hybrid incr/absolute encoders • add more information to index channel to reduce amount of seeking required to find reference position. • interface requires lots of wires (parallel) or a special comm. protocol
Magnetostrictive Pos. Sensor • Pulse sent down magnetostrictive material • Pulse reflects off position magnet’s field • Position is proportional to trcvd - tsent • Pulse propagates at ~2800 m/s • Resolution is ~.001” with tupdate ~1msec/in.