RESM rotary/angle encoders from Renishaw (Hoffman Estates, IL) combine stainless steel mounting ring/scale and dirt-filtering options with signal processing and IN-TRAC™ auto-phase bidirectional optical reference mark. The device offers speeds to 3,600 rev/min and accuracy to ±0.5 arc seconds, with resolution and repeatability to 0.02 arc seconds. The encoders are available in a range of shaft diameter sizes from 52 to 413 mm.

The device is rated for temperatures to 85°C. Its taper mechanism corrects for eccentricity of the mounting shaft. The Si interfaces can be mounted remotely and a small connector on the readhead cable enables feed-through where access is restricted.