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VIONiCplus™ incremental encoder system with REXM rotary (angle) ring

Features

  • Digital output direct from the readhead
  • Readhead size: 35 x 13.5 x 10 mm
  • Resolutions to 2.5 nm
  • Speed to 1 330 rpm
  • Ultra-low Sub-Divisional Error (SDE): typically <±10 nm
  • Optical IN‑TRAC™ reference mark

Benefits

  • No separate interface required
  • Advanced Diagnostic Tool for easy fault finding, challenging installations and servicing
  • Thick cross-section ring with installed accuracy of ± 1 arc second
  • High dirt immunity
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What is VIONiCplus?

VIONiCplus integrates Renishaw's filtering optics design and interpolation technology to create a high performance, super-compact, digital all-in-one incremental open optical encoder. It offers resolutions down to 2.5 nm and a wide range of configurations to optimise the speed for your motion control system. VIONiCplus systems are quick and simple to install with wide set-up tolerances and automatic calibration. VIONiCplus implements our latest interpolation algorithms and signal processing techniques to achieve a Sub-Divisional Error of <±10 nm. This is world-leading performance from a 20 µm pitch incremental encoder system.

The Advanced Diagnostics Tool aids fault finding and servicing, and assists optimisation of system setup for challenging installations.

What is REXM ring?

REXM is a one-piece stainless steel ring with 20 µm pitch incremental graduations marked directly onto the periphery, featuring the IN-TRAC™ optical reference mark. Its larger cross-section allows for the reduction of all installation errors apart from eccentricity, which is easily corrected using a DSi (Dual Signal Interface) and two readheads. It features total installed accuracy up to ±1 arc second, zero coupling losses, and exceptional repeatability.
REXM is available in a range of sizes (Ø52 mm to Ø417 mm) and line counts, all of which have a large internal diameter for flexible integration. The non-contact format eliminates backlash, shaft wind-up (torsion) and other mechanical hysteresis errors that are inherent in traditional enclosed encoders.

Why choose this encoder system?

World-leading performance from a 20 µm pitch incremental encoder system

VIONiCplus implements our latest interpolation algorithms and signal processing techniques to achieve a Sub-Divisional Error of <±10 nm. Low SDE directly equates to low velocity ripple which is important for constant velocity applications, such as scanning measurement systems. VIONiCplus' intelligent interpolation chip can achieve 8 000 x interpolation which equates to 2.5 nm resolution directly out of the readhead. This system is used when precision and repeatability is of paramount importance.

Easy fault finding and servicing

The Advanced Diagnostic Tool is available for comprehensive encoder feedback . This can be used for challenging installlations and fault finding. It provides:

  • Remote calibration functions
  • Signal optimisation over axis length
  • Readhead pitch indication
  • Limit and reference mark indicators
  • DRO and lissajous outputs.

Ultra-high installed accuracy

For the ultimate angular metrology, REXM with two VIONiCplus readheads and a VIONiC DSi (Dual signal interface) offers exceptional repeatability, zero coupling losses and better than ±1 arc second total installed accuracy. The REXM features a thicker cross-section designed to minimise all installation errors except eccentricity, which is easily corrected using the combined output of two VIONiC readheads. Once the DSi has eliminated eccentricity, the only other errors remaining are graduation and Sub-Divisional Error - both of which are minimal.

DSi (Dual Signal interface)

VIONiC™ DSi Dual Signal interface

Renishaw's DSi combines the incremental signals from two VIONiC readheads on a REXM ring (REXT ring for partial rotation applications) to compensate for the effect of bearing wander and eliminates odd error harmonics, including eccentricity, to give total installed accuracy of typically ±2.0 arc seconds.


Optional Advanced Diagnostic Tool

VIONiC Advanced Diagnostic Tool

The Advanced Diagnostic Tool (ADT) includes user software that allows control and monitoring of VIONiC's set-up and calibration routines. This set-up tool is ideal for factory production-line installation as it allows remote, advanced calibration features.

Find out more about the Advanced Diagnostic Tool

Technical specifications

Measuring standard

REXM: one-piece ultra-high accuracy stainless steel ring

Also available for partial rotation applications as REXT

Readhead size (LxHxW)

35 mm x 13.5mm x 10mm

Scale pitch

20 μm

Ring outer diameter

52 mm to 417 mm

Line count

8 192 to 65 536 (depending on ring size)

Reference mark

REXM: single IN-TRAC reference mark ring

REXT: two reference mark ring for partial rotation applications

Total installed accuracy (with 2 readheads)

(≥100 mm diameter) ±1 arc second

(75 mm diameter) ±1.5 arc seconds

(≤57 mm diameter) ±2 arc seconds

Maximum speed

1 330 rpm (for 52 mm diameter ring)

(See data sheet for details)

Sub-Divisional Error (SDE)

Typically <±10 nm

Dynamic signal control

Real time signal conditioning including Auto Gain Control (AGC), Auto Balance Control (ABC) and Auto Offset Control (AOC) for optimised performance during operation

Incremental signals


0.1 μm to 2.5 nm resolution

(See data sheet for details of angular resolutions)

Electrical connection

0.5 m, 1 m, 1.5 m, 2 m and 3 m cable lengths with D-type connectors (9 and 15 pin) or circular in-line connector (12 pin)

Power supply

5 V -5%/+10%, typically <200 mA fully terminated

Vibration (operating)

100 m/s2 max at 55 Hz to 2 000 Hz

Shock (non-operating)

500 m/s2, 11 ms, ½ sine, 3 axes

Operating temperature (system)

0 °C to +70 °C

Sealing

IP40

Refer to data sheets for details.

Downloads

Data sheets

Technical drawings

How it works

VIONiCplus features the third generation of Renishaw's unique filtering optics that average the contributions from many scale periods and effectively filter out non-periodic features such as dirt. The nominally square-wave scale pattern is also filtered to leave a pure sinusoidal fringe field at the detector. Here, a multiple finger structure is employed, fine enough to produce photocurrents in the form of four symmetrically phased signals. These are combined to remove DC components and produce sine and cosine signal outputs with high spectral purity and low offset while maintaining bandwidth to beyond 500 kHz.

Fully integrated advanced dynamic signal conditioning, Auto Gain , Auto Balance and Auto Offset Controls combine to ensure ultra-low Sub-Divisional Error (SDE) of typically <±10 nm.

This evolution of filtering optics, combined with carefully-selected electronics, provide incremental signals with wide bandwidth achieving a maximum speed of 12 m/s with the lowest positional jitter (noise) of any encoder in its class. Interpolation is within the readhead, with fine resolution versions being further augmented by additional noise-reducing electronics to achieve jitter of just 1.6 nm RMS.

TONiC™ optical scheme with annotations

The IN-TRAC reference mark is fully-integrated in the incremental scale and is detected by a split photodetector within the readhead. As the diagram shows, the reference mark split detector is embedded directly into the centre of the incremental channel linear photodiode array ensuring greater immunity from yaw-dephasing. This unique arrangement also benefits from an automatic calibration routine that electronically phases the reference mark and optimises the incremental signals.