Ultra-High Vacuum (UHV) optical encoders
Features
- Constructed from vacuum-compatible materials and adhesives to give low outgassing rates
- Proven clean RGA
- Bake-out temperature to 120 °C
- Non-contact open optical system for high speed, reliable operation with zero friction and zero wear
- No unvented void
- Range of high accuracy linear and rotary scales
There are many industrial processes where the presence of significant amounts of air or other gases would be detrimental to the finished product, and hence must take place in an environment evacuated to very challenging levels of residual pressure. Where these processes involve motion control, vacuum-compatible encoder systems are necessary.
All products in Renishaw's range of Ultra-High Vacuum (UHV) compatible encoders are designed for use in a variety of scientific, semiconductor and other advanced industrial applications with vacuum pressures to 10-10 Torr. The fundamental principles of operation are the same as those for our equivalent standard-atmosphere products, but the UHV variants are designed to eliminate unvented voids and are specially constructed from clean, vacuum-compatible materials and adhesives. The suitability of the products for use in UHV environments is qualified by an independent specialist test house, including a Residual Gas Analysis (RGA) spectrum test (available on request).
UHV absolute encoders
RESOLUTE UHV is the first true-absolute optical encoder for UHV environments and incorporates the same operating principles as the rest of the RESOLUTE range. This provides an encoder with fine-pitch performance and a wide range of serial protocols, combined with wide set-up tolerances and built-in safety. RESOLUTE determines absolute position immediately upon switch-on, eliminating uncontrolled movements and facilitating complete command of axes without the need for reference returns or ‘wake-and-shake'routines. With 1 nm resolution, ±40 nm SDE and <10 nm RMS noise, RESOLUTE also offers users a significant performance upgrade.
UHV incremental encoders
The incremental readheads in the range include dynamic signal conditioning comprising Auto Gain Control (AGC) for solid and dependable signals over extended machine lifetimes, and Auto Offset Control (AOC) for improved signal fidelity. AOC and the encoder's low positional noise also add the benefit of reducing velocity ripple on direct-drive systems, thereby helping minimise heat build-up in motors inside the vacuum. High accuracy is assured, with linear measuring standards including options of self-adhesive tape scale, stainless steel and ZeroMet spars. Angle encoder options include the low-profile RESM and the ultra-high accuracy REXM ring with guaranteed installed accuracy better than ±1 arc second.