Want to know how a proximity switch works? The principle and use of the proximity switch

How proximity switches work.

Proximity switchesThe principle and usage method are as follows:

A proximity switch is a position switch that does not require mechanical direct contact with moving parts.

When the object moves the proximity switch sensing surface to the operating distance, the switch can be actuated, thereby driving the load, which can be an intermediate relay.

Or PLC input points.

There are three main categories of proximity switches: inductive proximity switches, capacitive proximity switches, and magnetic proximity switches. Among them, the most commonly used in our work sites are inductive proximity switches.

Inductive proximity switches: The sensing head of an inductive proximity switch is an inductive coil with a ferrite core.

Only metal bodies can be detected. The oscillator generates an alternating magnetic field on the surface of the sensing head, and when a metal object approaches the sensing head, the internal action of the proximity switch is achieved, so as to achieve "on" and "off" control.

Capacitive proximity switch: The sensing head of a capacitive proximity switch is a circular flat electrode that forms a distributed capacitance with the ground wire of the oscillating circuit, which is capacitive when there is a conductor or other medium approaching the sensing head.

The oscillator stops oscillating and outputs an electrical signal through the shaping amplifier. Capacitive proximity sensors can inspect metals, non-metals, and liquids.

Magnetic proximity switch: Magnetic proximity switch mainly refers to Hall proximity switch, and its working principle is Hall effect.

When a magnetic object approaches the Hall switch.

, the state of the Hall proximity switch changes, e.g. from "on" to "off".

1. Inductive proximity switch. The sensing head of an inductive proximity switch is an inductive coil with a ferrite core, which can only detect metal bodies. The oscillator generates an alternating magnetic field on the surface of the sensing head, and when the metal object approaches the sensing head, it approaches the internal action of Kaiqing Yuguan, so as to achieve the control of "on" and "off".

2. Capacitive proximity switch. The inductive head of the capacitive proximity switch is a circular flat electrode, which forms a distributed capacitance with the ground wire of the oscillation circuit, when a conductor or other medium approaches the induction head, the capacitance increases and the oscillator stops oscillating, and the electrical signal is output through the shaping amplifier. Capacitive proximity sensors can be used to inspect metals, non-metals and liquids.

3. Magnetic proximity switch. Magnetic proximity switch mainly refers to Hall proximity switch, its working principle is Hall effect, when the magnetic object is close to the Hall switch, the state of the Hall proximity switch changes, such as from "on" to "off".

Switches can be seen everywhere in our daily life, and the proximity switch is a position switch that can be operated without mechanical direct contact with moving parts, it is also known as a non-contact proximity switch, maybe you will feel very strange when you hear this name, but the proximity switch is widely used in our lives, such as in hotels, restaurants, garages on the automatic door, there are applications of proximity switches, so what is the working principle of the proximity switch?

There is a kind of element in the proximity switch that has the ability to "perceive" the object approaching it, that is, the displacement sensor, which can use the sensitive characteristics of the displacement sensor to the approaching object to achieve the purpose of controlling the switch on or off, and the distance perceived by the displacement sensor after the object moves to the switch and approaches to a certain distance is called the detection distance. Sometimes the detected object is repeated continuously after approaching the switch at a certain time interval and then leaving it one after another, and the response ability of different proximity switches to the detected object is also different chain early, which is called the response frequency.

2. What are the types of proximity switches?

1. Passive proximity switch is a non-contact switch that does not require power supply and is controlled by magnetic induction, which does not require maintenance and is environmentally friendly.

2. Eddy current proximity switch, also known as inductive proximity switch, is the use of conductive objects to produce eddy current inside the object when proximity switching, its anti-interference performance is good, and the switching frequency is high.

3. Capacitive proximity switch is a kind of proximity switch when an object moves to the proximity switch, regardless of whether it is a conductor or not, the dielectric constant of the capacitance can change, it is not limited to the conductor, and the insulating liquid or powder is its detection object.

4. The photoelectric proximity switch, also known as the photoelectric switch, is to install the luminaire and the photoelectric device in the same detection head in a certain direction, and the photoelectric device will output the signal after receiving the reflected light, so that it can perceive that there is an object approaching.

The above is for you to introduce the working principle and types of proximity switches, I hope to help you, understand the working principle and various types of proximity switches, for us to be able to provide a little help when purchasing proximity switches, there are many brands on the market, we should look at all kinds of brands when purchasing, shop around, and choose a good proximity switch through comparison.