Hilti PT-C Manual De Instrucciones Original página 39

6 Operation
Flip the protective cap open for measuring. Make sure that the infrared sensor is not capped or obstructed
while you are working.
6.1 Switching on / off
1. To switch the measuring tool on, press the on/off button.
▶ A start sequence appears on the display.
▶ After the start sequence, the measuring tool immediately starts measuring and continues to measure
until it is switched off.
During the first minutes the measuring tool might recalibrate frequently because sensor temperature
and ambient temperature have not yet equalized. The repeated sensor calibration enables accurate
measurement.
During this time the temperature readout might show ~. The thermal image freezes briefly while
sensor calibration is in progress. Severe fluctuations in ambient temperature intensify this effect.
Consequently, switch the measuring tool on a few minutes before the start of measurement so
that it can stabilize itself thermally.
2. To switch the measuring tool off, press the on/off button.
▶ The measuring tool saves all settings and then switches off.
3. Close the protective cap for safe transport of the measuring tool.
In the main menu you can navigate to 'Tool' → 'Shutdown Time' and select whether and after
what period of time the measuring tool will switch off automatically. → page 38
6.2 Assignment of temperatures on the basis of the scale
The scale is shown on the right-hand side of the display.
The values at the top and bottom ends orient themselves
by the maximum temperature and the minimum temper-
ature registered in the thermal image. 99.9 % of the en-
tire set of pixels are analyzed for the scale. Assignment
of a color to a temperature value in the image is linear.
The different color tones, therefore, correlate to temper-
atures within these two boundary values. A temperature
that is exactly midway between maximum and minimum,
for example, is in the middle of the scale's color range.
To determine the temperature of a given area, position the measuring tool in such a way that the crosshairs
with temperature reading are aimed at the desired spot or area. In the automatic setting, the color spectrum
of the scale is always distributed linearly over the entire measured area within the maximum and minimum
temperatures.
The measuring tool shows all measured temperatures in the measured area in relation to each other. If the
heat in an area in a colored visualization for example is shown blue in the color palette, this means that the
blueish areas belong to the colder measured values in the current measured area. However, these areas
might well be in a temperature range that can lead to injuries under certain circumstances. Consequently,
always check the temperature readings shown on the scale or directly where the crosshairs are located.
6.3 Setting emissivity for surface temperature measurements
An object's emissivity ε depends on the material and the structure of the surface. It is a measure of the
infrared heat emission of the object compared to an ideal heat emitter (black body, emissivity ε = 1) and is
therefore a value between 0 and 1.
Surface temperature is determined by non-contact measurement of the natural infrared heat emitted by the
targeted object. For correct measurements the emissivity set in the measuring tool has to be checked before
each measurement and, if necessary, adapted to the object to be measured.
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