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Following its recent acquisition by the Variohm Group, Phoenix America’s unique range of magnetic encoders and sensor components are now fully available from sensor and measurement specialist Variohm EuroSensor. With UK- and German-based sales teams and distribution partners throughout Europe and in many global industrial countries, Variohm EuroSensor will provide complete technical sales and application support for Phoenix America’s comprehensive product range including the magnetic rotary encoders covered in this application note.

Phoenix America’s rotary magnetic encoder kits employ proven Hall Effect principles in two-part, bearing-less and non-contacting designs comprising a multipole magnet ring moulded from bonded magnet compounds enclosed by a thermoplastic housing containing the sensing devices and signal conditioning electronics. These modular components employ disc or rectangular shaped sensor housings that interact with the separate ‘target rotor’ where its varying number of radially magnetised poles determines the quadrature square wave output, providing resolutions from 4 to 10,000 counts per revolution as the target magnet rotates.

The classic installation configuration involves the target rotor magnet being attached to a motor shaft or other rotating element whilst the signal conditioning module is held fixed by its attachment to the motor housing. Pulses are delivered as single-ended (Channel A and B) or differential pulses A+, A-, B+ and B-), and thus when read into servo or other control/measurement systems correspond to bi-directional position, speed and acceleration. This robust design principle - non-contacting, without bearings and consisting of two encapsulated and fully sealed components - provides an exceptionally high degree of durability and a practically unlimited working life. Furthermore the technology competes very favourably on price with optical encoders where it also offers substantial benefits in terms of reliability and durability, especially where harsh environments prevail.

Phoenix America’s magnetic encoders are extensively used and proven in feedback and measurement applications that include closed loop motion control and position and/or speed verification on brushed, brushless and stepper motors as well as industrial motors where frequency inverter drive manufacturers are now commonly including high accuracy position control, and which tends to be especially associated with harsh environment use. Other application areas include valve control and flow sensing, renewable energy, plant and processing machinery, robotics and more.

Phoenix America’s standard range of rotary magnetic encoders’ cover low and high resolution kit encoder variants in a wide choice of design configurations that suit motor mounting or other types of driven shaft mounting for maximum installation flexibility. Essentially for motor mounting, both the L-series and H- series kit encoders (Low and High resolution) employ encapsulated disc-shaped modules and are used with target rotor magnets which feature a pass-through hole for motor shaft mounting. A wide choice of disc diameters up to approximately 60 mm offer binary or decade outputs, typically from 2 to 30 PPR (pulses per rev) in the low resolution range and up to 2560 PPR for the high resolution range. Typical output characteristics are bi-directional two channel incremental quadrature output for 512, 1024, and 2048 pulses per channel with differential RS422 compatible output options. The mating target magnets for these two product designs suit motor shafts up to 28.6 mm diameter (1.125 inch) with larger shafts and associated disc modules accommodated outside the standard range. Disc modules are also available with central through holes to allow the motor shaft to extend or to aid front (drive) shaft or gear unit mounting etc. Both 5 V and 24 V powered versions are available with corresponding industry-compatible square-wave output options. The pulse output frequency bandwidth varies with model size and resolution and is typically sufficient to handle most high speed applications.

M series and N series magnetic encoders employ similar principles to the L and H series but the main magnet and signal conditioning module is in the form of a rectangular housing that is mounted axially alongside the target rotor which is available with bore diameter up to approximately 14.83 mm (2.75 inches) - thus allowing installation on much larger motors, or for convenient mounting for other types of rotating equipment. High resolution variants up to 5000 PPR are available in decade and binary output versions with two channel quadrature output from an industry-standard 7272 line driver, as single-ended and differential.

Throughout the standard H, L, M and N series magnetic encoder product lines, the operational temperature range is -40 to +125 ⁰C providing ample scope for the harshest of environments. Flying lead and Molex or AMP connectors are specifiable for electrical interfacing with custom mounting and other customer-specific matched requirements on request.

Phoenix America’s design and manufacturing capability extends to a wide range of other magnetic based sensing technologies that include speed and proximity sensors, sensor magnets, gear tooth sensors, hall commutators, magnet assemblies as well as a custom design services for other specialised magnetic sensor applications. Variohm EuroSensor will also fully support these product lines across all of its sales channels.

Variohm EuroSensor combines several years’ of sensor and measurement applications experience as a designer and manufacturer with its own product range and through distribution partnerships with several globally leading sensor component suppliers. For complete information on the Phoenix America range of magnetic technology products, call +44 (0) 1327 351004, email This email address is being protected from spambots. You need JavaScript enabled to view it. or visit For specific Phoenix America product data sheets, visit 

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