05 May 2022
Difference between ferrous and non-ferrous products
- Ferrous products: any steel
- Non-ferrous products: any metal except steel (brass, copper, etc.)
- non-ferrous does not mean any material (wood, plastic, etc.)
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 products vary according to the metals to be detected: maximum for ferrous and dependent on a Km coefficient typical of each metal (value between 0 and 1: Km = 1 for steel). This coefficient reduces the sensor detection range. For example if Km = 1 for cast iron, it is only 0.25 for copper. This is the conventional inductive sensor.
Both for ferrous (steel, iron) and non-ferrous (brass, aluminium, 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. The Schneider part numbers are: XS1M18KPM40x, XS1M30KPM40x 18mm and 30mm diameter sensors respectively, and also XS7C40KPM40.
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 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