HT instruments HT3310 - Manual (Page 11)

HT3301-HT3310
EN - 10
6. OPERATING INSTRUCTIONS
6.1. TEMPERATURE MEASUREMENT
6.1.1. Infrared measurement mode
1. Select the desired additional parameter displayed according to paragraph 4.4.1
2. Hold the meter by its handle grip and point it toward the surface to be measured
3. Pull and hold the trigger to turn the meter on and begin testing. The display will light if
the battery is good. Replace the battery if the display does not light. While measuring,
the SCAN display icon will appear in the upper left corner of the LCD
4. Release the trigger and the HOLD icon will appear on the LCD indicating that the
reading is being held
5. The meter will automatically power off after approximately 7 seconds after the trigger is
released
6. The Fig. 5 shows the ratio between distance of the meter from the object under test
and the surface diameter of application. As the distance (D) from the object increases,
the spot size (S) of the area measured by the unit becomes larger. The relationship
between distance and spot size for each unit is listed below. The focal point for each
unit is 914mm (36”). The spot sizes indicate 90% encircled energy
HT3301 – Spot size HT3310 – Spot size
Fig. 5: Diameter of application surface S with reference distance D from object
7. Make sure that the target is larger than the unit’s spot size (see Fig. 6) The smaller the
target, the closer you should be to it. When accuracy is critical, make sure the target
is at least twice as large as the spot size. To find a hot spot aim the thermometer
outside the area of interest, then scan across with an up and down motion until you
locate hot spot
Fig. 6: Spot size area