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Renishaw, a provider of measurement and encoder technology, has introduced Resolute: a true absolute, fine-pitch optical encoder system.

According to the company, the system features dirt immunity and a specification in position feedback.

Resolute is capable of 27-bit resolution at 36,000 revolutions per minute.

It has a resolution of 1nm at up to 100m/s for both linear and angle encoding applications.

The system reads a single-track optical scale and offers further benefits to machine designers by acquiring absolute position immediately upon switch-on, without the need for battery back-up.

This eliminates the need for reference returns.

Combinations of ruggedness, ultra-high speed and resolution mean that Resolute is suitable for manufacturers of high-performance lathes and slower-moving axes requiring high levels of precision and motion-control integrity.

The Resolute absolute encoder uses new optics to read the fine-pitch 30-micron scale with low-noise levels (jitter of less than 10nm RMS) for positional stability, while the enhanced detection method intrinsically provides a very low sub-divisional error (SDE) of +/-40nm.

The company claims that the result is better surface finish of machined parts from CNC machine tools, better scanning and velocity control and solid servo stiffness on linear motors or rotary direct drives when holding position.

Resolute does not follow the conventional technique of using dual tracks side by side (one incremental, one absolute), which inherently suffer 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 is intended to provide Resolute with wider setup tolerances for installation and long-term reliability, even if the motion axes settle or move over time.

To further aid installation and diagnostics, there is an integral setup light-emitting diode (LED) on the readhead.

The linear encoder version of Resolute is available with a range of scale options.

RELA Invar spars offer zero expansion and +/-1-micron accuracy on lengths up to 1m.

For high performance on long axes and more robustness than glass scales, RSLA stainless-steel spars have a total accuracy of +/-4 microns over 5m.

Additionally, installation is facilitated by the Fastrack and RTLA tape scale with accuracy of +/-5 microns per metre.

RESA rings are bolt-hole compatible with Renishaw’s Signum RESM rings and are offered in a standard range of diameters from 52mm to 550mm, with even larger size options available to order.

As with the Signum RESM, RESA rings feature large through-holes for design-in and a patented taper mount to facilitate adjustment of eccentricity, while minimising shaft preparation costs.

Reliability is said to be assured with Resolute’s IP64-sealed readhead with wipe-clean recovery.

The precision optics provide immunity to dirt on the scale, which is further enhanced by extensive redundancy in the scale code.

Safety is assured by a built-in separate and independent position-checking algorithm.

This actively checks every reading, ensuring that any potential problem is flagged long before it reaches the controller.

The readhead also incorporates a temperature sensor to measure heat build-up, giving extra system protection by signalling an alarm condition if the head temperature rises higher than +80C.

This alarm is in addition to the signal monitoring, position checking and speed monitoring that is continuously carried out inside the readhead.

The Resolute absolute encoder uses serial communication for noise immunity.

It is available with a variety of protocols to simplify connection to a range of industry-standard controllers.

Additionally, it satisfies environmental standards and is WEEE and RoHS compliant.

Renishaw

A world leader in engineering technologies, Renishaw’s core skills in measurement and precision machining serve sectors as diverse as dimensional metrology, spectroscopy, machine calibration, motion control, dentistry and surgical robotics.

A world leader in engineering technologies, Renishaw’s core skills in measurement and precision machining serve sectors as diverse as dimensional metrology, spectroscopy, machine calibration, motion control, dentistry and surgical robotics.

Sensors for co-ordinate measuring machines (CMMs) are an industry standard, from basic touch-trigger probes through to automated stylus and probe changers, motorised indexing probe heads, and revolutionary five-axis measurement systems.

Machine probes for CNC machine tools allow automated tool setting, workpiece set-up, in-cycle gauging and part inspection. Products include laser tool setters, contact tool setters, tool breakage detectors, touch probes and high accuracy inspection probes.

For motion control, Renishaw supplies laser encoders, optical linear encoders, optical angle encoders, optical rotary encoders, magnetic rotary encoders, magnetic chip encoders and magnetic linear encoders.

To analyse the static and dynamic performance of position-critical motion systems, Renishaw’s laser interferometer and environmental compensation system offers a linear measurement accuracy of 0.5 ppm, readings of up to 50 kHz and a linear measurement speed of up to 4 m/s, with a linear resolution of 1nm.

Renishaw’s Raman spectroscopy products exploit the Raman effect to identify and characterise the chemistry and structure of materials. A diverse range of analytical applications include pharmaceutical, forensic science, nanotechnology, biomedical and semiconductors.

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