TONiC™ incremental encoder system with REXM20 rotary (angle) ring
- Readhead size: 35 x 13.5 x 10 mm
- Resolutions to 1 nm
- Speed up to 3 673 rev/min
- Analogue or digital outputs
- Ultra-low Sub-Divisional Error (SDE): typically <±30 nm
- Vacuum compatible version available
- Optical IN-TRAC™ reference mark
- Thick cross-section ring with installed accuracy of ± 1 arc second
- Super-compact encoder readhead 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 REXM20 ring?
REXM20 is a one-piece stainless steel ring with 20 µm pitch incremental graduations marked directly on the periphery, featuring the IN-TRAC™ optical reference mark. Its larger cross-section allows for the reduction in all installation errors apart from eccentricity, which is easily corrected using a DSi (Dual Signal Interface) and two readheads. Featuring total installed accuracy up to ±1 arc second, zero coupling losses, and exceptional repeatability.
REXM20 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?
Ultra-high installed accuracy
For the ultimate angular metrology, REXM20 with two TONiC readheads and a TONiC DSi (Dual signal interface) offers exceptional repeatability, zero coupling losses and better than ±1 arc second total installed accuracy. The REXM20 features a thicker cross-section designed to minimise all installation errors except eccentricity, which is easily corrected using the combined output of two TONiC readheads. Once the DSi has eliminated eccentricity, the only other errors remaining are graduation and SDE - both of which are minimal.
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 1Vpp signals.
- Designed for applications requiring one or more operations to be synchronised with a motion axis.
DSi (Dual Signal interface)
- Renishaw's DSi combines the incremental signals from two TONiC readheads on a REXM20 ring (REXT20 ring for partial rotation applications) to compensate for the effect of bearing wander and eliminates odd error harmonics, including eccentricity to give total l installed accuracy of typically ±2.0 arc second.
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.
One-piece ultra-high accuracy stainless steel ring
Also available for partial rotation applications as REXT20
Readhead size (LxHxW)
35 mm x 13.5mm x 10mm
|Coefficient of thermal expansion at 20 °C||15.5 ±0.5 μm/m/°C|
Ring outer diameter
52 mm to 417 mm
8 192 to 65 536 (depending on ring size)
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
(See data sheet for details)
3 673 rpm at -3 dB (on 52 mm REXM)
3 673 rpm (5 μm resolution TONiC on 52 mm REXM)
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
(See data sheet for details of angular resolutions)
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 details.
- 3D model: TONiC™ readhead
- 3D model: Ti interface
- 3D model: TONiC™ interboard connector PCB
- 3D model: REXx 52 mm ring
- 3D model: REXx 57 mm ring
- 3D model: REXx 75 mm ring
- 3D model: REXx 100 mm ring
- 3D model: REXx 103 mm ring
- 3D model: REXx 104 mm ring
- 3D model: REXx 115 mm ring
- 3D model: REXx 150 mm ring
- 3D model: REXx 183 mm ring
- 3D model: REXx 200 mm ring
- 3D model: REXx 206 mm ring
- 3D model: REXx 209 mm ring
- 3D model: REXx 229 mm ring
- 3D model: REXx 255 mm ring
- 3D model: REXx 300 mm ring
- 3D model: REXx 350 mm ring
- 3D model: REXx 417 mm ring
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