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Measurement Preparations
Setting the emissivity for surface temperature
measurements
The emissivity of an object depends on the material and the
structure of its surface. This specifies how much infrared
thermal radiation the object emits compared with an ideal
radiant warmer (black body, emissivity ε = 1) and accord-
ingly has a value between 0 and 1.
To determine the surface temperature, the tool performs a
contactless measurement of the natural infrared thermal ra-
diation emitted by the object at which the tool is aimed. To
ensure correct measurement, the emissivity setting on the
measuring tool must be checked before every measure-
ment and adapted to the measuring object if necessary.
The preset emissivities in the measuring tool are reference
values.
You can select one of the preset emissivities or enter an ex-
act numerical value. Set the required emissivity via the
<Measurement> → <Emissivity> menu (see "Main Menu",
page 11).
Temperature measurements will only be correct if the
u
emissivity setting and the emissivity of the object
match.
The lower the emissivity, the greater the effect of the reflec-
ted temperature on the measuring result. Always adjust the
reflected temperature when changing the emissivity. Set the
reflected temperature via the <Measurement> →
<Reflected Temp.> menu (see "Main Menu", page 11).
Temperature differences allegedly shown by the measuring
tool may be caused by different temperatures and/or differ-
ent emissivity levels. If the emissivity levels are very differ-
ent, the depicted temperature differences may differ consid-
erably from the actual temperature differences.
If there are multiple objects made of different materials or
that have different structures in the measuring range, the
displayed temperature values are only accurate for the ob-
jects that match the emissivity setting. For all other objects
(with different emissivity levels), the displayed colour differ-
ences can be used as an indication of temperature relation-
ships.
Information about the Measuring Conditions
Highly reflective or shiny surfaces (e.g. shiny tiles or pol-
ished metals) may significantly distort or impair the results
shown. If necessary, mask the measuring surface with a
dark, matt adhesive tape that conducts heat well. Allow the
tape to briefly reach the correct temperature on the surface.
Make sure that a favourable measuring angle is used on re-
flective surfaces in order to ensure that the thermal radiation
reflected by other objects does not distort the result. For ex-
ample, the reflection of your own emitted body heat may in-
terfere with the measurement when measuring head-on from
a perpendicular position. On a level surface, the outline and
temperature of your body could therefore be displayed (re-
flected value), and these values do not correspond to the ac-
tual temperature of the measured surface (emitted value or
real value of the surface).
Bosch Power Tools
Measuring through transparent materials (e.g. glass or trans-
parent plastics) is fundamentally not possible.
Consequently, the more suitable and stable the measuring
conditions are, the more accurate and reliable the measure-
ment readings are. Not only do significant fluctuations in the
temperature of the environmental conditions have an im-
pact, the accuracy can also be impaired by significant fluctu-
ations in the temperatures of the object being measured.
Infrared temperature measurement is impaired by smoke,
steam/high humidity or dusty air.
Information for achieving improved measurement accuracy:
– Move as close as possible to the object to be measured to
minimise interfering factors between you and the surface
to be measured.
– Ventilate indoor areas prior to measurement, especially
when the air is contaminated or extremely steamy. Once
ventilated, allow the room to reacclimatise a while until it
returns to the usual temperature.
Assigning Temperatures on the Basis of the Scale
The scale (h) is shown on the right-hand side of
the display. The values at the top and bottom end
are oriented to the maximum temperature (g)
and minimum temperature (i) recorded in the
thermal image. For the scale, 99.9 % of the total
pixels are evaluated. Colours are assigned to
temperature values with a uniform distribution in
the image (linearly).
Different shades can therefore be used to assign
temperatures within these two limit values. For
example, a temperature that is exactly between
the maximum and minimum value is assigned to
the centre colour range of the scale.
To determine the temperature of a specific area, move the
measuring tool so that the crosshairs with temperature
display (l) are aimed at the required point or area. In the
automatic setting, the colour spectrum of the scale is always
distributed linearly (= uniformly) across the entire measur-
ing range between the maximum and minimum temperat-
ures.
The measuring tool displays all measured temperatures in
the measuring range in relation to one another. If heat is dis-
played as blue in the colour palette in an area, for example in
a colour representation, this means that the blue areas are
among the colder measured values in the current measuring
range. However, these areas may still be in a temperature
range which could cause injuries in certain circumstances.
You should therefore always note the temperatures dis-
played on the scale or at the crosshairs themselves.
Functions
Adjusting the Colour Display
Depending on the measurement conditions, different colour
palettes may make it easier to analyse the thermal image and
English | 9
1 609 92A 58Z | (22.02.2021)
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