Renishaw has announced a dual signal interface for its Tonic incremental optical encoders which, it says, will bring higher accuracy to rotary axis measurements. The DSi interface also gives a selectable reference mark position at the press of a button using Renishaw’s propoZ technology, whose output position is angularly repeatable, regardless of bearing wander or power cycling.

Using two readheads on an angle encoder improves motion system accuracy and repeatability by eliminating eccentricity, bearing wander and “odd” error harmonics. When used with Renishaw’s REXM ring encoders, an accuracy of better than ±1 arc-second is possible. The combined TONiC-DSi system makes adding a second readhead easy by taking care of the combination of incremental channels and reference mark processing.

The system can be used with RESM encoder rings with standard diameters from 52–550mm (and other sizes on request), or with super-accurate REXM rings for high-precision rotary applications.