GAGANMALLIKARJUN .SDUNDAMMAASHWINI

BVB COLLEGE OF ENGINEERING

A Proximity Sensor Detects An Object When The

Object Approaches Within The Detection Range And

Boundary Of The Sensor.

Proximity Sensor Includes All The Sensor That

Perform Non Contact Detection In Comparison To

Sensors Such As Limit Switch ,That Detect The Object

By Physically Contacting Them.

An Inductive proximity sensor is an electronic proximity sensor , which detect metallic object without touching them.

Their operating principle is based on a coil and high frequency oscillator that creates a field in the close surrounding of the sensing surface .

The operating distance of the sensor depends on the coil’s size as well as the target ‘s shape, size and material

The Main Components Of The Inductive ProximitySensor Are. Coil, Oscillator, Detector And The OutputCircuit

The Operating Distance Of The Sensor Depends On TheActuator's Shape And Size And Is Strictly Linked To TheNature Of The Material

The Coil Generates The High Frequency Magnetic FieldIn Front Of The Face. When The Metallic Target Comes InThis Magnetic Field It Absorbs Some Of The Energy

Magnetic field

•The coil shown in below construction inductoris wound around a ferrite core.

• An electromagnetic field continuously expands and cantracts around the coil.

• The shape of the core cases the flux lines to bundletogether

• unshielded sensor. Which directs the flux lines to the front and side of the sensor head

• a shielded sensor with a shielded metal band around the ferreite core

Sensor head

• consists of a closed loop op-amp configuration• has a tank circuit connected to the non iverting input head• one brach of the tank contains a capacitor and the other branch an inducter• once power appled,resonance develops in the tank and the oscllators will produce a frequency between 100Hz to 1Hz.• oscillating sinal as fed into demodulator section• filtered rectifier whch converts the AC singnal into a DCvoltage level

Oscillator and Demodulator

• Output of the demodulator connected to aSchmitt trigger input.

• produces two voltages.• If demodulator decreases to certain amplititude, it causes the trigger output to quickly change to a low voltage level.

Trigger stage / Evaluation Unit

• The function of the output stage is to drive a load ON or OFF. It’s consists of an NPN current snking transistor or a PNP current sourcing device.

Output stage

Application 1: Determination of position with the use of two inductive sensors.

Application 2: Interrogation of a camshaft gear with inductive sensors

Wind power plantApplication 3

Use to detect metal. Use magnetic field for detection. Consist of 4 part of constructon. Only detect ferrous metal. Many use in industries. Can detect metal that have dirt on it.