Proximity sensors & switches are divided into inductive proximity sensor, capacitive proximity sensor, magnetic proximity sensor, analog proximity sensor and Hall proximity sensor. Proximity sensor can support using with PLC, SCM, Sr circuit, Electronic counter, solid state relay, miniature relay and other products. In an automatic control system, proximity sensor can be used as a device for the limit, count, positioning control and automatic protection.
Proximity sensor has a small size, cheap price, fast frequency response, wide voltage range, anti-interference ability, long life, low power consumption, no mechanical wear, no sparks, no noise, corrosion resistance, vibration resistance and other characteristics. So proximity sensor can be used in poor work environments.
The inductive proximity sensor consists of a high-frequency oscillation circuit, a detection circuit, an amplifying circuit, a shaping circuit and an output circuit. The sensing element used for detection is the detection coil, which is an integral part of the oscillating circuit.
Capacitive sensors are constructed from many different media, such as copper, indium tin oxide (ITO), and printing inks. Copper capacitive sensors can be implemented on standard FR4 PCBs as well as flexible materials. ITO allows up to 90% transparency for capacitive sensors (for one-layer solutions such as touch phone screens).
Hall magnetic proximity sensor is a non-contact position detection switch with the function of converting a magnetic quantity signal into an electrical signal. ATO magnetic proximity sensors are at a low price, providing M8, M12, and M18 thread sizes for you to choose from, NPN/ PNP, and NO/ NC signal output, which are mainly used for special-purpose machinery, automatic controls, packaging and conveyor systems.
The polarity of the proximity sensor has two types, PNP and NPN. The principle of PNP and NPN sensors is to use the saturation and cut-off of triodes to output two states, which belong to switch sensors, but the output signals are diametrically opposite. high level and low level. NPN output is low level 0, and PNP output is a high level 1. The following video shows you how to change the PNP (NPN) type proximity sensor to the NPN (PNP) type.