Accounting For Emissivity - General IRT105 Manual Del Usuario

IRT105 Manual FINAL-070111_Layout 1 7/1/11 2:53 PM Page 11
to appear blinking on the top line of the display. Unlike in
other modes, the blinking icon indicates that a new mode
has already been entered—in this case, Emissivity
Selection mode.
The factory-set default emissivity value of the IRT105 is
0.95. To enter the emissivity value of your target surface
material:
• Locate the material in Table 1 in the shaded box,

Accounting for Emissivity.

• Press the Meas. (measure) button as many times as
necessary to change the display from the factory-set
default value of 0.95 to the desired value. Note that each
press of the button increases the displayed value by
0.01. After five presses, starting at 0.95, the displayed
value will be 1.00. The next press will change the value
to 0.10—the lowest possible emissivity setting. Each
subsequent press of the Meas. (measure) button will
increase the value by 0.01 units.
• When you have reached the desired emissivity value,
press the Mode button to store the setting. The IRT105
will use this value in its temperature calculations until
you change it.
ACCOUNTING FOR EMISSIVITY
Emissivity is the ability of an object to reflect or absorb
IR radiation (energy). Because the IRT105 measures the
amount of infrared energy emitted by a surface, the IRT's
measurements are most accurate when they take into
account the characteristic emissivity of the target material.
A perfectly absorbent surface (called a black body) has an
emissivity (represented by the Greek letter ) of 1; it
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