Magnetic Switch Function How are magnetic switches wired

Magnetic switch function

Magnetic proximity switch is a kind of proximity switch. Proximity switch is one of many types in the sensor family. It is made by using electromagnetic working principle and advanced technology. It is a position sensor. It can transform the non-electricity or electromagnetic quantity into the desired electric signal through the change of the positional relationship between the sensor and the object, so as to achieve the purpose of control or measurement.

The magnetic proximity switch can reach the maximum detection distance with a small switch volume. It can detect magnetic objects (usually permanent magnets), and then generate trigger switch signal output. Since the magnetic field can pass many non-magnetic objects, this triggering process does not necessarily require the target object to be directly approached 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 The high temperature is transmitted to the magnetic proximity switch to generate the trigger action number.

Magnetic proximity switches are widely used in aviation, aerospace technology and industrial production. In daily life, such as hotels, restaurants, garages, automatic doors, automatic hot air blowers have applications. In terms of security and anti-theft, such important places as data archives, accounting, finance, museums, and vaults are usually equipped with anti-theft devices composed of various proximity switches. In measurement technology, such as length and position measurement; in control technology, such as displacement, velocity, acceleration measurement and control, a large number of proximity switches are also used.

How to wire the magnetic switch

bk (black) black: generally the output line, the output is normally open.

bn (brown) brown: Generally, it is a power cord, connected to the positive pole of the power supply.

bu (blue) blue: generally the power cord, connected to the negative pole of the power supply.

wh (white) white: generally the output line, the output is normally closed.

npn: The black end is connected to the load, and the other end of the load is connected to the positive terminal of the power supply.

pnp: The black end is connected to the load, and the other end of the load is connected to the negative pole of the power supply.

1. The proximity switch has the difference between two-wire system and three-wire system. Three-wire proximity switches are divided into NPN type and PNP type, and their wiring is different.

2. The wiring of the two-wire proximity switch is relatively simple. The proximity switch is connected in series with the load and then connected to the power supply.

3. Wiring of the three-wire proximity switch: the red (brown) wire is connected to the positive terminal of the power supply; the blue wire is connected to the 0V terminal of the power supply; the yellow (black) wire is the signal and should be connected to the load. The other end of the load is connected like this: For NPN proximity switches, it should be connected to the positive end of the power supply; for PNP proximity switches, it should be connected to the 0V end of the power supply.

4. The load of the proximity switch can be a signal lamp, a relay coil or a digital input module of a programmable controller PLC.

5. Special attention should be paid to the type selection of the three-wire proximity switch connected to the PLC digital input module. PLC digital input modules can generally be divided into two categories: one type of public input terminal is the power supply 0V, current flows from the input module (Japanese mode), at this time, the NPN type proximity switch must be selected; the other type of public input terminal It is the positive terminal of the power supply, and the current flows into the input module, that is, the well input (European mode). At this time, the PNP proximity switch must be selected. Never choose the wrong one.

6. The two-wire proximity switch is limited by the working conditions. When it is turned on, the switch itself produces a certain voltage drop, and when it is turned off, there is a certain amount of residual current flowing. It should be considered when selecting. Although the three-wire proximity switch has one more wire, it is not troubled by unfavorable factors such as residual current and works more reliably. 7. Some manufacturers lead the "normally open" and "normally closed" signals of the proximity switch at the same time, or add other functions. In this case, please follow the product manual for specific wiring.