Mask a position sensor’s data bits to reduce resolution

Used In:

  • Sensors with resolutions of over 32 bits
  • Reducing sensor sensitivity for certain applications
  • Reducing the absolute reading range for certain applications

Description

Elmo’s Gold drive supports reading of up to 32 bits of position data from an encoder. To support sensors with data resolutions greater than 32 bits (or over 30 bits per rotary revolution), the user can mask low and/or high bits to reduce the data resolution as required.

When low bits are masked, sensor sensitivity is reduced. When high bits are masked, absolute sensing range is reduced, making it possible that the same point might be reported at more than one position.

For example: with a linear absolute sensor providing 36 bits of position data at a resolution of 1 nanometer, the user needs to mask at least 4 bits in order to limit the total to 32 bits of position data.

  • For each low bit that is masked, sensor resolution will be reduced by a factor of 2. Masking 4 low bits reduces resolution by 16 (24).
  • For each high bit that is masked, the range of position reports will be smaller by a factor of 2. Masking the 4 high bits makes the range smaller by 16 (24).

Design Features

  • Sensor position data resolution can be defined in software
  • High bit masks for sensor data can be defined