HT instruments THT70 - Manual (Page 46)

THT70
EN - 44
5.3 USING THE INSTRUMENT
For a typical use of the instrument, please refer to the following procedure:
1. Switch on the instrument by pressing and holding the “ ” key for 3 seconds. After
approx. 20 seconds of internal autotest, the instrument shows its normal measuring
screen. The instrument shows an initial screen like the one shown in Fig. 70.
Fig. 70: Initial screen
2. It takes approx. 30 seconds for the instrument to become fully operating. During this
time interval, the instrument carries out an automatic calibration and the internal
commutations may produce some noise
CAUTION
The autocalibration sequence starts when the instrument is switched on and
continues during the thermal cameras normal operation, during which the
image freezes for a few seconds in order to eliminate offset errors. The
noise produced by the commutation of internal parts is not to be considered
as a problem of the instrument.
3. Before any measuring operation, correctly focus the thermal camera in order to prevent
having grossly inaccurate measurements and a low quality of the saved image (see §
5.1.1).
4. For accurate temperature measurements, make sure the surface of the measured
object is always bigger than the surface measurable by the instrument, which is given
by the instruments field of view (FOV). The instrument has a field of view of 25° x 19°
and a detection vector of 384x288 (110592) pixels (see Fig. 71).
Fig. 71: Representation of the instruments field of view (FOV)
384 pxl
288
p
xl
19°
25°
25°