Faster More Accurate 13-Bit Magnetic Rotary Encoder

Renishaw has upgraded its 13-bit magnetic rotary encoder-on-chip to higher speeds, better noise control, improved time delay and accuracy, plus unique performance tailoring capability. The enhanced RLS AM8192B encoder increases operational speeds to 38,000 rpm at 13-bit resolution (60,000 rpm at 12 bit), while a simple software interface allows designers to choose optimum settings for applications, as well as providing a HEX setting file for easy upload.

Delivering 8192 counts per revolution, the solid-state, non-contact design gives OEMs affordable, high-reliability solutions to difficult and extreme operating conditions. The high-performance magnetic encoders offer -40°C to 125°C operational temperature range with superior shock and vibration resistance. Frictionless, low-inertia operation enables consistent, wear-free 0.3° positioning accuracy at high speeds, acceleration and deceleration.

The simple non-contact design of separate magnet and ASIC eliminates hysteresis, wear, friction, and the need for seals and bearings, assuring long-term reliability. The ASIC contains an array of Hall-effect sensors that generates a voltage when exposed to the magnetic flux field. Sine and cosine voltage outputs vary with magnet position, which the ASIC interpolates as a range of binary and decimal resolutions. Analog signals are converted to position data using a configurable interpolator (up to 13 bit). Through creative design, the ASIC is able to cancel magnetic interference, permitting operation in areas of high external magnetic fields.

Encoder resolution is configurable using an external EEPROM while the Hall sensor array is already factory-trimmed for optimum performance. The absolute angle position value can be accessed though an SSI interface. Relative changes of angle position are simultaneously output as incremental A QUAD B encoder signals at up to 8192 counts per revolution. Simultaneous SSI and incremental capability enables the 13-bit AM8192B encoders to be used for both motor commutation and velocity control at the same time.

The encoder-on-chip configuration allows the AM8192B to be easily engineered and integrated into machine designs. The ability to operate with a gap between the magnetic actuator and encoder chip meets design needs for isolation of moving elements. The AM8192B encoder-on-chip uses 5 V power supply and is RoHS (lead free) compliant.

The RLS rotary magnetic family covers 8, 9, 10, 11, 12 and now 13-bit sensors, all available in chip, chip on board, and packaged/encapsulated versions. This gives designers everything from 64 ppr to 8192 counts per revolution to fit a wide range of applications. Besides motor feedback and positioning control, the magnetic products are used for torque sensing, flow control, scanning, and instrumentation. They are ideal for price-competitive applications, such as industrial power tools, vending machines, CCTV, and valve positioners. Linear voltage or current output versions can be used in applications such as panel switches, where potentiometers have traditionally been used.