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RG2/RG4 encoder series

What are RG2 and RG4 ?

RG2 and RG4 incremental encoder systems have a strong reputation established over many years for providing highly-reliable position feedback, even in conditions considered unsuitable for most open, optical linear encoders. They all feature the original Renishaw state-of-the-art filtering optics, with excellent immunity to dust, scratches and light oils on the scale. These systems are fitted as standard by many of the world's leading linear motion OEMs as well as being used in wide-ranging applications such as medical, machine tool, photovoltaics, semiconductor and flat panel display manufacturing.

RG2 is the name given to the range of encoder products that read 20 µm pitch scale types. The range contains a variety of readheads, which differ in size and scale options, including: 

  • robust RGH22
  • compact RGH20 and RGH24
  • low-profile RGH20F and RGH25F*

*The RGH25F is also available as an UHV (Ultra-High Vacuum) version.

Website cameo: RGH22 readhead

RG4 is the name given to the range of encoder products that read 40 µm pitch scale types, permitting even higher speeds and greater set-up tolerances. The range, which differ in size and scale options, consists of:

  • component RGH34
  • robust RGH40, RGH41 and RGH45

Scale options

  • Linear scales are used where straight-line position information is needed - usually X, Y or Z axes.
  • Rotary scales are used for angular position information and the motion control of rotating elements.

Gold plated tape

Gold scale FAQ

Scale name

Accuracy

Scale pitch

Thermal expansion

coefficient

Max length of scale

 

Encoder systems

RGS

±15 µm/m

20 µm/40 µm

Thermally mastered to substrate by use of end clamps

For length >50 m, please contact Renishaw

RGH22 with RGS, RGH24 with RGS, RGH25F with RGS, RGH25F UHV with RGS, RGH34 with RGS, RGH41 with RGS

 

Glass spar

RGS40-G

Scale name

Accuracy

Scale pitch

Thermal expansion

coefficient

Max length of scale

 

Encoder system

RGS40-G

±4.2 µm/m

40 µm

~8 µm/m/°C

1.01 m

RGH40 with RGS40-G

Stainless steel tape with track option

Fastrack RTLR rectangular

Scale name

Accuracy

Scale pitch

Thermal expansion

coefficient

Max length of scale

Encoder system

RTLR with optional FASTRACK

±15 µm/m

40 µm

~10.6 µm/m/°C

 

20 m

RGH45 with RTLR

Stainless steel spar

RELM Invar scale

Scale name

Accuracy

Scale pitch

Thermal expansion

coefficient

Max length of scale

Encoder systems

RSLR

±1.5 µm up to 1 m, ±2.25 µm up to 2 m, ±3 µm up to 3 m, ±4 µm up to 5 m

20 µm

~10.8 µm/m/°C

5 m

RGH20 with RSLR, RGH20F with RSLR

Stainless steel ring 

RESR 3 rings

Scale name

Graduation accuracy

(depending on ring

diameter)

Scale pitch

Thermal expansion

coefficient

Ring diameter

 

Encoder systems

RESR

±3.97 to ±0.38 arc seconds

20 µm/40 µm

~17.3 µm/m/°C

52 to 550 mm

 

RGH20 with RESR,

RGH20F with RESR,

RGH40 with RESR