Yes, the sensing principle in a POSIC encoder is a differential transformer. The primary coil generates a magnetic field, the secondary coils measure the magnetic field, which is modulated by the scale or codewheel. This mechanism works perfectly if the codewheel or scale is not moving.

Yes, the sensing principle in a POSIC encoder is a differential transformer. The primary coil generates a magnetic field, the secondary coils measure the magnetic field, which is modulated by the scale or codewheel. This mechanism works perfectly if the codewheel or scale is not moving.

The POSIC encoder is a differential transformer. The primary coil generates a high-frequency (1 – 2 MHz) magnetic field and measures this field back using the secondary coils. Perturbations below 1 MHz are filtered out. As most magnetic fields from magnets, motors, drives etc are well below 1 MHz, these magnetic fields do not influence the encoder. On above, the secondary coils in the encoder are arranged in a differential was, so that a magnetic field acting on two differential measurement coils is eliminated.