LumaSMART
®
User Manual
Introduction
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15
spectrum in the near infrared region. The time required for the phosphorescence to decay is dependent upon the
phosphor temperature.
After the LED is turned off, the decaying phosphorescent signal continues to transmit through the fiber to the
instrument, where it is focused onto a detector. After the LED is turned off, the return signal is amplified and
sampled. The measured decay time is then converted to temperature, using the built-in DSP.
2.2.2
Extracting Temperature from Phosphorescent Decay Time
The figure below illustrates the method used to extract the phosphor sensor phosphorescent decay time constant
(
). A mathematical curve fit correlates individual data points with stored values of (
). The measured value of (
)
is then conditioned using the values in an internal calibration table to determine temperature.
Plot Representation of Method for Extracting Decay Time
2.3
System Components
2.3.1
LumaSMART
®
Controller
LumaSMART’s flexible design enables sophisticated temperature control of the transformer without the need for
additional instruments. One of the primary design features of the LumaSMART controller is reliability. The system
utilizes all solid-state light sources, an LCD display, and a touch screen designed to withstand years of use. In
addition, the controller can be wall or panel mounted or in a NEMA 4X enclosure.
