How to Wire The Magnetic Proximity Switch, Principle and Characteristics? What is the working principle and characteristics?

The magnetic proximity switch is a kind of proximity switch. The magnetic proximity switch is one of many types in the sensor family. It is made of electromagnetic working principle and advanced technology. It is a position sensor. It can convert the non-electric or electromagnetic quantity into the desired electrical signal through the change of the positional relationship between the sensor and the object, so as to achieve the purpose of control or measurement. This article collects and sorts out some information, hoping to be of great reference value to readers.

Magnetic Proximity Switch, Principle and Characteristics

Magnetic Proximity Switch, Principle and Characteristics

How Magnetic Proximity Switches Work

Magnetic proximity switches can achieve the largest detection distance with a small switch volume. It can detect magnetic objects (usually permanent magnets), and then generate a trigger switch signal output. Since the magnetic field can pass through many non-magnetic objects, the triggering process does not necessarily require the target object to be directly close to the sensing surface of the magnetic proximity switch, but to transmit the magnetic field to a long distance through a magnetic conductor (such as iron), for example, the signal can pass through The high temperature is transmitted to the magnetic proximity switch to generate a trigger action signal.

Its working principle is similar to that of an inductive proximity switch. It contains an LC oscillator, a signal trigger and a switching amplifier inside, as well as an amorphous, high-transmittance magnetic soft glass metal core. The core causes eddy current loss to attenuate the oscillating circuit. If it is placed within a magnetic field (for example, near a permanent magnet), the eddy current loss that is affecting the attenuation of the oscillating circuit will decrease, and the oscillating circuit will no longer attenuate. Therefore, the power consumption of the magnetic proximity switch increases due to the proximity of the permanent magnet, and the signal trigger is activated to generate an output signal. It has a wide range of applications, such as: objects can be detected through plastic containers or conduits; object detection in high-temperature environments; material identification systems; code identification with magnets, etc.

How to wire the magnetic proximity switch?

1. Introduction to the symbols of magnetic proximity switches:

Black (BK): The output line indicated as normally open output.

White (WH): indicates the output line of normally closed output.

Brown (BN): indicates the power cord connected to the positive pole of the power supply.

Blue (BU): Indicates the power cord connected to the negative pole of the power supply.

PNP: Indicates that the load wiring is black, and the negative pole of the power supply is the load at the other end.

NPN: Indicates that the load wiring is black, and the positive pole of the power supply is the load at the other end.

2. The wiring method of magnetic proximity switch is divided into two-wire system and three-wire system:

(1) The two-wire proximity switch has a relatively simple wiring method, that is, it is directly connected to the power supply after being connected in series with the load.

(2) However, there are two different wiring methods for the three-wire proximity switch, namely NPN type and PNP type:

The same thing between the two different wiring methods is that the brown wire is connected to the positive end of the power supply, the load should be connected to the black wire, and the OV end of the power supply should be connected to the blue wire. The difference between the two methods is that the NPN type is connected to the positive end of the power supply at the other end of the load, and the PNP type is connected to the OV end of the power supply.

The three-wire proximity switch is more reliable in actual work, because the three-wire proximity switch is not easily affected by the residual current, while the two-wire proximity switch will have a voltage drop when it is turned on, and there will be a residual current. It should be considered Choose from specific work situations.

Advantages and disadvantages of magnetic proximity switches

1. Advantages of magnetic proximity switches:

(1) Can be installed in metal as a whole.

(2) There is no requirement for side-by-side installation.

(3) The head (sensing surface) may be made of metal.

(4) Low price and simple structure.

(5) It has a large sensing range and high switching frequency.

2. Disadvantages of magnetic proximity switches:

(1) The operating distance is greatly affected by the magnetic field strength of the detection object (usually a magnet or a magnetic steel).

(2) The approach direction of the detection body will affect the size of the action distance (radial approach is half of the action distance when approaching in the axial direction).

(3) There may be two operating points when radially approaching.

(4) It is not allowed to use ferrite or screws when fixing the test body, only non-ferrous materials can be used.

This article can only lead you to have a preliminary understanding of the magnetic proximity switch. I hope it will be helpful to you. At the same time, it needs to be continuously summarized so as to improve professional skills. You are also welcome to discuss some knowledge points of the article.

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