Switching On And Off; Measurement Preparations - Bosch GTC 400 C Professional Manual Original

Take the batteries out of the measuring tool when you
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are not using it for a prolonged period of time. The bat-
teries can corrode and self-discharge during prolonged
storage in the measuring tool.
Operation with rechargeable battery (see figure C)
Note: The use of batteries unsuitable for your measuring tool
can lead to malfunctions or damage to the measuring tool.
Use only the chargers listed in the technical data. Only
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these chargers are matched to the lithium-ion battery of
your measuring tool.
The lithium-ion battery can be charged at any time without
reducing its service life. Interrupting the charging process
does not damage the battery.
To insert the charged battery pack (23), slide it into the bat-
tery bay (18) until you feel it click into place and it is flush
with the handle of the measuring tool.
To remove the battery pack (23), press the release
buttons (19) and pull the battery pack out of the battery
bay (18). Do not use force to do this.
Operation
Protect the measuring tool from moisture and direct
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sunlight.
Do not expose the measuring tool to any extreme tem-
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peratures or variations in temperature. For example,
do not leave it in a car for extended periods of time. In
case of large variations in temperature, allow the measur-
ing tool to adjust to the ambient temperature before put-
ting it into operation. The precision of the measuring tool
may be compromised if exposed to extreme temperat-
ures or variations in temperature.
Make sure that the measuring tool is correctly accli-
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matised. In case of large variations in temperature, accli-
matisation can take up to 60 minutes. This may be the
case, for example, if you store the measuring tool in a cool
car and then perform a measurement in a warm building.
Avoid hard knocks to the measuring tool or dropping
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it. After severe external influences and in the event of ab-
normalities in the functionality, you should have the
measuring tool checked by an authorised Bosch after-
sales service agent.

Switching On and Off

To take a measurement, fold the protective cap (1) up-
wards. Make sure that the infrared sensor is not closed
off or covered while working.
To switch on the measuring tool, press the on/off
button (9). A start sequence will appear on the display (14).
The measuring tool begins to take measurements as soon as
the start sequence has finished and does so continuously un-
til it is switched off.
Note: In the first few minutes, the measuring tool may self-
calibrate several times, as the sensor temperature and ambi-
ent temperature have not yet been brought into line. Per-
forming sensor calibration again enables precise measure-
Bosch Power Tools
ment.
During this time, the temperature indicator may show ~. The
thermal image will freeze briefly during sensor calibration. If
the ambient temperature fluctuates significantly, this effect
is increased. If possible, you should therefore turn on the
measuring tool a few minutes before starting to measure, so
that the tool can stabilise thermally.
To switch off the measuring tool, press the on/off
button (9) again. The measuring tool saves all settings and
then switches itself off. Close the protective cap (1) to trans-
port the measuring tool safely.
In the main menu, you can choose whether and after how
long the measuring tool automatically switches off (see
"Main Menu", page 21).
If the battery pack or the measuring tool is not within the op-
erating temperature range specified in the technical data,
the measuring tool will switch off automatically after a brief
warning (see "Errors – Causes and Corrective Measures",
page 23). Allow the measuring tool to reach the correct
temperature and then switch it back on.

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 21).
Temperature measurements will only be correct if the
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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 21).
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-
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1 609 92A 6KU | (06.10.2021)