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RESOLUTE™ FS absolute encoder system with RELA linear scale

Features

  • Protocol available: DRIVE-CLiQ
  • Readhead size: 36 x 16.5 x 17.2 mm
  • Resolutions to 1 nm at 100 m/s
  • ±1 µm accuracy at 20 °C
  • Scale thermal coefficient of expansion at 20 °C:                         0.75 ±0.35 µm/m/°C
  • Certified to:
    ISO 13849:2015 PLd
    IEC 61508:2010 SIL2
    IEC 61800-5-2:2007 SIL2

Benefits

  • Very high accuracy combined with near zero thermal expansion
  • Excellent motion control performance
  • Exceptionally high dirt immunity
  • Wide set-up tolerances
  • Less than 10 nm RMS jitter for improved positional stability
  • ±40 nm Sub-Divisional Error for smooth velocity control

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What is RESOLUTE FS?

RESOLUTE FS (Functional Safety) is a true absolute, fine pitch optical encoder system that has excellent dirt immunity, and an impressive specification that breaks new ground in position feedback. It is the world's first absolute encoder capable of 1 nm resolution at up to 100 m/s. Ultra low SDE and jitter result in a rotary encoder system that outperforms any other encoder in its class. Certified to SIL2 and PLd for use in functional safety applications.

The Queen's Award for Enterprise: Innovation 2015

 

RESOLUTE true-absolute 30 µm encoder system, winner of the Queen's Award for Enterprise 2015 in the Innovation category

What is RELA scale?

RELA is a spar scale manufactured from ZeroMet, a low expansion nickel/iron alloy, featuring our 30 µm pitch absolute scale code. 
It is comparable to fine pitch glass scales and offers a total accuracy (including slope and linearity) better than ±1 µm up to 1 m length. ZeroMet has a thermal expansion coefficient of 0.75 ±0.35 µm/m/°C at 20 °C.
System designers can choose between specially formulated adhesive tape or mechanical clips to suit mounting requirements. Both mounting methods allow for independent thermal expansion to that of the substrate.

Why choose this encoder system?

Functional Safety certification

RESOLUTE FS is a true absolute open optical encoder system with certification to the following functional safety standards:

ISO 13849:2015 PLd
IEC 61508:2010 SIL2
IEC 61800-5-2:2007 SIL2

Certain machinery safety functions, such as Safety Limited Speed (SLS), require the encoder feedback to be functionally safe. Utilising an encoder system that is already rated for use in these applications can make machine certification significantly easier. Adopting these advanced machine safety functions allows machine builders to make safer machines, capable of higher functionality that reduce set-up times and machine downtime.

Excellent motion control performance

RESOLUTE FS's industry-leading performance is the result of a sophisticated, reliable and innovative method of operation. Crucially, the system uses a single track non-repeating “bar code” scale format with a nominal pitch of 30 µm. With its sophisticated optical design the RESOLUTE FS readhead captures a near-instantaneous image of this scale which, when analysed, allows a unique position to be identified at speeds of up to 100 m/s. The system allows position to be determined with resolution as small as 1 nanometre (1 billionth of a metre) and with low noise (jitter below 10 nm RMS) and SDE (Sub-Divisional Error, the error within a scale period) of just ±40 nm. This provides encoder feedback of superior fidelity, to ensure smoother velocity control and rock-solid positional stability.

Wide set-up tolerances

RESOLUTE FS does not follow the conventional technique of using dual tracks side-by-side (one incremental, one absolute) which inherently suffers de-phasing problems when small amounts of angular misalignment are introduced. Instead, this absolute encoder features a single track, optical absolute scale, combining both the absolute position and embedded phase information into one single code. This technology provides RESOLUTE FS with far wider set-up tolerances (yaw tolerance ±0.5°) for quick and easy installation and superior long-term reliability, even if the motion axes settle or move over time. To further aid installation and diagnostics, there is an integral set-up LED on the readhead.

Interface option 

DRIVE-CLiQ interface

  • DRIVE-CLiQ interface for use with the RESOLUTE true-absolute optical encoderRequired for DRIVE-CLiQ protocol
  • Also available in dual head input for high accuracy rotary systems
  • Displays communication alarms
  • Duplicates readhead LED

Protocol

ProtocolDescriptionData sheetCompatible products

DRIVE-CLiQ

RESOLUTE FS with Siemens DRIVE-CLiQ serial interface is available for linear and rotary applications. DRIVE-CLiQ is the innovative, powerful communications interface to connect encoder and direct measurement systems with SINUMERIK and SINAMICS drive components.

