Difference between two-wire proximity switch and three-wire proximity switch - 推酷

Probe domestic switch needle KG-300K needle head diameter is 3.0mm normally open switch needle

Murata muRata winding inductance original authentic assured purchase

For the two-line proximity switch, it is equivalent to a switch, and can sense the proximity of metal or non-metal. The general principle is Hall effect. The three lines are equivalent to two outputs, one is normally closed and the other is normally open. When something is close, the state will change. Generally, we only use one end. For the latter stage, the differential amplifier is usually used to improve the waveform to make it a step wave. The voltage drop of the two lines It is much larger than the three wires, so pay attention to the minimum opening voltage of the load when using it. The two-wire switch must pass the load (signal light, relay coil or digital input module of programmable controller plc), otherwise the switch will Short circuit burned out. Inside the proximity switch is a magneto-sensitive resistor. When it approaches the resistance of the metal resistor, it becomes smaller. The loop that turns on the two-wire must be connected to the power supply after it has to carry the load of the current. It is absolutely not allowed to connect to the power supply without a load. .
Three-wire two-wire power supply, one-line output, divided into NPN type and PNP type, NPN type output low level, PNP type output high level. My factory has two-wire system, three-wire switch, and four-wire switch. The four-wire switch enters the DI card of the Siemens plc as an input point and participates in the logic. The three-wire proximity switch requires power support and the output is an active signal. In fact, in general, there is a metal induction head plus internal circuit, and those triodes are used to amplify and output high and low levels (NPN tube low level; PNP tube, high level). Therefore, people often say that it is NPN type or PNP type. The proximity switch is a contactless sensor switch and is an ideal electronic switch sensor.
When the metal detector is close to the sensing area of ​​the switch, it can be contactless, without pressure, without spark, and quickly emit electrical commands, accurately reflecting the position and stroke of the moving mechanism, even for general stroke control, its positioning accuracy, operating frequency, The service life, ease of installation adjustment, and ability to withstand harsh environments are not comparable to conventional mechanical travel switches.
The inside of the two-wire proximity switch is a sense diode, and the interior of the three-wire proximity switch is an induction triode.
The two-wire proximity switch has the disadvantage of large residual voltage and large leakage current. The three-wire proximity switch is divided into NPN and PNP, and is widely used. I have used two kinds of proximity switches: the three wires are connected to the DC24V power supply, and the other is the signal cable. The second line is connected to the DC24V power supply and the other is the signal line. As for whether the interior is said to be a sense diode or a triode upstairs, it is not clear. The two-wire loop must be connected to the power supply after it has been allowed to carry the current load. It is absolutely not allowed to connect to the power supply without a load.
Three-wire two-wire power supply, one-line output, divided into NPN type and PNP type, NPN type output low level, PNP type output high level. For the two-line proximity switch, it is equivalent to a switch, and can sense the proximity of metal or non-metal. The general principle is Hall effect. The three lines are equivalent to two outputs, one is normally closed and the other is normally open. When something is close, the state will change. Generally, we only use one end.
The two-wire loop must be connected to the power supply after it has been allowed to carry the current load. It is absolutely not allowed to connect to the power supply without a load.
Three-wire two-wire power supply, one-line output, divided into NPN type and PNP type, NPN type output low level, PNP type output high level is generally convenient for 2-wire system proximity switch wiring, and NPN is used when wiring with three-wire system. PNP is two, and the leakage current of the three-wire proximity switch is small, but the price of the three-wire proximity switch is generally relatively expensive. The three lines are equivalent to two outputs, one is normally closed and the other is normally open. When something is close, the state will change. We only use one end to make the second line of the circuit must have it to allow the current load. Only when it is connected to the power supply, it is absolutely not allowed to connect to the power supply without a load. For the two-line proximity switch, it is equivalent to a switch, and can sense the proximity of metal or non-metal. The general principle is Hall effect. The three lines are equivalent to two outputs, one is normally closed and the other is normally open. When something is close, the state will change. Generally, we only use one end. For the latter stage, the differential amplifier is usually used to improve the waveform to make it a step wave. The voltage drop of the two lines It is much larger than the three lines, so pay attention to the minimum opening voltage of the load when using it. The two-wire switch must pass the load (signal light, relay coil or PLC digital input module), otherwise the switch will Short circuit burned out. Inside the proximity switch is a magneto-sensitive resistor. When it approaches the resistance of the metal resistor, it becomes smaller. The loop that turns on the two-wire must be connected to the power supply after it has to carry the load of the current. It is absolutely not allowed to connect to the power supply without a load. .
Three-wire two-wire power supply, one-line output, divided into NPN type and PNP type, NPN type output low level, PNP type output high level. My factory has two-wire system, three-wire switch, and four-wire switch. The four-wire switch enters the DI card of the Siemens PLC as an input point and participates in the logic. The three-wire proximity switch requires power support and the output is an active signal. In fact, in general, there is a metal induction head plus internal circuit, and those triodes are used to amplify and output high and low levels (NPN tube low level; PNP tube, high level). Therefore, people often say that it is NPN type or PNP type. The proximity switch is a contactless sensor switch and is an ideal electronic switch sensor.
When the metal detector is close to the sensing area of ​​the switch, it can be contactless, without pressure, without spark, and quickly emit electrical commands, accurately reflecting the position and stroke of the moving mechanism, even for general stroke control, its positioning accuracy, operating frequency, The service life, ease of installation adjustment, and ability to withstand harsh environments are not comparable to conventional mechanical travel switches.
The inside of the two-wire proximity switch is a sense diode, and the interior of the three-wire proximity switch is an induction triode.
The two-wire proximity switch has the disadvantage of large residual voltage and large leakage current. The three-wire proximity switch is divided into NPN and PNP, and is widely used. I have used two kinds of proximity switches: the three wires are connected to the DC24V power supply, and the other is the signal cable. The second line is connected to the DC24V power supply and the other is the signal line. As for whether the interior is said to be a sense diode or a triode upstairs, it is not clear. The two-wire loop must be connected to the power supply after it has been allowed to carry the current load. It is absolutely not allowed to connect to the power supply without a load.
Three-wire two-wire power supply, one-line output, divided into NPN type and PNP type, NPN type output low level, PNP type output high level. For the two-line proximity switch, it is equivalent to a switch, and can sense the proximity of metal or non-metal. The general principle is Hall effect. The three lines are equivalent to two outputs, one is normally closed and the other is normally open. When something is close, the state will change. Generally, we only use one end.
The two-wire loop must be connected to the power supply after it has been allowed to carry the current load. It is absolutely not allowed to connect to the power supply without a load.
Three-wire two-wire power supply, one-line output, divided into NPN type and PNP type, NPN type output low level, PNP type output high level is generally convenient for 2-wire system proximity switch wiring, and NPN is used when wiring with three-wire system. PNP is two, and the leakage current of the three-wire proximity switch is small, but the price of the three-wire proximity switch is generally relatively expensive. The three lines are equivalent to two outputs, one is normally closed and the other is normally open. When something is close, the state will change. We only use one end to make the second line of the circuit must have it to allow the current load. Only when it is connected to the power supply, it is absolutely not allowed to connect to the power supply without a load.