INDUCTIVE PROXIMITY SWITCHES
The mode of action of inductive sensors is based on a magnetic field generated by a coil (winding). When an electrically conductive material comes near the sensor, eddy currents are generated in the magnetic field. An oscillator detects the change in the magnetic field, and the sensor switches. This simple sensor principle can be used to detect positions in a non-contact, and thus wear-free, manner.
Inductive proximity switches have high switching accuracy (0.1 mm (0.0039 inches)), and can be used up to 80 °C (176 °F) (in special cases up to 120 °C (248 °F)). This means that they are ideal position sensors for hydraulic cylinders. They can be integrated into hydraulic cylinders in a pressure-tight manner, and are used for end position sensing.
If a cylinder with a high pressure inductive sensor is selected, the sensing point can be defined up to 5 mm (0.2 inches) before the stroke end position. Subsequent relocation of sensing point is not possible.
A special option for cylinders with inductive proximity switches is the fitting of an external sensor; this is implemented by means of an actuating rod opposite the piston rod. This allows easy adjustment of the sensing points
If the ripple in the electronic system is too high, malfunctions may occur in inductive sensors.