Linear (retroreflector) system

Retroreflector RLE systems comprise an RLU laser unit and (generally) RLD10 detector head(s) configured for use with retroreflector target optics. The retroreflector target is supplied with the detector heads.

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Choice of laser unit is very much dependant on operating environment, with the RLU20 being particularly suited to vacuum and controlled environment applications. RLU10 laser units are used within RLE10 systems, and RLU20 laser units in RLE20 systems.

Detector heads are available for use with either 0° or 90° beam output orientations.  They are also available in low power options for applications requiring a power dissipation lower than the specified < 2 W of the standard RLD.


Data formatDigital - RS422 quadrature
Analogue - 1 Vpp sine / cosine
ResolutionDigital - user selectable to 20 nm (with retroreflector target optic)
Analogue - sub-nanometre via external interpolation (e.g. RPI20 parallel interface)
Maximum velocity2 m/s (when using retroreflector target optic)
Laser typeHeNe (Helium / Neon), 632.8 nm NTP wavelength, Class II 
Laser frequency stability ±50 ppb (RLU10) over any one hour period
±2 ppb (RLU20) over any one hour period
Laser lifetime >50,000 hours
Maximum axis length4 m (when using retroreflector target optic)

For non-vacuum applications, some form of refractive index compensation is required to maintain accuracy under fluctuating environmental conditions. Renishaw offers the RCU10 real-time quadrature compensation system to compensate for these variances. Renishaw supplied retroreflector may not be suitable for use with vacuum or near vacuum applications.

Resolutions to 38.6 picometres can be achieved by integrating an RPI20 parallel interface into the RLE system (plane mirror configuration). For enhanced resolution with a digital output, the REE series of Renishaw interpolators can offer resolutions of up to .395 nm (plane mirror configuration). This interface accepts differential analogue 1 Vpp sine / cosine signals and provides a parallel format output. See Accessories for information on the RCU10 compensation system, the RPI20, REE and other auxiliary equipment for use with RLE systems.


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Contact us online if you require more information or you have a pricing query, or alternatively you may like to speak directly to your local Renishaw office.