Thermosight HT
7
Parameter description / adjustments
7.1
EMI (emissivity
ε
)
For a correct measurement it is necessary to adjust the emissivity. This
emissivity
is the relation-
ship between the emission of an real object and the emission of a black body radiation source (this
is an object which absorbs all incoming rays and has an emissivity of 100%) at the same tempera-
ture. Different materials have different emissivities ranging between 0% and 100% (settings at the
pyrometer between 10 and 100%). Additionally the emissivity is depending on the surface condition
of the material, the spectral range of the pyrometer and the measuring temperature. The emissivity
setting of the pyrometer has to be adjusted accordingly. Typical emissivity values of various com-
mon materials for the spectral range of the
THERMOSIGHT HT
are listed below. The tolerance of
the emissivity values for each material is mainly dependent on the surface conditions. Rough sur-
faces have higher emissivities.
Measuring object
EMI (1.45...1.8 µm)
„Black body furnace“
1
Steel heavily scaled
0.85 ... 0.9
Steel rolling skin
0.8 ... 0.88
Steel, molten
0.2 ... 0.25
Slag
0.8 ... 0.85
Aluminum, bright
0.1
Chromium, bright
0.25 ... 0.3
Brass oxidized
0.6 ... 0.7
Bronze, bright
0.03
Copper, oxidized
0.7 ... 0.85
Measuring object
EMI (1.45...1.8 µm)
Zinc
0.45 ... 0.55
Nickel
0.15 ... 0.2
Gold, Silver, bright
0.02
Porcelain glazed
0.6
Porcelain rough
0.8 ... 0.9
Graphite
0.8 ... 0.9
Fireclay
0.45 ... 0.6
Stoneware, glazed
0.8 ... 0.9
Brick
0.8 ... 0.9
Soot
0.95
7.2
MAX (maximum value)
The MAX function shows the highest reading taken during a measurement.
This feature is particularly useful for applications with fluctuating object temperatures or for the
measurement of moving objects which are not constantly in the measuring beam of the pyrometer.
With every new measurement the maximum value storage is cleared automatically, i.e. pushing the
trigger again.
Note:
The response time of the pyrometer and with that the maximum value
storage function is faster than the update of the display.
7.3
MIN (minimum value)
The MIN function shows the lowest reading taken during a measurement.
Note:
The response time of the pyrometer and with that the minimum value
storage function is faster than the update of the display.
7.4
AVG (average function)
The average function always shows the average of the readings of the last 4 seconds.
7.5
DIF (difference temperature function)
If the DIF function is activated, a start temperature value is stored by pushing the trigger and the
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