New Hollow Shaft Multi-Turn Kit Encoders For Position Control Applications

Slim Form Factor for Motor and Machine Manufacturers

POSITAL is introducing a new family of absolute rotary encoders for servomotors, stepper motors, robot joints and anywhere else a hollow center design is needed to achieve an optimal mechanical layout. Both single and multi-turn variants are available; for multi-turn models, the rotation counter is self-powered, using POSITAL’s Wiegand energy-harvesting technology. This eliminates the need for backup batteries and lowers maintenance costs.

- Hollow Center Design for Optimal Mechanical Layout on Robotic Joints and Drives Shafts

- 30 mm or 50 mm Internal Diameter Sizes Available

- Battery-less Rotation Counter Based on Energy-Harvesting Technology

- Capacitive Measurement System Allows for High Accuracy Even in Harsh Environments

- Non-Proprietary Interfaces of SSI and BiSS C Standards

Capacitive Measurement Technology

These new products make use of a capacitive measurement system. Each encoder has two principle components, a stator and rotor, both containing specially shaped conductive surfaces. These surfaces, which function as capacitor plates, are positioned in close proximity. As the rotor turns, the patterns of the conductive surfaces change their relative position, causing changes to capacitive coupling in the system. This in turn causes changes to the amplitude and phase angle of a high-frequency electrical signal generated by exciter circuits in the stator. Special ASIC devices capture and decode these signal variations to determine the rotor’s angular position to a high level of precision.

The new POSITAL hollow shaft kit encoders offer excellent accuracy (+/- 0.02°) and dynamic response (up to 6000 RPM), making them suitable for use in critical motion control systems. However, what makes them especially useful in many applications is their shape. Both stator and rotor elements are in the form of disks with large central openings. This makes them an ideal choice in space-limited situations, such as servomotors, stepper motors or the joints in robotic arms , where it is desirable to have an embedded position sensor fitting around a central shaft or axle.

POSITAL hollow shaft kit encoders will be available in two sizes, with 30 mm or 50 mm internal diameters. Non-proprietary SSI and BiSS C communications interfaces are supported.