One of a handful of British exhibitors at the recent SPS/IPC/Drives exhibition in Germany was Renishaw which was showing a compact, non-contact optical encoder that supports speeds of up to 10m/s and resolutions down to 5nm for both linear and rotary applications.

The Tonic system is designed to avoid the compromise between speed and accuracy usually faced by motion designers. Renishaw says it delivers better resolution, signal stability and long-term reliability than its previous high-speed, non-contact encoders, at a similar price.

The auto-calibrating encoder uses a new version of Renishaw’s flexible gold tape scale with its In-Trac reference mark embedded into the incremental channel, ensuring that phasing is retained through the whole speed and temperature range (up to 70˚C).

The readheads include a pair of diagnostic LEDs as well as dynamic signal processing circuitry which provides a sub-divisional error of ±30nm. There is a choice of a digital signal output or analogue 1V_pp directly from the readhead. An auto gain control compensates for dust, scratches and oil on the scale.