Principles of Double-Sheet Detection

Double-sheet detector is a common sensor whose principles are based on two sensing mechanisms, typically electromagnetic induction and the piezoelectric effect.

First, consider electromagnetic induction. When a conductor moves in a magnetic field or the magnetic field intensity changes, an induced electromotive force is generated. Double-sheet detectors use this principle by measuring the induced voltage to detect the presence of material or changes in properties. For example, when a metal object enters the detector's magnetic field, an induced voltage appears and the metal presence can be detected.

The Atonm Metal Double-Sheet Detector is based on electromagnetic principles related to Oersted's discoveries. T is the transmitter and R is the receiver. When an object passes through the diffracted magnetic field generated by T and R, the signal strength returned at R varies with the object's shielding area and thickness, enabling the controller to determine whether a single or multiple sheets entered the sensing range.

Atonm double-sheet detectors are available in through-beam and contact types, developed for different industry needs. They are suitable for automotive, auto components, general metal plate processing, home appliances, batteries, metal packaging, PCB and other industries.

In addition, the piezoelectric effect is another important detection principle. The piezoelectric effect means certain crystals or ceramics generate an electric charge under mechanical stress. Double-sheet detectors exploit this by measuring voltage changes to detect presence or property differences. For example, when a piezoelectric element is pressed, it produces a voltage signal that indicates the presence or characteristics of the object.