Hioki HiTester 3443-01, Instruction Manual

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Chapter 5 Maintenance and Service
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5.2 Questions and Answers about
Measurement
Q: Why can't I measure the temperature on the other
side of a glass pane?
A: Normal glass absorbs infrared radiation of the
wavelength (8 to 16
μ
m) which this device uses for
temperature measurement. Therefore this device
cannot measure the temperature of an object on the
other side of a glass sheet, but instead measures the
temperature of the glass sheet itself.
Q: Light is shining on an object. Why can't I measure
its temperature accurately?
A: Since fluorescent light includes almost no infrared
radiation, it has almost no effect upon normal
temperature measurement. However sunlight and
incandescent lights emit radiation which includes
substantial amounts of the infrared radiation used by
this device for temperature measurement, and
accordingly may produce significant measurement
discrepancies.