Principle of Operation
Measurement is based on coil impedance detection. A magnet and an electromagnet inside the detector vibrate the plate. Current that flows on the electromagnet decreases when the detector is covered by the measured material. The sensor detects this change to detect solid presence and gives an output.
When the detector is not covered by the material
The electromagnet vibrates at its operating frequency when alternating current is applied.
Back electromotive force on the electromagnet becomes the largest due to change in magnetic field from the magnet
The sensor determines the detector is not covered by the material.
When the detector is covered by the material
Applying alternating current does not cause the electromagnet to vibrate at its operating frequency.
No back electromotive force occurs because the magnet is stationary.
The sensor determines the detector is covered by the material.