used for automatic doors. Sometimes, in order to improve the reliability of identification, the above proximity switches are often used in combination. Regardless of which proximity switch is selected, attention should be paid to the requirements for working voltage, load current, response frequency, detection distance and other indicators.


BARTEC explosion-proof switch-Germany BARTEC limit type micro switch/travel switch

BARTEC explosion-proof switches are special-purpose switches developed by the renowned German company BARTEC, which was founded in 1975 in Baden-Württemberg.

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Comparison between optical fiber sensor and traditional sensor

At present, in the Chinese market, fiber Bragg grating (equipped with ASE broadband light source) and distributed sensor based on optical time-domain reflection are the most widely used optical fiber sensing technologies. This technology can basically meet the needs of the medium and low end general market and is well known by industry insiders. The single-frequency fiber laser with spectral linewidth as narrow as 2 kHz and the latest generation of optical sensing technology introduced now are completely different from the optical fiber sensing we now know. This new technical solution can fully meet the higher demand for ultra-long distance, ultra-high precision and ultra-high sensitivity in the high-end market, which cannot be completed by electric sensing and general optical fiber sensing. However, this technology is still in the stage of project approval and pre-research in China. Compared with traditional sensing technology, fiber-based sensors have the following major advantages: 1. Light weight, compact structure, easy to reuse in multiple ways; 2. Resistance to harsh environment, electromagnetic interference and chemical corrosion; 3. There is no need for electricity at the sensing point, and long-distance distributed sensing is possible; 4. Low cost mass production After optical fiber communication, optical fiber sensing has also ushered in an important development opportunity. It has extensive and huge application value in security, military, oil/gas, electricity and scientific research, especially in western developed countries. The optical principle of single-frequency fiber laser for optical sensing is optical frequency time-domain reflection.

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Structure principle and classification of optical fiber sensor

1. Structure principle of optical fiber sensor The traditional sensor based on electricity is a device that converts the measured state into measurable electrical signals. Its power supply, sensitive components, signal receiving and processing system and information transmission are all connected with metal wires. Optical fiber sensor is a device that converts the measured state into a measurable optical signal. It is composed of optical transmitter, sensing element (optical fiber or non-optical fiber), optical receiver, signal processing system and optical fiber. The light emitted by the optical transmitter is guided to the sensitive element through the source optical fiber. At this time, a certain property of the light is modulated by the measured, and the modulated light is coupled to the optical receiver through the receiving fiber, so that the optical signal is converted into an electrical signal, and finally the desired measured signal is obtained through signal processing. It can be seen that the optical fiber sensor is essentially different from the traditional sensor based on electricity in measuring principle. Traditional sensors are based on mechanical-electrical measurement, while optical fiber sensors are based on optical measurement. Light is a kind of electromagnetic wave, whose wavelength ranges from 1 mm in the far infrared to 10 nm in the far ultraviolet. Its physical and biochemical effects are mainly caused by the electric field. Therefore, when discussing the sensitive measurement of light, we must consider the vibration of the electric vector E of light, namely A - amplitude vector of electric field E; ω—— Vibration frequency of light wave; φ—— Optical phase; T - propagation time of light. It can be seen that as long as one of the parameters such as the intensity, polarization state (direction of vector A), frequency and phase of the light changes with the change of the measured state, or is modulated by the measured state, then the required measured information can be obtained by adjusting the intensity modulation, polarization modulation, frequency modulation or phase modulation of the light. 2. Classification of optical fiber sensors Note: MM multimode; SM single mode; PM polarization maintenance; a. B, c functional type, non-functional type, pickup type

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The exhibition of the first Fuji Electric Import Expo ended smoothly

The China International Import Expo is a major measure taken by the Chinese government to firmly support trade liberalization and economic globalization and actively open its market to the world. The exhibition covers seven major industries, including service trade, automobile, high intelligent high-end equipment, consumer electrical machinery and equipment. Fuji Electric Co., Ltd. also participated in the exhibition. With the theme of energy and environment business, in the 108 square meters, blue and white Fuji Electric Exhibition Hall, energy optimization and stabilization were carried out; Achieve stable operation and energy-saving effect of the plant; Environmental measurement of air pollution, etc., to the optimal operation of equipment; It also saves labor and people, and provides four displays of food safety and reassurance.

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琦威(香港)有限公司

Kiwell (Hongkong) Co., Ltd.

Add:  Workshop Unit No. A6, 8/F, Hoplite Industrial Centre, No. 3 & 5 Wang Tai Road, Kowloon Bay, Kowloon, Hongkong

Tel:852 3171 1488  

Fax:852 3111 6959

佛山市琦威电气技术有限公司

Kiwell (Foshan) Electric Technology Co., Ltd.

Add :  Floor 3,Block 5,No.23,Xinghua Road,

           Zhangcha Street,Foshan Clty,Guangdong Province

Tel :   0757-83276620    13827717320 

Fax :  0757-83992196

Mailbox: info@kiwell.cn

 

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