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VIONiC™ incremental encoder system with RESM20 rotary (angle) ring


  • Digital output direct from the readhead
  • Readhead size: 35 x 13.5 x 10 mm
  • Resolutions to 2.5 nm*
  • Speed up to 4 400 rpm
  • Ultra-low Sub-Divisional Error (SDE): typically < ±15 nm* (see tech. spec.)
  • Optical IN‑TRAC™ reference mark


  • No separate interface required
  • Advanced Diagnostic Tool for easy fault finding, challenging installations and servicing
  • Low profile ring with large internal diameter for easy integration
  • High dirt immunity
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What is VIONiC?

The VIONiC encoder series integrates Renishaw's market-proven filtering optics and signal processing for superior metrology performance.

VIONiC encoders feature intelligent interpolation technology to give a digital output direct from the readhead. This provides ultra-low Sub-Divisional Error (SDE) and excellent dirt immunity, without the need for additional adaptors or separate interfaces. It also benefits from a compact footprint, without compromising on performance.

VIONiC readheads are compatible with a wide range of linear, partial arc and rotary scales.

Additionally, VIONiC encoders are designed with intuitive auto calibration mode and are easy to install. An optional Advanced Diagnostic Tool ADTi-100 is available for real‑time encoder data feedback during installation or for in-field diagnostics.

What is RESM20 ring?

RESM20 is a one-piece stainless steel ring with 20 µm pitch incremental graduations marked directly on the periphery, featuring the IN-TRAC™ optical reference marks. Two versions are available in a wide range of sizes (Ø52 mm to Ø550 mm): ‘A' section rings, which offer an impressive installed accuracy and feature a taper mount system which reduces the need for highly toleranced machined parts and eliminates eccentricity; ‘B' section thin rings, which have low inertia and mass, are also available. Both 'A' and 'B' section rings 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 ?

Renishaw's highest performing incremental optical encoder

The VIONiC encoder series combines high-speed operation with fine resolution. The VIONiC readhead features an intelligent interpolation chip to give resolution as fine as 2.5 nm, offering high precision and repeatability in any application. The VIONiC encoder is available with a maximum clock rate of 50 MHz and operates at speeds up to 12 m/s. Speeds of up to 3.63 m/s are possible at a resolution of 0.1 μm, ideal for maximising throughput in the most demanding manufacturing processes.

Easy fault finding and servicing

The Advanced Diagnostic Tool ADTi-100 together with the ADT View software is available to provide comprehensive real-time encoder data feedback for more challenging installations and in-field diagnostics. This is especially helpful in applications when the encoder is hidden within a machine, enabling live diagnostics with minimal machine downtime. The intuitive software interface can be used for:

  • Remote calibration
  • Signal optimisation over the entire axis length
  • Readhead pitch indication
  • Limit and reference mark indication
  • Digital readout of encoder position (relative to the scale)
  • Monitoring the velocity against time graph
  • Exporting and saving data

High dirt immunity

High tolerance to dirt, scratches and greasy fingerprints and speeds of 12 m/s mean that VIONiC is ideal for more challenging applications. Furthermore, the non-contact RESM20 operates without friction or wear ensuring excellent reliability.

DSi (Dual Signal interface)

VIONiC™ DSi Dual Signal interface

Renishaw's DSi combines the incremental signals from two VIONiC readheads on a RESM ring (REST 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 ADTi-100

Advanced Diagnostic Tool ADTi-100

The VIONiC encoder system is compatible with the Advanced Diagnostic Tool ADTi-100 and ADT View software. They provide comprehensive real-time encoder data feedback to aid more challenging installations and diagnostics. The intuitive software interface can be used for:

  • Remote calibration
  • Signal optimisation over the entire axis length
  • Readhead pitch indication
  • Limit and reference mark indication
  • Digital readout of encoder position (relative to the scale)
  • Monitoring the velocity against time graph
  • Exporting and saving data

Technical specifications

Measuring standard

RESM20: one-piece low profile stainless steel ring. Standard ‘A' section with tapered internal diameter or low inertia ‘B' section rings available

Also available for partial rotation applications as REST20

Readhead size (LxHxW)

35 mm x 13.5 mm x 10 mm

Scale pitch

20 μm

Coefficient of thermal expansion at 20 °C 15.5 ±0.5 μm/m/°C

Ring outer diameter

52 mm to 550 mm. For larger custom sizes, contact Renishaw

Line count

8 192 to 86 400 (depending on ring size)

Reference mark

RESM20: single IN-TRAC reference mark ring

REST20: two reference mark ring for partial rotation applications


Graduation accuracy

System accuracy

±3.97 to ±0.38 arc seconds (depending on ring diameter)

±4.20 to ±0.40 arc seconds (depending on ring diameter)

Maximum speed

4 400 rpm (for 52 mm diameter ring)

(See data sheet for details)

Sub-Divisional Error (SDE)

Ring diameters ≤ 135 mm, typically < ±20 nm

Ring diameters > 135 mm, typically < ±15 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 across a range of operating conditions

Incremental signals

5 μm to 2.5 nm resolution

(See data sheet for details of angular resolutions)

Electrical connection

0.2 m, 0.5 m, 1 m, 1.5 m, 2 m and 3 m cable lengths with D-type connectors (9 and 15 pin), circular in-line connector (12 pin) or 14-way JST connector

Power supply

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

Vibration (operating)

100 m/s2 max @ 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



* System accuracy is graduation error plus SDE. Graduation accuracy is the maximum difference between the angle measured by a single readhead and the true rotation of the encoder as graduated. Application disturbances such as eccentricity are not included.

** < ±10 nm SDE can be achieved with optimised set-up. Please contact your local Renishaw representative for more details.

Refer to data sheets for full details.