RESOLUTE™ ETR absolute encoder system with REXA30 rotary (angle) ring
- Serial interface: BiSS® C
- Readhead size: 36 x 16.5 x 17.2 mm
- Resolutions to 32 bits/rev
- Speed up to 8 500 rpm
- Operating temperature range: -40 °C to +80 °C
- Installed accuracy to ±1 arc second
- Side cable outlet version available
- Thick cross-section ring
- Excellent motion control performance
- Wide set-up tolerances
- Less than 10 nm RMS jitter for improved positional stability
- ±40 nm Sub-Divisional Error for smooth velocity control
- Optional Advanced Diagnostic Tool
What is RESOLUTE ETR?
RESOLUTE ETR (Extended Temperature Range) is a true absolute, fine pitch optical encoder system that has excellent dirt immunity, and an impressive specification that breaks new ground in position feedback. It is the world's first absolute encoder capable of 32-bit resolution at 8 500 rpm.
This brings all the benefits of the revolutionary RESOLUTE absolute, fine pitch angle encoder to harsh, low-temperature applications. With operation guaranteed down to -40 °C (-40 °F) in non-condensing environments, RESOLUTE ETR is ideally suited for use in demanding applications such as telescopes, scientific research and defence and aerospace.
What is REXA30 ring?
REXA30 is a one-piece stainless steel ring with 30 µm pitch absolute graduations marked directly on the periphery. Its larger cross-section allows for the reduction in all installation errors apart from eccentricity, which is easily corrected using the average result of two Resolute readheads. Featuring total installed accuracy up to ±1 arc second, zero coupling losses, and exceptional repeatability.
REXA30 is available in a range of sizes (Ø52 mm to Ø417 mm), 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?
Easy fault finding and servicing
The Advanced Diagnostic Tool ADTa‑100 acquires comprehensive real-time data from RESOLUTE™ encoder readheads (marked with the ADT symbol). The information is displayed via the user-friendly ADT View software interface. Whilst in most cases the integral set-up LED on the encoder is sufficient for setting up the system, the ADT can be used to aid more challenging installations. The ADT can also report on encoder performance and assist system fault finding to avoid lengthy machine downtime.
ETR (Extended Temperature Range)
With solid stainless steel scales and high vibration resistance, the RESOLUTE ETR absolute encoder has been designed to withstand the physical punishment of harsh environments, yet still offer outstanding metrology, exceptionally high speeds and excellent reliability on rotary axes.
Wide set-up tolerances
RESOLUTE does not follow the conventional technique of using dual tracks side-by-side (one incremental, one absolute) which inherently suffers de-phasing problems when small amounts of angular misalignment are introduced. Instead, this absolute encoder features a single track, optical absolute scale, combining both the absolute position and embedded phase information into one single code. This technology provides RESOLUTE with far wider set-up tolerances (yaw tolerance ±0.5°) for quick and easy installation and superior long-term reliability, even if the motion axes settle or move over time. To further aid installation and diagnostics, there is an integral set-up LED on the readhead.
Optional Advanced Diagnostic Tool ADTa-100
RESOLUTE encoder readheads (marked with the ADT symbol) are compatible with the Advanced Diagnostic Tool ADTa-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
- Digital readout of encoder position (relative to the scale)
- Exporting and saving data
- Setting zero
Renishaw supports BiSS C (unidirectional) open protocol for absolute encoders. BiSS C is a high-speed serial interface, perfect for dynamic axes that require high acceleration, silky-smooth velocity control, excellent repeatability and rock-solid positional stability.
One-piece ultra high accuracy absolute coded stainless steel ring
Readhead size (LxWxH)
36 mm x 16.5 mm x 17.2 mm
Nominal 30 μm
|Coefficient of thermal expansion at 20 °C
|15.5 ±0.5 μm/m/°C
Ring outer diameter
52 mm to 417 mm
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)
8 500 rpm (on 52 mm ring)
BiSS C: 18-bit, 26-bit and 32-bit
Sub-Divisional Error (SDE)
0.5 m to 10 m cable lengths with D-type connectors (9 pin or 15 pin), flying lead
5 V ±10%, 250 mA @ 5 V (terminated)
300 m/s2 max @ 55 Hz to 2 000 Hz
1 000 m/s2, 6 ms, ½ sine
-40 °C to +80 °C
Refer to data sheets for full details.
†Other serial interfaces are continually being added.