Performance
  Excess Gain
    Air Environment
    Poorly Reflective Surfaces
      Material Distinction
  Beam Diameter

Geometry
  Line Of Sight
  Object Size
  Proximity To Sensor
    Touch For Detection
    Minimum Distance
    Maximum Distance
  Mounting
    Through Barrier
    Space

Environment
  Temperature
  Power Supply
    Ac
      12VAC
      24VAC
      120VAC-60HZ
      120VAC
      230VAC
    Dc
      12VDC
      24VDC
      11-28VDC

Load
  Current
    Minimum Current
    Maximum Current
  Response Time

Temperature

If a self-contained control is not able to handle a needed operating environment temperature, a modular unit may be used instead.