FAQs on Inductive Sensors

Inductive sensors use electromagnetic induction to measure the distance to metallic objects contactlessly. A current flowing in a coil generates a magnetic field around the coil, which is affected by electrically conductive materials.

Inductive sensors detect objects made of electrically conductive materials such as steel, brass or aluminum.

The digital switching output outputs a signal as soon as an electrically conductive object is detected. The analog output can output the distance proportionally as a voltage value (from 0 V to 10 V) or current value (from 4 mA to 20 mA).

The switching distance is the distance at which a reference target, which is approaching the sensing face of an inductive sensor, triggers a signal change. The standard measuring plate is a 1 mm thick, grounded steel plate where the side length is dependent on the active surface and the nominal switching distance.

The difference between the switch-on and switch-off point as a percentage relative to the switching distance is called switching hysteresis.

The correction factor of an inductive sensor refers to the specified switching distance for an object made of steel. Objects made of different metals are detected by inductive sensors with correction factor 1 at the same switching distance.

When installing inductive sensors, it is important to ensure that a sufficient distance to metallic objects is maintained to avoid unintentional switching of the sensor.

Flush sensors have a metallic ring around the sensor head that protects them from influence from the surrounding material. They are integrated flat or evenly into the surface and are thus protected against damage from passing objects and are ideal for narrow installation situations.

Semi-flush sensors have a slightly larger switching distance compared to flush sensors and have less attack surface for passing objects than non-flush sensors.

With non-flush sensors, the sensing face is not enclosed by a metallic housing. As a result, the magnetic field is not shielded and a larger field can build up.

Inductive sensors detect electrically conductive objects through electromagnetic induction. Object detection in a metallic environment can lead to interference. Photoelectronic sensors detect objects irrespective of the material via infrared light, red light, blue light or laser light. Contamination, vibrations or ambient light can impair object detection by photoelectronic sensors.