Mercury 1500V (M1500V) digital output encoders are rated to 1 X 10- 8 torr of vacuum. The sensor is vented, rated for 48-hr bake out at 150°C, and works with both linear and rotary glass scales. Available resolutions range from 5 to 0.50 m (linear), or 6,600 to 655,000 CPR (rotary). Factory-set interpolation levels are X4, X8, X20, or X40. The sensor, which is 8.4-mm tall and weighs 2.7 gm, directly produces A-quad-B and bidirectional index window digital outputs. Its low Z-height lets the encoder work with motion platform designs in semiconductor-processing equipment, electron microscopy, and other vacuum-rated applications. With an alignment tolerance of ±2°, the sensor aligns in 30 sec or less without instrumentation. The system is EMI shielded against electrical noise and has flying leads for termination at the vacuum wall.

MicroE Systems, 8 Erie Dr., Natick, MA 01760, (508) 903-5000,