Monday, May 21, 2018
Publication Date: 09/1/2010
Archive >  September 2010 Issue >  New Products > 

Fine-Pitch Encoding System from Renishaw
Fine-pitch encoders.
Hoffman Estates, IL — Renishaw's RESOLUTE optical encoder system is being called the world's first true absolute encoder capable of 27-bit resolution at 36,000 rpm. The fine-pitch system offers excellent dirt immunity, while delivering resolution of just 1 nanometer at up to 100m/s, for both linear and angle encoding applications.

Using an unusual single-track optical scale, the encoder acquires absolute position immediately upon switch-on — without battery back-up — simplifying machine design by completely eliminating the need for reference returns. The system's ruggedness, ultra-high speed capability and exceptional resolution make it suitable for high-performance lathes, as well as slower-moving axes requiring the highest levels of precision and motion control integrity. The absolute encoder uses sophisticated new optics to read a fine- pitch, 30-µm scale, resulting in exceptionally low noise levels (jitter <10nm rms) for outstanding positional stability. The enhanced detection technology intrinsically provides a very low sub- divisional error (SDE) of ±40nm. The result is better surface finish of machined parts from CNC machine tools, better scanning and velocity control, and rock-solid servo stiffness on linear motors or rotary direct-drives when holding position.

The encoder's single-track combines both the absolute position and embedded phase information into a single code, eliminating the de- phasing problems that can occur with dual-track scales when small amounts of angular misalignment are introduced. The single-track design allows far wider set-up tolerances for quick and easy installation and superior long-term reliability, even if the motion axes settle or move over time. An integral set-up LED on the readhead further simplifies installation and diagnostics. According to the company, the IP64 sealed readhead permits wipe- clean recovery for outstanding reliability. Precision optics and extensive redundancy in the scale code give excellent immunity to dirt. A built-in, separate and independent position checking algorithm ensures safety by actively checking every reading so 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 signaling an alarm condition if head temperature rises above +80°C. This alarm is in addition to the signal monitoring, position checking and speed monitoring that are carried out constantly inside the readhead.

Contact: Renishaw, Inc., 5277 Trillium Boulevard, Hoffman Estates, IL 60192 847-286-9953 fax: 847-286-9974 E-mail: Web:

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