The Renishaw RLE fibre optic laser encoder uses interferometry to provide high resolution, high linearity position feedback. Laser safety label displayed on rear of laser unit. The RLE system comprises an RLU laser unit and one or two RLD detector heads. The RLU laser unit contains the laser source and signal processing electronics. It is available with one or two fibre optic laser outputs that deliver laser light directly to the RLD detector heads. The detector head is the core of the optical measuring system containing the interferometer optics, novel Renishaw detection scheme and beam steering mechanism(s)*. The RLE range offers a variety of laser units and detector heads to suit specific application requirements - all system components are compatible with each other. The resolution and format of the signals are determined by front panel switches and detector head type. The laser unit also provides system status outputs and allows configuration of signal bandwidth, direction sense and error monitoring. This datasheet describes the RLU20, a laser unit with enhanced frequency stability - see performance details overleaf. Position feedback signals are provided for each axis independently, in either digital quadrature format or analogue quadrature format. Position feedback signals from the RLU can be used directly, or connected via either the RCU10 compensation system (which automatically compensates for air refraction and/or material expansion effects) or via one of the available range of interpolator units to produce an ultra-high resolution output. * The differential interferometer detector head has separate beam steerers for each pair of beams. General outline and dimensions The RLU20 includes an electrical signal input that can be used to shut off the laser beam without destabilising the laser. Fibre projection The RLU can be mounted in any orientation, provided the surface is reasonably flat and free from vibration. Minimum cable and fibre bend radius is 25 mm (0.98).

New Mills, Wotton-under-Edge Gloucestershire  GL12 8JR United Kingdom RLU20 laser unit performance Laser type Output beam intensity HeNe Class II <300 µW (cw) / axis Maximum output power from laser tube <1 mW During preheat this can rise up to 600 µW Laser beam diameter Vacuum wavelength accuracy ±0.1 ppm over three years Laser frequency stability <±1 ppb <±2 ppb <±20 ppb 1 minute 1 hour 8 hours Fibre optic diameter (armoured) Analogue output signal period Plane mirror interferometer Retroreflector interferometer Digital quadrature nominal output resolutions Plane mirror interferometer Retroreflector...