LumaSense Technologies IN 2000 - Handbuch (Seite 9)

IMPAC Infrared sensor IN 2000
9
7.2
Basic range
Basic range displays the total range of the pyrometer automatically and can not be changed.
7.3
Material
Under Material you have the possibility to store the names of different measuring objects with their emissivity
values and to recall them from the list. Additionally the material entrances can be done in the text file
„mat.txt.“ (provided in the folder „InfraWin“ in the standard "Documents and Settings "path of Windows,
normally C:\ Documents and Settings \ <user name> \ InfraWin).
7.4
Emissivity ε
For a correct measurement it is necessary to adjust the emissivity. This emissivity is the relationship between
the emission of a real object and the emission of a black body radiation source (this is an object which ab-
sorbs all incoming rays and has an emissivity of 100%) at the same temperature. 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 ac-
cordingly. Typical emissivity values of various common materials for the two spectral ranges of the instru-
ments are listed below. The tolerance of the emissivity values for each material is mainly dependent on the
surface conditions. Rough surfaces have higher emissivities.
Measuring object
ε (at 8 ... 14 µm) Measuring object ε (at 8 ... 14 µm)
"Black body furnace" 100% Brickwork
Human skin 98% Fire clay
Black dull varnish 95% Rubber
Carbon soot 95% Porcelain
Wood 80 to 92% Ceramics
Paper 92 to 95% Varnish
Asphalt 85% Plaster
Glass / quartz glass 72 to 87% Oil paint
85 to 95%
Textile 75 to 95% Steel (oxidized) 60 to 80%
Graphite 75 to 92% Steel (smooth) 10 to 30%
Cement 90% Aluminum (smooth) 2 to 15%
Water 95% Aluminum (anodized) 90%
7.5
Response time / exposure time (t90)
The exposure time is the time interval when the measured temperature has to be pre-
sent after an abrupt change so that the output value of the pyrometer reaches a given
measurement value. The time taken is to reach 90% of the recorded temperature differ-
ence. In the “min” position, the device operates using its time constant.
Longer exposure times can be used for the measurement of objects which have rapidly
fluctuating temperatures to achieve constant temperature reading.
7.6
Transmittance 
Using the close-up lens or measurements through protection windows slightly attenuates the measuring
signal (due to the transmittance). To get furthermore correct measuring results, the transmission of this
window (with a ZnSe window standard is 72%) must be compensated. Alternatively the emissivity ε can be
adapted (ε
Trans
= transmittance x ε
Object
)
Settings:
min
0.5 s
1.0 s
. . .
120.00 s