Inductive Encoder

An encoder that measures angle or displacement using coils and electromagnetic induction.

An inductive encoder is usually built from transmitter and receiver coils printed on a circuit board, plus a metal target disc that rotates with the shaft. The transmitter coil generates an alternating magnetic field, and as the target disc rotates to different positions, it changes the signal picked up by the receiver coil, from which the angle is computed. It works on a principle similar to a resolver, but packaged as a flat circuit board. Compared with an optical encoder, it isn't bothered by oil, dust, or condensation; compared with a magnet-based magnetic encoder, it's less sensitive to external magnetic interference, and it's easy to build with a large center bore in a ring shape, which suits hollow-shaft joints. The trade-off is somewhat more complex signal processing, with accuracy and cost that fall somewhere between a magnetic encoder and a high-end optical encoder, depending on the specific product.

ExampleThe thin, ring-shaped encoder wrapped around the output shaft in a hollow-shaft joint module may well be an inductive design.

Also called

Induction-Type Encoder

Related

Rotary Encoder · Magnetic Encoder · Optical Encoder · Resolver · Hollow-Shaft Cable Routing

Sources

Zettlex inductive encoders - Celera Motion
Resolver (electrical) - Wikipedia