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• High speed, high resolution
• Excellent accuracy
• Easy installation
• Wide range of output options, for both analogue and digital versions
• Open non-contact system = high speed
• zero mechanical hysteresis

The RGH22 readerhead is designed for the designer:

• Low readerhead swept volume
• Common dimensions for all readerheads
• Fully screened integral cable is thin and very flexible
• Unit of resolution reference mark available
• Set-up LED and low signal warning available throughout the range
• Industry standard voltage and micro-amp outputs
• Very good dirt immunity

The RG2 encoder system

The award winning RG2 encoder system provides high resolution positional feedback for a wide range of precision machine control applications. The RG2 has been designed to meet the most demanding specifications for precision positional feedback. Linear measurement, motion, scanning and semi-conductor processing are typical of the many hi-tech applications benefiting from the RG2's high resolution with speeds of up to 10m/sec.

Innovative design

As an optical, reflective, non-contact encoder, the RG2 system comprises a readerhead (analogue or digital output) and an exceptionally stable but flexible, 20µm pitch scale. The choice of readerhead depends the application, but conveniently the same gold scale is used for all applications. To add to the simplicity, the RG scale is applied using the innovative RGA22 applicator which not only ensures perfect alignment with the path of the readerhead, but it simultaneously strips the backing tape from the scale at a uniform rate, guaranteeing excellent linear performance of the laid scale.

Performance and integration

The RG2's performance meets the highest accuracy standards set by today's leading engineering and scientific applications and wherever it is used the RG2 system is easily integrated into whole machines or motion system sub-assemblies.

The RG2 also provides many installation and production advantages not usually addressed by other encoder systems.

For system designers, the use of rigid scale/open encoders has, traditionally posed a number of difficulties. The scale's rigidity combined with its fragility are problem enough, yet traditional open encoders are notoriously prone to failure caused by the slightest amount of contamination on the scale. No such problems with the RG2 - not surprising then, the RG2 is fast becoming the preferred open encoder system for use in the workshop environment.

Readerhead configurations

The new RGH22 readerhead series is available in the following options:

Industry standard output signal formats

Digital readerhead resolution

N.B. Higher speeds are possible, please contact Renishaw for further information.

RGH22 readerhead optics

The optical system, based on Renishaw's unique spatial filter and light scattering reflective scale, incorporates a electro-optic arrangement. Key features include absolute Lissajous centering, greater accuracy and much improved tolerance to both dirt and readerhead alignment. Because cyclic error (sub-divisional error) has been minimized, short range errors are in the order of 0.1 µm and overall system repeatability is improved.

The reference mark

The RGH22 series readerheads all incorporate a magnetically actuated reference mark. Improved signal processing guarantees correct format pulse regardless of set-up, while full performance is maintained in magnetic fields up to 200 gauss stable and 75000 gauss/s alternating. Positional accuracy is repeatable to one unit of resolution.