Non contact chip encoders measure up

Magnetic chip encoders can measure angles to fractions of a degree for only a few euros each. Not made in China but Slovenia, under part British ownership, the latest devices from RLS in Ljubljana form a range of products that set new standards for low cost position sensing devices. The RMB kit encoders, as they are designated, use a 4mm magnet and 64 Hall detectors contained with an integrated circuit mounted on a small PCB that may be no more than 20mm in diameter. According to sales and marketing manager Tom Mackintosh, they can be supplied as bare chips "For a few euros", as PCB units, or as sealed units suitable for use in the food industry. Unlike conventional optical encoders that have seals that can fail over time, these encoders use a non-contact design that ensures long term reliability, as well as being much more rugged and giving an absolute readout from the basic device. Resolution is to 12 bits which translates to better than 0.08 degrees. Standard products include the AM256 that produces industry standard absolute, incremental and sinusoidal outputs, with 8-bit resolution for absolute positioning and giving 64, 128 and 256 incremental counts per revolution. The AM512B has 9-bit resolution and 512 counts per revolution incremental while the AM8192 resolves to 13 bits, 8192 counts per revolution incremental. Depending on resolution, speeds of up to 60,000 rpm can be achieved. Applications include resolver replacement in brushless DC motors using the AM256 and pan and tilt control in security companies. RLS is part owned by Renishaw. RLS merilna tehnika d.o.o.