VIONiC™ incremental encoder system with RELM20 linear scale
- Digital output direct from the readhead
- Readhead size: 35 x 13.5 x 10 mm
- Resolutions to 2.5 nm*
- Speed up to 12 m/s
- Ultra-low Sub-Divisional Error (SDE): typically <±15 nm*
- Optical IN‑TRAC™ reference mark
- Dual limits
- No separate interface required
- Advanced Diagnostic Tool for easy fault finding, challenging installations and servicing
- Very high accuracy combined with near zero thermal expansion
- High dirt immunity
What is VIONiC?
The VIONiC readhead combines Renishaw's market proven filtering optics and advanced interpolation into one digital incremental encoder with ultra-high accuracy.
The VIONiC encoder system offers a wide variety of speed and resolution configurations, and an expansive range of linear or rotary scale options. This makes it one of the most versatile encoder for high precision feedback. Designed with intuitive auto-calibration mode, VIONiC readheads are also easy to install.
What is new?
*The VIONiC encoder system is now available in resolutions down to 2.5 nm with enhanced SDE across the product range.
What is RELM20 scale?
RELM20 is a spar scale manufactured from ZeroMet™, a low expansion nickel/iron alloy, featuring 20 µm pitch incremental graduations.
It is comparable to fine pitch glass scales and offers a total accuracy (including slope and linearity) better than ±1.5 µm over a 1.5 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?
All purpose digital encoder system
VIONiC is the encoder of choice because it combines high speed interpolation with impressive metrology performance making it suitable for even the most demanding applications. A wide range of encoder configurations are available so that the user can optimise the speed and resolution of their system depending on their motion control requirements. Furthermore the VIONiC readhead works with both linear and rotary scales across a range of accuracies. The VIONiC encoder is quick and easy to calibrate, meaning it is suitable for volume production.
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.
Ease of handling
The RELM20 ZeroMet low thermal expansion scale has a much smaller cross section than typical glass scales and allows easier handling and installation without risk of breakage, making it ideal for the most demanding precision applications.
Optional 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
RELM20: high accuracy ZeroMet spar scale with mid reference mark
Also available with end reference mark as RELE20
Readhead size (LxWxH)
35 mm x 13.5 mm x 10 mm
Coefficient of thermal expansion at 20 °C
0.75 ±0.35 μm/m/°C
Accuracy grade at 20 °C
Certified to ±1 μm per m, calibration traceable to International Standards
IN-TRAC reference mark
Various reference mark position options, see data sheet for details
20 mm to 1 500 mm
Up to 12 m/s
(See data sheet for details)
Sub-Divisional Error (SDE)
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
5 μm to 2.5 nm resolution
(See data sheet for details)
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)
5 V -5%/+10%, typically <200 mA fully terminated
100 m/s2 max @ 55 Hz to 2 000 Hz
500 m/s2, 11 ms, ½ sine, 3 axes
Operating temperature (system)
0 °C to +70 °C
* <±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.
How it works
The VIONiC encoder 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 <±15 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.
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.