Drives and Controls Magazine

Encoder modules offer wear-free alternative to pots

19 August, 2009

Renishaw has announced a new generation of solid-state, non-contact magnetic encoders that offer a more reliable alternative to traditional potentiometer feedback devices. The modules provide the same rising voltage output signal and use the same wiring as traditional potentiometers, but are not affected by contamination and offer an almost unlimited, wear-free life.

The digital potentiometers are said to provide the ease of use of traditional wirewound pots, but without the limitations such as the degradation in performance – or even failure – that can be caused by wear and contamination. Although traditional potentiometers provide a low-cost form of analogue position feedback that is simple to integrate, if they get dirty or worn they can become unreliable and noisy, eventually requiring replacement.

The new magnetic encoder modules, developed in association with Renishaw’s associate company RLS, provide a linear output voltage, proportional to the rotation angle, like a potentiometer, but without making physical contact.

The digital encoders are impervious to contamination by dirt, grease, oils, and dust, and are not affected by shock and vibration. There are no wipers, seals, bearings or other moving parts to wear or become contaminated.

The solid-state encoders can be sealed to IP68 for outdoor or submerged operation.