High-resolution string encoders give engineers a compact, flexible alternative to LVDTs, optical and rotary encoders, and potentiometers.
An encoder from Space Age Controls, Palmdale, Calif., for example, measures 3.233.233 in., weighs less than 10 oz, and is available with NEMA-4X/IP66 environmental protection. The transducer measures up to 43 in. using a stainless-steel cable that wraps around a threaded aluminum drum. The drum mates to a precision incremental encoder that translates linear position into a digital electrical signal. The devices feature line driver quadrature output with index lines and standard resolutions up to 3,587 pulses/in. (141 pulses/mm). The devices work on 5 to 26 Vdc, in temperatures ranging from -20 to 100C, and for over 100 million cycles.