Proximity switches (proximity sensors) are widely used in aviation, aerospace technology, and industrial production. In daily life, such as hotels, restaurants, and garages, automatic doors and automatic hot air fans are all used. In terms of security and theft prevention, important places such as data archives, finance and accounting, museums, and vaults are usually equipped with anti-theft devices composed of various proximity switches. In measurement techniques, such as length and position measurement; In control technology, such as displacement, velocity, and acceleration measurement and control, a large number of proximity switches are also used.
1. In environments with good environmental conditions and no dust pollution, photoelectric proximity switches can be used. The photoelectric switch (photoelectric sensor) has almost no impact on the measured object during operation. Therefore, it is widely used in demanding fax machines, printers, tobacco machinery, conveying equipment, automatic doors, and so on.
2. In anti-theft systems, automatic doors typically use photoelectric switches (photoelectric sensors), pyroelectric sensors, and ultrasonic sensors. Sometimes, in order to improve the reliability of recognition, the above-mentioned sensors are often used in combination.
3. In general industrial production sites, inductive (eddy current) proximity switches or capacitive proximity switches are usually used. Because these two types of proximity switches have lower environmental requirements, they can be applied in harsh environments with water, oil, and dust, and require high repeatability accuracy in detection distance. Proximity switches themselves are also widely used in automation equipment.
4. When the tested object is a metal object or an object that can be fixed on a metal object, inductive (eddy current) proximity switches are generally selected because of their high response frequency, good resistance to environmental interference, wide application range, low price, and long service life.
5. If the measured object is non-metal (or metal), liquid level height, powder height, plastic, tobacco, etc. Then choose a capacitive proximity switch. The response frequency of this switch is low and stable. Environmental factors should be considered during installation.
6. If the tested object is a magnetic material or a magnet is buried inside the tested object to distinguish it from objects moving together, a Hall proximity switch should be used. Its price is the lowest, but due to the special nature of the material, it is fragile, and can only detect magnetic metals with low reaction frequency, so its application is limited.
Regardless of the type of proximity switch selected, attention should be paid to the requirements for various indicators such as working voltage, load current, response frequency, detection distance, etc