Proximity sensors are capable of detecting nearby objects without physical contact, and that is why they are also referred to as non-contact sensors. Proximity sensors work by releasing the electromagnetic field or radiation. This results in changes in the field which tries to return the produced signal. The proximity sensors target refers to the object which is being sensed. Most proximity sensors have a longer functional life. They are quite reliable because of the minimal mechanical parts as well as lack of physical contact between the target and the sensor. Most of the sensors have a wide operating temperature range of between -40oC to 200oC and cannot be affected by the color of the object. There are different types of proximity sensors as highlighted below.
Inductive Proximity Sensor –This sensor derives its name from its functioning principle of detecting under electric inductance and is used for detecting metallic objects. It has an oscillator circuit that it uses to generate the electromagnetic field of high frequency. The sensor contains an inductive loop, and when the cable is out of the sensor, it turns red, and a metal target is detected. Once the cable is removed, the output of the sensor is switched off. Check out this website at https://www.youtube.com/watch?v=npD48agt0xY for more info about sensors.
Capacitive Sensor-Capacitive sensor at https://magnasphere.com/technology/industrial-commercial-issues/ferrous-proximity-sensor is intended for the detection of both metallic and non-metallic objects, which could be in liquid, solid as well as granulated form. This sensor functions as an open capacitor since it has two conduction plates which are placed at the sensing head. The capacitance of these plates increases whenever an object enters the sensing area, and this causes a change in the oscillator amplitude. The capacitive sensor is meant to oscillate whenever the target is present. The charging plates usually have a frequency ranging from 10 to 50HZ. This capacitive proximity sensor is designed to detect any material and to avoid undesirable triggers from the sensor; it should be kept away from non-target material.
Photoelectric Sensor- This sensor from this link can detect an object that is within 1mm diameter and is more advanced. The photoelectric sensor has the potential to solve various industrial sensing issues. These proximity sensors are made with a laser diode, and a photodiode receiver meant for the detection of emitted light. They come with supporting electronics that are designed for the amplification of the receiver. A receiver emitter is used since it can transmit the beam of infrared or visible light. Get your proximity sensor from a reputable dealer.
