Draw-Wire Sensors

Draw-wire sensors measure long linear travel by attaching a retractable measuring cable to the moving part. Inside the housing sits the transducer mechanism (potentiometer or rotary encoder) that converts the reel-out into a position signal.

Compact plastic housings with potentiometer output cover strokes up to 5 meters. They are used cost-effectively in stage equipment, test benches, and model-making.

Rugged metal housings with SSI, CANopen, or analog interfaces reach 20 to 50 meters. They provide position feedback on hydraulic cylinders in mobile hydraulics, aerial work platforms, scissor lifts, and telescopic booms of cranes.

Stainless-steel versions rated IP67/IP69K qualify for marine, offshore, and wash-down applications.

Compared with magnetostrictive or optical position sensors of similar stroke, draw-wire sensors cost noticeably less and are easier to retrofit, but they carry mechanical wear.