New Kit Encoders For Improved Motor Feedback

The new kit encoders form a powerful and attractively priced alternative to classic resolvers that only have an analog interface and can only detect a single revolution. The easy-to-install magnetic installation kits are available either as absolute multiturn-capable sensor systems and from the beginning of 2017 also in incremental versions.

Self-sufficient rotation counter

The components of the new kit encoders include an electronics package (d: 36 mm), which is housed on a compact circuit board, and a small permanent magnet that can be attached to the end of the motor shaft. The electronics package includes four Hall sensors, a powerful 32-bit microprocessor and an energy self-sufficient rotation counter operated via the Wiegand effect.

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The clever supply system is based on the 'Wiegand-Wire' technology marketed by Posital worldwide and makes batteries or complex transmission systems superfluous. The magnetic wire specially manufactured by Posital in the USA acts as an energy harvesting system. Regardless of the speed of a rotary movement, it generates high-energy voltage pulses and supplies enough energy to constantly activate the rotation counter and the associated electronics. This proven principle guarantees maintenance-free, absolute multiturn position measurements.

Shock and vibration resistant

As the contact-free measuring technology from Posital - unlike optical systems with code disks and complex gears - has no moving parts, it proves to be extremely shock and vibration resistant. While optical installation kits require installation conditions similar to clean rooms, the magnetic posital kits are much less susceptible to dust and moisture. They can be easily installed under normal factory conditions.

The new installation kits are available with various manufacturer-neutral digital communication interfaces such as BISS or SSI for absolute measurements as well as UVW and ABZ for commutation and incremental encoders. In addition, protocols based on the RS 485 interface can be implemented. "While a large number of commercially available optical installation kits come with proprietary interfaces and thus create a direct dependency of the motor customer on the encoder manufacturer, we deliberately chose a different path," said Jörg Paulus, Germany and Europe director at Posital. "We are vehement advocates of open source interfaces."

Available in two versions

The kit encoders are designed in two versions: as absolute multiturn-capable sensor systems, they come with an electronic resolution of 17 bits or, in multiturn position measurement, with a range of more than one million revolutions. A second variant offers a combined output of incremental and commutation signals (UVW) with up to 16,384 pulses per revolution (PPR). The new motor feedback systems are designed for a temperature range from -40 to 105 ° C. Compact and inexpensive shielding accessories are available to target the electronic components and Hall sensors against external magnetic fields - e.g. B. when installed in a motor in close proximity to a magnetic brake - to protect.

The technological basis of the new installation kits is the high-resolution magnetic rotary encoder of the IXARC series from Posital, which has been on the market since 2013. Thanks to 16-bit resolution and an accuracy of 0.09 °, they quickly established themselves as an alternative to the sensors with optoelectronics traditionally used for precision applications. "What we have successfully developed for IXARC with great effort, we can now give motor manufacturers as a kit solution," says Christian Leeser, majority shareholder and CEO of the Fraba Group, which also includes Posital. Thanks to new filter algorithms for signal processing, the latency times have been significantly reduced, so that precise motor control is possible even in highly dynamic applications. "With our kits we create a completely new product,that is positioned between the classic resolvers and optical scanning systems - and redefines the market in terms of performance and price.”(jv)