General Tools and Instruments IRT675 - Manual (Page 5)

OPERATION REMARKS:
• Memory: Activate the record function by pushing the “M”
button. To delete all the records, press the up or down
button to DATA0 and then press the “M” button.
• LOCK: Push the
button to continuously measure and
display the temperature without pulling the measuring
trigger.
• The above functions can always be activated by following
any of the steps of the Operations Mode in the flow chart.
• In SCAN mode, the LCD display both the current
temperature in Celsius or Fahrenheit. The unit will HOLD
the last reading for 30 seconds after the trigger is
released. When the battery is low, the battery icon will
display, but the unit will continue to function.
• While DATA# flashes on the left bottom, the value on the
Main Temperature Display can be recorded in “#” log.
Simply press the “M” button.
°F/°C AND BATTERY CHANGE:
The unit is powered by
“9V” battery and displays
temperature in either °F/°C.
The user has to replace the
battery when the battery
voltage drops below the
voltage for reliable
operation and at the same
time the low battery
symbol will appear. To
change the “9V” battery,
pull and open the unit’s
handle by using the finger.
Change the “9V” battery
with a new one and push
the battery cover back in
place.
TECHNIQUES OF INFRARED THERMOMETER:
FIELD OF VIEW (FOV) RATIO =
DISTANCE TO DIAMETER (DS) RATIO
The field of view is the angle of vision at which the
instrument operates and it is determined by the optics of the
unit. The FOV is the ratio of the distance from the target to
the target diameter. The smaller the target, the closer you
should be to it. When the target diameter is small, it is
important to bring the thermometer closer to the target to
insure that only the target is measured, excluding the
surroundings.
EMISSIVITY:
Emissivity is the ability of an object to omit or absorb energy.
Perfect emitters have an emissivity of 1, emitting 100% of
incident energy.
An object with an emissivity of 0.8 will absorb 80% and
reflect 20% of the incident energy. Emissivity is defined as
the ratio of the energy radiated by an object at a given
temperature to the energy emitted by a perfect radiator at
the same temperature. All values of emissivity fall between
0.0 and 1.0.
Non-contact temperature sensors measure IR energy emitted
by the target, have fast response, and are commonly used to
measure moving and intermittent targets, targets in a
vacuum, and targets that inaccessible due to hostile
environments, geometry limitations, or safety hazard.
The cost is relatively higher, although in some cases it is
comparable to contact devises.
°F/°C switchable
Laser On/Off
“9V” battery
Battery
cover
release
button
IRT675 Manual-FINAL2-050608:Layout 1 5/6/08 9:42 AM Page 5