HT instruments THT70 - Manual (Page 47)

THT70
EN - 45
The representation of the ratio D (distance from the object) / S (surface of the object) for
an instrument provided with 22mm lens is described below.
Fig. 72: Representation of the instruments D/S ratio
In the representation, it is possible to see how the IFOV (Instant Field Of View =
geometrical resolution of the instrument = size of the single pxl of the IR sensor) is equal
to 1.14mm at a distance of 1m of the instrument from the object being measured. This
means that the instrument is capable of carrying out correct temperature measurements at
a distance of 1m on objects with a size not lower than 1.14 mm.
5. The typical application of thermal cameras is the one in which it is necessary to detect
a temperature difference between two adjacent objects, as this kind of analysis is often
sufficient to identify anomalies in electrical and mechanical appliances, etc. In such
situations, in which an accurate temperature measurement is not strictly necessary,
emissivity value may be set to “1” (see § 5.2.2.5), it is not necessary to consider the
objects surface, its distance and the field of view). However, if accurate measures are
required (e.g. the temperature of an electric motor), it is necessary to correctly set the
parameters previously described in this manual.
6. Correctly set the temperature range of the image (see § 5.2.1), defining the adequate
values according to the MIN and MAX temperatures detected within the measured
area.
7. Frame the objects to be measured by using the laser pointer, if necessary (see §
4.2.5). The instrument displays the temperature values associated with the measuring
cursors.
8. Use the T key (see § 5.2.4.1) to freeze the image on the display and save it in the
internal memory of the instrument or on the external micro SD card. The instrument
saves the images in sequence with file name “YYMMDD_xxxxT”. Enter possible voice
(see § 5.2.4.2) or text (see § 5.2.4.3) annotations onto the saved image.
9. Touch the icon “ ” to see the saved images again (see § 5.2.5).