RESOLUTE FS DRIVE-CLiQ

 

N/A

Technical specifications

Measuring standard

RELA: absolute coded high accuracy ZeroMet spar scale

Readhead size (LxWxH)

36 mm x 16.5 mm x 17.2 mm

Scale pitch

Nominal 30 μm

Thermal expansion coefficient at 20 °C

0.75 ±0.35 μm/m/°C

Accuracy grade at 20 °C

Certified to ±1 μm, calibrated traceable to International Standards

Scale length

(See data sheet for details)

80 mm to 1.5 m

Maximum speed

(See data sheet for details)

100 m/s

Protocols*

DRIVE-CLiQ†         

Resolutions

DRIVE-CLiQ†: 50 nm and 1 nm resolutions

Sub-Divisional Error (SDE)

±40 nm

Electrical connection

Up to 9 m cable lengths and M12 connector for DRIVE-CLiQ interface

Power supply

5 V ±10%, max 250 mA @ 5 V (terminated)

Vibration (operating)

300 m/s2max @ 55 Hz to 2 000 Hz

Shock (non-operating)

1 000 m/s2, 6 ms, ½ sine

Operating temperature

0 °C to +80 °C

Sealing

IP64

Refer to data sheets for full details.

*Other protocols are continually being added.

For DRIVE-CLiQ specifications, refer to data sheet.

Downloads

Data sheets

Installation guide & safety manual

White papers

Technical drawings

How it works

RESOLUTE communicates bi-directionally in purely serial format, using a variety of industry-standard protocols, of both proprietary and open standard. 

RESOLUTE™ encoder optical scheme with annotations

The process begins...

The controller initiates operation by sending a demand message to the readhead, instructing it to capture the absolute position on the linear or rotary scale at that instant. The head responds by flashing a high-power LED source to illuminate the scale. The flash duration is as brief as 100 ns to minimise image blur on moving axes. Crucially its timing is controlled within a few nanoseconds to preserve the relationship between demanded and reported position, one of the essential features that makes RESOLUTE ideally suited to very high specification motion systems. 

 

 

Single track scale

The scale is essentially a single track of full-width contrasting lines, based on a nominal period of 30 µm. The absence of multiple parallel tracks gives important immunity from yaw errors and much more lateral tolerance in head position.

Image acquisition

The scale is imaged, via an aspheric lens which minimises distortion, onto a custom detector array designed specifically for RESOLUTE. The optical arrangement, with a folded illumination path but direct imaging, is highly compact yet stable thus assuring the fidelity essential for excellent metrology.

Data decoding and analysis

Once captured by the detector, the image is transferred via an analogue-to-digital converter (ADC) to a powerful Digital Signal Processor (DSP). Specially developed algorithms then obtain a true absolute, but relatively coarse position from the code embedded in the scale. This process is checked, and corrections are made by further algorithms in the DSP which exploit redundancy and intentional restrictions in the scale code. Meanwhile other routines calculate a very high resolution fine position, which is then combined with the coarse position to provide a truly absolute and very high resolution location.

Final checks and data output

After final error checking procedures this information is uploaded in the appropriate protocol to the controller as a pure serial word representing position to within 1 nm. Protection against electrical noise disturbance is provided by addition of a Cyclic Redundancy Check (CRC). The entire process can take as little as a few micro seconds and be repeated up to 25 000 times per second. By a variety of techniques, including adjusting the light flash duration to the axis speed, this performance is achieved at up to 100 m/s while, crucially, preserving exceptionally low positional jitter at lower operating speeds.

And the result is...

An encoder with generous installation tolerances: RESOLUTE allows ±0.5° in yaw, pitch and roll and an impressive ±150 µm in rideheight. Meanwhile the generous optical footprint and advanced error correcting procedures confer excellent immunity to optical contamination, both particulate and greasy smears. All this while maintaining 1 nm resolution at 100 m/s: RESOLUTE is the answer to the toughest absolute challenge.