Maxon motor released its MILE inductive micro encoder with a configurable index pulse and integrated commutation signals.
Secure against the effects of EMC, dust, or oil, it measures 6 mm in diameter, delivers 64 pulses at up to 120,000 rpm, has 3 channels, a line driver, and integrated commutation outputs.
According to the company, the general basis of inductive encoders is that the inductance of one or more coils changes in relation to the material used; a semi-circular iron core representing the material measure could be directed to a coil which then changes its inductance.
However, there are drawbacks to simple inductive encoders, such as the temperature dependence of the soft iron/ferrite.
External magnetic fields can also change the permeability of the material used, well below saturation point. With the MILE encoder, the contrast is generated with eddy currents.