TONiC™ incremental encoder system with RSLM20 linear scale
- Readhead size: 35 x 13.5 x 10 mm
- Resolutions to 1 nm
- Speed up to 10 m/s
- Analogue or digital outputs
- Ultra-low Sub-Divisional Error (SDE): typically <±30 nm
- Vacuum compatible version available
- Optical IN-TRAC™ reference mark
- High accuracy spar scale
- Super-compact encoder with dynamic signal conditioning for improved motion control
- High dirt immunity
- Diagnostic kit to assist challenging installations and aid system optimisation
What is TONiC?
TONiC is Renishaw's super-compact, non-contact encoder system that offers speeds up to 10 m/s and, when combined with the Ti interface, resolutions down to 1 nm for both linear and rotary applications. TONiC systems are quick and simple to install with wide set-up tolerances and calibration at the push of a button. TONiC's dynamic signal processing gives improved signal stability with ultra-low Sub-Divisional Error of typically <±30 nm to help realise superior motion control performance.
What is RSLM20 scale?
RSLM20 is a stainless steel spar scale featuring 20 µm pitch and a variety of IN-TRAC optical reference mark options, including regularly spaced for customer selection or single reference at the centre or close to the end.
It is comparable to fine pitch glass scales and offers a total accuracy (including slope and linearity) better than ±4 µm over a 5 m length. It can also be coiled for simple storage and handling yet once uncoiled behaves as a spar scale.
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?
Combines rugged reliability with higher accuracy
The TONiC RSLM20 system offers the convenience, ruggedness and ease of use of a tape scale yet offers a higher accuracy than glass scales making it ideal for long length, high performance axes.
Ultimate reliability and performance in a compact size
For ultimate reliability, consistent performance and high dirt immunity, TONiC readheads incorporate third-generation filtering optics, tuned for even lower noise (jitter) and now further enhanced by dynamic signal processing including Auto Gain Control and Auto Offset Control. This combination – all incorporated inside the readhead - provides signals of unrivalled purity and ultra-low Sub-Divisional Error of typically <±30 nm. The result is smoother velocity control for improved scanning performance and increased positional stability; essential parameters for so many applications, all in a compact readhead.
Quicker and easier installation
A set-up LED on the readhead gives a visual indication of signal size and an optional diagnostic kit allows remote checking of the system performance when the readhead is concealed within the machine. Calibration of the reference mark and incremental signals is done at the push of a button with no mechanical adjustment or additional diagnostic tools. The IN-TRAC customer-selectable optical reference mark is embedded in the incremental scale for compact dimensions and simplified alignment. This yields a reference mark output that is bi-directionally repeatable to unit of resolution over the full operating temperature and speed range.
TD (dual resolution) interface
- Selectable dual-resolutions quadrature output.
- Ideal for applications that require high speed movement combined with finer precision motion.
DOP (dual output) interface
- Provides simultaneous digital quadrature and 1 Vpp signals.
- Designed for applications requiring one or more operations to be synchronised with a motion axis.
Optional diagnostic kit
TONiC diagnostic software can be used to optimise the installation of TONiC encoders and provide a quick and comprehensive system calibration. The software must be used in conjunction with the TONiC diagnostic hardware which can be purchased from Renishaw using part number A-9411-0011. The hardware is connected to the PC via the USB cable (provided in the kit) or in-line with the customers' electronics.
Find out all about the TONiC diagnostic kit.
RSLM20: high accuracy stainless steel spar scale
Also available with end reference mark as RSLE20, and with selectable reference mark as RSLC20
Readhead size (LxWxH)
35 mm x 13.5 mm x 10 mm
Coefficient of thermal expansion at 20 °C
10.1 ±0.2 μm/m/°C
Accuracy grade at 20 °C
±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, calibration traceable to International Standards
IN-TRAC reference mark
Various reference mark position options, see data sheet for details
Dual or single limits (select at time of order)
80 mm to 5 000 mm
(See data sheet for details)
Up to 10 m/s at -3 dB
Up to 10 m/s
Sub-Divisional Error (SDE)
Typically <±30 nm
Dynamic signal control
Real time signal conditioning including Auto Gain Control (AGC) and Auto Offset Control (AOC) for optimised performance during operation
1 Vpp (20 μm period)
Resolutions from 5 μm to 1 nm
0.5 m, 1 m, 1.5 m, 3 m, 5 m and 10 m cable lengths with mini connector (connects direct to TONiC interface)
5 V ±10%, <100 mA (analogue system), <200 mA (digital systems) (unterminated)
100 m/s2 max @ 55 Hz to 2 000 Hz
1 000 m/s2, 6 ms, ½ sine
Operating temperature (system)
0 °C to +70 °C
Refer to data sheets for full details.
How it works
TONiC 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 <±30 nm.
This evolution of filtering optics, combined with carefully-selected electronics, provide incremental signals with wide bandwidth achieving a maximum speed of 10 m/s with the lowest positional jitter (noise) of any encoder in its class. Interpolation is by CORDIC algorithm within the TONiC Ti interface, with fine resolution versions being further augmented by additional noise-reducing electronics to achieve jitter of just 0.5 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. Yielding a reference mark output that is bi-directionally repeatable to unit of resolution at all speeds. This unique arrangement also benefits from an automatic calibration routine that electronically phases the reference mark and optimises the dynamic signal conditioning