Linear Encoder System offers low thermal expansion.

Press Release Summary:

Made of Invar for thermal expansion of 1.3 µm/m/K, RELM linear scale intelligent encoder offers non-contact performance with accuracy to ±1 µm/m, resolution to 20 nm, and speeds above 10 m/s. System is comprised of SR readhead, Si interface, 20 µm RELM spar in defined lengths, and features such as SiGNUM(TM) intelligent signal processing and IN-TRAC(TM) auto-phase optical reference mark. SiGNUM(TM) software enables set-up and real-time system diagnostics via PC USB port.

Original Press Release:

Newest in Renishaw SiGNUM(TM) Range of Intelligent Encoders - the RELM High Accuracy Linear Scale Made from Invar for Ultra-Low Thermal Expansion

SiGNUM encoders combine proven Renishaw design strengths with higher speeds and operating temperature, ultra-low cyclic error, intelligent signal processing, and IN-TRAC(TM) optical reference mark

July 2005 - The RELM high-accuracy linear scale joins Renishaw's SiGNUM(TM) range of intelligent, high-performance encoders combining accuracy to ±1 µm/m and resolution to 20 nm with speeds above 10 m/s and temperatures to 85°C. Initially available in Invar, which provides a low thermal expansion of 1.3 µm/m/K, the RELM scale offers a choice of IN-TRAC(TM) reference mark positions and dual optical limits. Robust, yet highly precise, the 20 µm spars allow the RELM to offer a level of performance previously available only from more delicate fine-pitch encoder systems. Non-contact performance provides high reliability to satisfy the most demanding precision motion requirements and high throughput manufacturing operations.

The advanced SiGNUM RELM linear encoder system comprises the SR readhead. Si interface, 20 µm RELM spar in defined lengths, and advanced features including IN-TRAC and intelligent signal processing. The IN-TRAC(TM) auto-phase optical reference mark is repeatable in both directions across the entire speed and temperature range.

The SR readhead is sealed to IP64. Like all Renishaw encoders, it benefits from unique filtering optics, which provide excellent immunity to dirt, dust and scratches. The RELM scale is easy to install and can be mounted directly to the substrate using mechanical clips or a specially formulated adhesive backing tape. The Si interface can be mounted remotely and a small connector on the readhead can easily be fed through machines where access is restricted.

As part of the SiGNUM(TM) range, the RELM encoder system benefits from SiGNUM(TM) intelligent signal processing, which ensures excellent reliability and ultra-low cyclic error (typically <±40 nm). In addition, comprehensive SiGNUM(TM) software enables optimum set-up and real-time system diagnostics via a PC's USB port.

As with all Renishaw products, the SiGNUM(TM) range is backed-up by a worldwide team offering truly responsive global support.

For more information on Renishaw's encoders, contact Howard Salt, Business Manager, Encoder systems, Renishaw Inc., 5277 Trillium Boulevard, Hoffman Estates, IL 60192. Phone 847-286-9953; fax 847-286-9974. Email:

For a detailed look at other productivity enhancements for metrology, linear and rotary position feedback, and machine tool calibration, visit Renishaw's web site at:

Reader inquiries should be directed to:
Susan Wilm
Marketing Assistant
Renishaw Inc.
5277 Trillium Boulevard
Hoffman Estates IL 60192

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