Angular encoder operates in harsh environments

Paul Boughton
Zettlex is launching a high-precision angle encoder that uses an innovative absolute inductive measuring technique. The measurement performance of the device is claimed to be unaffected by humidity, moisture, condensation or dust and is therefore suitable for use in harsh environments where electrical contacts, optical encoders or capacitive devices may be unreliable. Known as the Incoder, this device is a non-contact, high-precision absolute angle encoder that has a stator and a rotor, each in the form of a flat ring. The large bore makes it easy to accommodate large through-shafts, slip rings or cables, for example.
According to Zettlex, the Incoder is suitable for a variety of applications, including: test and calibration equipment; rotary joints and gimbals; camera mounts; actuator servos and motor encoders; radar systems; light and heavy-calibre weapons systems; antenna-pointing devices and range finders; robotic arms and CNC machine tools; packaging machinery; and laboratory automation.
Mark Howard, general manager at Zettlex, comments: "The Incoder has an unusual shape and so immediately grabs the attention of design engineers. The device was purposefully designed to be flat with a low profile - so it makes life easier for design engineers when they are struggling with limited space. For example, bearings, drive shafts or cables may need to be passed right through the space where traditional rotary encoders might sit. This is where Incoder really provides engineers with technical advantages."
In operation, the Incoder's stator is powered while the rotor is passive; the stator contains all necessary power supply and signal processing electronics, and the electrical output from the stator shows the relative position of the rotor.
Howard states: "Because of the way we have designed the Incoder, there is no requirement for couplings or gears between the main shaft and the encoder. The rotor and stator can simply be screwed directly to the host product. Precise mechanical mounting is not required and there is no need to align bearings." Regarding the Incoder's ability to survive in harsh environments, Howard says: "The Incoder will even survive temporary immersion in salt or fresh water to a depth of up to ten metres."
In harsh environments, the Incoder is unaffected by condensation or dust. Robust aluminium alloy housings and monolithic constructions are used for both rotor and stator. With the Incoder there are no contacting, delicate or wearing parts, which means no periodic replacement, servicing or maintenance. Howard adds: "Incoder already has a solid track record in safety-related applications, including airborne equipment, military manned and unmanned vehicles, and weapons systems."
Although the Incoder works in a similar way to a resolver, it uses laminar windings rather than wire spools, which enables higher measurement performance, a more compact design, low mass and low inertia.
Incoders are available with outside diameters from 75mm (INC-75) up to 250mm (INC-250), although other sizes are available as custom OEM versions.
For more information, visit