TONiC™ UHV incremental encoder system with RELM20 linear scale
Features
- 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
- Optical IN-TRAC™ reference mark
Benefits
- Ultra-High Vacuum (UHV)
- Very high accuracy combined with near zero thermal expansion
- Super-compact encoder with dynamic signal conditioning for improved motion control
- Diagnostic kit to assist challenging installations and aid system optimisation

What is TONiC UHV?
TONiC UHV brings Renishaw's super-compact, non-contact encoder system to Ultra-High Vacuum applications offering customers improved motion control.
TONiC offers speeds up to 10 m/s and, 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 RELM20 scale?
RELM20 is a spar scale manufactured from ZeroMet™, a low expansion nickel/iron alloy, featuring a 20 µm pitch.
It is comparable to fine pitch glass scales and offers a total accuracy (including slope and linearity) better than ±1 µm over a 1.5 m length. ZeroMet has a coefficient of thermal expansion of 0.75 ±0.35 μm/m/°C at 20 °C.
System designers can choose between specially formulated UHV compatible 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?
Ultra-High Vacuum (UHV)
TONiC UHV readheads take standard TONiC outstanding performance and deliver it in a readhead that has been designed and constructed using UHV compatible materials and processes making it suitable for UHV conditions down to 10 -10 Torr.
The range of TONiC UHV encoders and accessories are constructed from vacuum-compatible materials and adhesives to give low outgassing rates and proven clean residual gas analysis (RGA) making them suitable for many applications including wafer handling / testing, scientific instruments, spectroscopy, vacuum inspection equipment and many more.
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.
Ultimate reliability and performance in a compact size
For ultimate reliability and consistent performance 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 just ±30 nm. The result is smoother velocity control for improved scanning performance, increased positional stability which in turn helps minimise the heat build-up in motors inside the vacuum; essential parameters for vacuum applications all in a compact readhead.
Vacuum and Functional Safety variants
The TONiC encoder offers a single solution regardless of the application, with the same exceptional metrology capability offered by TONiCUHV, for Ultra-High Vacuum applications, and TONiC FS, for systems requiring Functional Safety certification to SiL2 and PLd.
Interface options
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.
Technical specifications
Measuring standard | 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 |
Scale pitch | 20 μm |
Coefficient of thermal expansion at 20 °C | 0.75 ±0.35 μm/m/°C |
Accuracy grade at 20 °C | Certified to ±1 μm, calibration traceable to international standards |
Reference mark | IN-TRAC reference mark Various reference mark position options, see data sheet for details |
Limit switches | Dual or single limits (select at time of order) |
Scale length | 20 mm to 1.5 m |
Maximum speed Analogue Digital | (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 |
Incremental signals Analogue Digital | 1 Vpp (20 μm period) Resolutions from 5 μm to 1 nm |
Electrical connection | 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) |
Power supply | 5 V ±10%, < 100 mA (analogue system), < 200 mA (digital systems) (unterminated) |
Readhead power consumption | < 100 mA |
Vibration (operating) | 100 m/s2 max @ 55 Hz to 2 000 Hz |
Shock (non-operating) | 1 000 m/s2, 6 ms, ½ sine |
Operating temperature (system) | 0 °C to +70 °C |
Bake-out temperature (non-operating) | 120 °C (Readhead and scale only) |
Sealing | Readhead: IP20 Interface: IP20 |
Cable construction | Tinned copper braided single screen, FEP core insulation |
Refer to data sheets for full details.