Mercury II 6000 Vacuum Encoder

The new Mercury II™ 6000 series of micro encoders from MicroE Systems

Posted Date: 01st Oct 2011

Inmoco has launched a new version of its new Mercury II™ 6000 series of micro encoders from MicroE Systems, for use in vacuum environments. The new encoder is rated to 10-8 torr vacuum, and bake out at 150°C for 48 hours. In common with other encoders in the Mercury II™ 6000 series, it enables OEMs and users to reduce both system size and cost. The encoder’s sensor height is half the size of competitive encoders, making it easier to fit into system designs. This reduction can also cut motion system weight and cost by allowing the use of smaller motors and stages.

Offering High-speed operation - up to 5m/s at 0.1μm output resolution, the Mercury II 6000 vacuum encoder sets new benchmarks for sensor size, resolution and accuracy. The sensor is only 8.2mm high, weights just 3 grams and provides output resolution as precise as 1.2 nanometers. These features, plus the flexibility for use with linear or rotary scales with built-in index and limits, make the Mercury II 6000 series ideal for use in demanding applications such as microscopy, life sciences, automated optical inspection, semiconductor processing, metrology, and many more.

Designed for both linear and rotary applications, Mercury II 6000's exceptional cyclical error (short-travel accuracy) of ±20 nanometers delivers the precise nano-positioning feedback and smooth velocity control of fine pitch encoders costing 2-3 times more. Linear glass scales provide uniform thermal behaviour and accuracy up to ±1µm. In addition, low heat generation at the sensor minimises errors and distortions due to thermal effects, resulting in high signal stability and up to ±1.2nm of repeatability. Key to attaining this performance is low jitter – essential for nanometer applications – which is achieved by a combination of optical design, signal processing electronics and a user-programmable low pass output filter.

The Mercury II 6000 Series is adaptable to the widest range of application requirements: output resolution is user programmable, ranging from 5µm to 1.2nm, linear, and high speed applications are supported by the fastest A-quad-B output in the 20µm encoder class, providing up to 1m/s at 20nm resolution. In addition, optional serial word output increases encoder speed capability to 10m/s at 1.2nm resolution.

The simplicity of the Mercury II 6000 design enables fast setup to be achieved with minimal skill. Key to this operation is Mercury II's optical system, which features the broadest alignment tolerances of any 20µm-pitch encoder - particularly in the Theta Z axis. Rotational tolerance about this axis is ±2° - fully 300% better than the next best competitive encoder - and ride height tolerance is ±0.15mm.

In addition to the vacuum encoder, the Mercury II 6000 series includes two additional units, all with low heat generation at the sensor: 50mA @ 5VDC - a fraction of other encoders in this resolution class. Version 1 is supplied with digital outputs for A-quad-B, index, dual limits and alarm. Version 2 is the Mercury II 6800Si, with high speed serial output in SPI format for servo control at speeds up to 10m/s with 1.2nm resolution.