What is an induction sensor?

Induction sensors are a subset of proximity sensors and are used to detect metal objects in various industries.

The sensor works in such a way that it can detect it without contact with metal objects. Therefore, factors such as friction and mechanical erosion do not affect their lifespan and can work well in environments contaminated with soil, oil, grease, etc. Generally, each induction sensor consists of 4 basic parts.
4 main components of induction sensors

1. Ferrite coil and core

2. Oscillator circuit (oscillator)

3. Detector circuit

4. Output circuit and connector
                                                                                              
                                                                                    The main components of an induction sensor

The oscillator produces a magnetic field that radiates from the ferrite core and the coil. The field is centered around the axis of the ferrite core so that it can be directed to the front of the sensor. When a metal object enters the field and enters, the eddy currents output from the front of the sensor are directed to the surface of the metal object. As a result, the amplifier signal amplitude decreases and the detector circuit detects a change in the oscillator signal amplitude. The detector circuit is activated when the signal amplitude reaches a certain level. When activated, the sensor output is activated.

When the metal object is removed from the magnetic field, the amplitude of the oscillator signal increases. When this amplitude increase reaches a certain level, the output cut command is issued.

The difference between the active and inactive states in the oscillator and detector circuits leads to the hysteresis (H) margin in the operation of the ohmone induction sensor.
                                                                 
Advantages of induction sensor:

The color of the metal body has no effect on its detection.

Lack of impact of polluted environments and dust, etc. on their performance

No friction and mechanical wear

Lack of effect of moisture on its performance

3 important points in choosing the type of proximity sensor (inductive or capacitive)

Induction proximity sensors only detect metal objects.

Strong magnetic fields affect the performance of induction proximity sensors.

The viewing distance of induction proximity sensors is shorter than other sensors.

Difference between single and double induction sensor

When we have limited space to select the sensor diameter, a double sensor can be used.

It can be said that the field of view of a double sensor is equal to a single sensor with a larger diameter instrument.
                                                                            
                                                                        Difference between 12 and 18 diameter sensors with double and single coil
The difference between shielded and unshielded induction sensors
Induction proximity sensors are available in both shielded and non-shielded forms.
                                                                                                   
                                                                                                          Shielded sensors
                                                                                         
                                                                                                        Shielded sensors

In the shielded type, there is a metal ring around the core, which leads to the concentration of the magnetic field just in front of the induction sensor. But in the non-shielded version, there is no metal ring and the magnetic field is not concentrated, but also includes a little around the edge of the sensor. This model of induction sensors is more sensitive than shielded sensors.