Prokit's Industries MT-4012 - Manual (Page 6)

7. Distance to Spot Ratio
The thermometer has an optical angle and spot
size as shown below.
Object Focus tube Sensor
The target should be larger than the unit’s optical
spot size. The distance to spot ratio for this
thermometer is 12:1 (12mm spot at 1meter) as
shown below.
8. Emissivity
Emissivity is a term used to describe the energy
emitting characteristics of a material. The higher
the emissivity value a material has, the more
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infrared energy it will emit at a particular
temperature. And the meter’s emissivity is more
close to the material’s emissivity, the more
particular measurement result you can get. So, it
is important to set a just emissivity according to
the material.
1. Model A and model C have a fixed
(non-adjustable) emissivity of 0.95. Most organic
materials and oxidized metal range in emissivity
between 0.85 and 0.98.
2. Model B has an adjustable emissivity from
0.10 to 1.00. For different materials, you can set
a different emissivity. An object’s emissivity is
relative to its material, finish, color and
temperature etc. The attached sheet is the
emissivity of different substances in the normal
temperature.
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