Selected Measurements
highest precision in environmental conditions
true value (compensation)
measured value w/o (compensation)
constant
environmental conditions
constant
working distance
Displacement measurements as performed at constant
sensor/target separation in variable pressure conditions
(left) and at variable sensor/target separation in constant
environmental conditions (right). The left plot shows
the apparent position change upon pressure variation
(uncompensated 100 ppm, compensated 1 ppm).
The right plot shows the displacement sensing error
of 194 µm over 90 cm travel range (uncompensated)
vs <1 µm (compensated).
Environmental compensation (optional)
Any interferometric device operated in environmental conditions is
negatively influenced by index of refraction fluctuations, caused by
air temperature, pressure, and humidity variation. The influence of
these parameters is significant and can reach deviations in measurement of up to 500 ppm, equivalent to a deviation of 500 µm per meter.
To compensate these errors, attocube offers an environmental
compensation unit (ECU) which precisely measures environmental
parameters and determines the actual index of refraction n(t). This
measurement allows to compensate environmental influences down
to better 1 ppm and enables highly precise, accurate measurements
in air.
(attocube applications labs, 2014)
attoSENSORICS
Ultra Precision Sensors
FPS Sensor
Systems
PAGE 203