9
2
GENERAL FEATURES
2.1
General
Temperature measurements of a liquid or gaseous compound have been successfully made with thermoelectric or
expansion thermometers thanks to the good thermal exchange of the sensor with the fluid.
With solid bodies a good thermal exchange is difficult to be obtained and an additional measuring error should be
considered.
A direct contact measurement is impractical when the object being measured is moving, it cannot be touched with a
thermoelectric sensor because of electrical hazard or of other reasons.
A non-contact IR temperature measurement is the best solution to the above application problems.
Also other applications benefit because non-contact thermometers do not add or remove heat or disturb the process in
any way, and there is no wear and tare on the instrument.
2.2
Optical System
The optical system is equipped with a main objective to focus the infrared energy into the infrared detector through a
single lens, a filter and a field stop which defines the visual cone and therefore the target dimensions.
As the detector is placed in the focal point of the measurement portion of the optical system no focusing operations are
required.
A secondary, but extremely important objective, is the correct pinpointing of the target as described below.
The optical diagrams are shown in the previous specification section.
2.3
Target pinpointing
A correct aiming at the target is an important factor of a non-contact thermometer. The immediate evaluation of the
smallest measurable target area is also a positive key factor in many applications.
The following types of pinpointing are available :
•
A “V” groove on the up side of the instrument can be used stretching the arm.
•
Twin laser pointers to define, at distance, the measurable target dimensions. Two versions are available with crossing
or parallel twin lasers. The twin crossed lasers are suggested for target distance upper than 5 meters.
•
Combination of twin lasers and direct telescope viewing for universal applications mainly required for a high distance
targets (more than 10 meters) and high temperature targets (more than 1000 °C) where laser spots are not visible .
•
Combination of twin lasers and a red point pinpointing for universal applications mainly required for high temperature
target where laser spots are not visible
With a laser pinpointing the operation of the instrument is extremely simplified. You simply aim at the target and read the
temperature.
The installation procedures for telescope and red point pinpointing, please refers to the dedicated chapters.
2.4
Taking measurements
OSP
portable thermometers are accurate, rugged and compact.
Its modern and practical design allows an easy handling and aiming, either at arm length or using a tripod mount, to
obtain current temperature value, average, minimum, maximum and difference temperature measurement values.
Its analogue to digital outputs allows a continuous documentation on a continuous trace recorder or on a serial printer.
Using the keyboard it is also possible to enable the instrument to measure one of the computed values in addition to the
actual temperature value measurement:
MAX
maximum temperature recorded during current measurement
MIN
minimum temperature recorded during current measurement
DIF
difference between MAX and MlN
AVG
average temperature for entire measurement
Tamb
ambient temperature
