Editorial Feature

What is an Inductive Sensor?

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Inductive sensors are crucial components in machines today. These robust electronic instruments are designed based on the needs of proximity sensor technology, to detect metallic or conductive parts without physical contact or where access is difficult. They can be readily used in outdoor and hygiene-related applications.

There are many inductive sensor designs specifically manufactured to suit a particular application, e.g., high temperature sensors and multi-voltage sensors. Inductive sensors can output appropriate signals for positions and limits as well as act as pulse pick-ups for monitoring rotational speed and counting tasks.

Inductive sensors in a non-contact mode can last a long time as they are not subjected to any mechanical wear and tear. Also, they are resistant to extreme environmental conditions, vibration, dust, and moisture, making them an ideal option for use in several industries.

Working Principle

Inductive sensors comprise an induction loop which is sufficient for electromagnetic detection. They operate by producing an oscillating electromagnetic field created by a moving magnetic object.

The presence of a moving magnetic field triggers flows of current inside the induction loop, in accordance with Faraday’s law of induction. This causes changes in the electromagnetic field, which is detected by the sensor’s circuitry. An appropriate signal is an output when a magnetic metal is detected.

Applications

Inductive sensors are widely used in robotics, military, aerospace, rail, and heavy industrial sectors.

Given below is a list of key inductive sensor applications:

  • Detection of ferrous metals - steel, iron, cobalt, nickel
  • Automotive body assembly
  • Motion position detection and motion control
  • Coil and transformer production
  • Broken bit detection and lid detection
  • Machining processes
  • Tool position and distance measurement
  • Conveyor system control
  • Speed sensing, limit switching, and pulse generation
  • Automated industrial processes
  • Metal detectors
  • For detecting the presence of an object in a pick-and-place application during inspections
  • The production of search coils, used in eye tracking
  • Traffic sensors to detect moving cars
  • Medical: Nuclear Magnetic Resonance coils used in Magnetic Resonance Imaging (MRI)
  • Proximity sensors/switches

Sources and Further Reading

This article was updated on the 30th May, 2019.

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