Encoders                                                                     

RGH25 UHV series
Ultra high vacuum compatible readhead
Ultra high vacuum version of the RGH25 readhead for use in scientific applications.

RGB25 interface series
Interpolator unit for use with RGH25U readhead series
Encoder cables
Extension cables for encoder systems
End clamp options
Fixing mechanisms for flexible scale
Reference mark options
Magnetic actuator device used to find home position
Limit switch options
Magnetic actuator device used for limit detection
RGH24/25 applicators
Scale applicator devices for RGH24/25 readheads
RGS20-S - 20µm tape scale
20µm pitch flexible tape scale
RGF interpolator series
RGH25F Interpolator units for up to 500x
RGH25UHV readheads
UHV compatible - low profile readheads

RGB25 interface series
Interpolator unit for use with RGH25U readhead series The RGB25 interface is used to process the signals from the RGH25U readhead into industry standard formats. Outputs are available in both digital and analogue quadrature.

Interpolation factors available provide resolutions to 50nm. RGB25 interfaces
For use with RGH25 readheadsThe RGB25 interface can be mounted at a suitable location away from the readhead, using double sided adhesive tape or the specially designed interface brackets.

Interpolation factors provide resolutions of 5, 1, 0.5, 0.1 m and 50nm. Analogue outputs are available in 1Vpp and 12 A.Bracket options
Mounting brackets for all products

A range of brackets are available to allow easy mounting of RGB and RGE interfaces and RGH22,40 and 41 readheads.

Encoder cables
Extension cables for encoder systems

All readheads are available with a range of connectors to choose from. Extension cable can be purchased as required from Renishaw.

Permitted maximum cable length by readhead type :

1Vpp - 100m, 12µA - 30m, Digital - 20m+ (depending on exact model)

14 core - double screened extension cable - additional sensing cores enable the voltage monitoring at the readhead to ensure voltage drop over long distances can be compensated for. Suitable for all readheads.

8 core - double screened readhead cable - used with RGH24/25 series readheads.

12 core - double screened readhead cable - used with RGH22/41 series readheads.

End clamp options
Fixing mechanisms for flexible scale

There are two methods used for mastering tape scale to substrates;

• Adhesive end clamps use a specially formulated 2-part epoxy to fix the clamps at each end of the axis to ensure that the scale matches the thermal behaviour of the substrate
• Where adhesive end clamps are inappropriate, mechanical bolt-down end clamps are also available

Reference mark options
Magnetic actuator device used to find home position

Reference mark outputs are optional on all readhead models to provide a repeatable home or zero position. Compact magnetic actuators are positioned at one or more user-defined locations adjacent to the scale, which the readhead senses when passing.

There are two types of reference mark :

• Standard reference mark : magnetic reference mark actuators - reference pulse triggering device for mounting on the substrate adjacent to the scale
• 90° mount reference mark : magnetic reference mark actuators, mounted vertically for use with RGH24/25 readheads
  Actuators are premounted on a convenient bracket for easy installation

Limit switch options
Magnetic actuator device used for limit detection

Limit switch outputs are available as an option on all readhead models and on certain models, dual outputs are also available. As an end of travel indicator, compact magnetic actuators are positioned at the end of each axis adjacent to the scale, which the readhead senses when passing.

Limit switch options :

• Limit switch actuators - mounted horizontally adjacent to the scale, trigger the sensor inside the readhead when the readhead passes over the actuator
• 90° mount limit switches - vertically mounted limit switch actuators for use with RGH24/25 readheads

RGH24/25 applicators
Scale applicator devices for RGH24/25 readheads

Scale installation is made quick and easy using dedicated application tooling, which ensures the scale is positioned accurately along the entire axis length. The release paper is manually or automatically removed as the scale is installed using the movement of the machine axis.

Using a simple jig, the readhead, reference mark and limit switch actuators are correctly located relative to the scale. The readhead set-up LED indicates when optimum alignment is achieved; all that remains is the installation of the adhesive end clamps.

• Easy scale installation - applicator tool enables rapid scale installation Unique applicator devices - enables quick and easy installation No need for drilling or tapping
• Parallelism of scale with respect to the axis guaranteed every time

RGS20-S - 20µm tape scale
20µm pitch flexible tape scale

The scale used by all RG2 readheads is made from a thin flexible steel strip, which is gold plated to give high reflectivity and corrosion resistance. A tough lacquer coating provides handling resistance and allows easy cleaning.

It is attached by means of an adhesive backing tape to most engineering materials, including metals, ceramics and composites. Long continuous scale can be supplied on a reel and cut to length at the point of installation ensuring minimum waste and efficient inventory management. Features include :

• Easy scale installation - applicator tool enables rapid scale installation Ordering flexibility - cut to suit scale and common scale for each range Available on a reel - scale can be cut to suit any axis length Lengths up to 70m - compatible with even the largest machines
• RGS-S scale is designed to match the thermal behaviour of the substrates is affixed to, simplifying thermal compensation

RGF interpolator series
RGH25F Interpolator units for up to 500x

RGF series interpolators are designed to work with the RGH25F readheads and can output RS422 digital quadrature to 10nm resolution. Features include :

• Excellect repeatability and reliability with resolutions as high as 50nm, 20nm and 10nm Speeds of 300 mm/s at 20 nm and greater than 150 mm/s at 10 nm
• Better than 0.1 µm accuracy

RGH25UHV readheads
UHV compatible - low profile readheads

The RGH25 is available in Ultra High Vacuum (UHV)compatible format for use in scientific applications requiring operation in ultra high vacuum environments.

The RGH25 UHV can be put through extended 'bake-out' cycles at up to 120° to minimise outgassing. The RGH25 UHV has an excellent RGA spectrum with a negligible hydro-carbon signature. Key benefits and features include :

• Non-contact design enables high speed operation without wear Solid state technology to ensure long term reliability Easy readhead set-up using set-up LED and setting shim (gauge) High accuracy, linearity and repeatability Lissajous (signal) stability to minimise cyclic errors
• Low mass - minimises inertia of the system

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