Please note - As of 01/09/23 the Telemecanique Sensors range is no longer part of Schneider Electric. This FAQ is now for reference only. For further information and contact details for Telemecanique Sensors, please visit their website; https://www.telemecaniquesensors.com/global/en.

Difference between ferrous product to be detected and non-ferrous product to be detected

Ferrous products:  any steel
Non-ferrous products: any metal except steel (brass, copper, etc.)

• Caution, non-ferrous does not mean any material (wood, plastic, etc.), it refers to metals

Difference between ferrous sensors and non-ferrous sensors

There are sensors which can detect:

Ferrous metals as a preference (steel, iron)
The sensing distances for these sensors would vary according to the metals to be detected. Please contact manufacturer for material coefficient.

The maximum coefficient for ferrous metals (dependent on a Km coefficient typical of each metal) is 1. See table below.
This coefficient reduces the sensor detection range. For example while Km = 1 for cast iron, it is only 0.25 for copper.
This is the conventional inductive sensor

Both ferrous (steel, iron) and non-ferrous (brass, aluminum, copper, etc.) metals
The sensing distance for these sensors is the same for both ferrous and non-ferrous materials. The Km coefficient is always 1
They are called Ferrous/Non-Ferrous sensors.

Selective, either ferrous materials or non-ferrous materials
They are called selective Ferrous/Non-Ferrous sensors.

Difference in detection principles
For both sensors, an LC oscillator creates an electromagnetic signal.

The difference in detection principles for the two types of sensor lies in:

Attenuation of the oscillation amplitude for ferrous materials, it is significant for ferrous materials and insignificant for non-ferrous materials
Variation in oscillation frequency for selective or non-selective ferrous/non-ferrous materials. For high-frequency operation (in the region of one MHz), both types of material (ferrous and non-ferrous) have the same effect on the oscillation frequency variation.
Km coefficient depending on the different metals for inductive sensors

Released for:Schneider Electric Ireland