3.2 Measuring Metallic Targets
In general, infrared thermometers can easily measure non-
metallic surfaces because they emit most of their potential
heat. Metallic surfaces, on the other hand, are poor emit-
ters and require special treatment before infrared ther-
mometers can accurately measure their temperature.
Fortunately, that special treatment is simple and can be
easily accomplished by marking the metallic surface you
wish to measure with a non-metallic substance such as a
solid paint marker. Other substances such as grease, oil,
or tape may also be used. It is only necessary to mark an
area slightly larger that the OS950 nosepiece, when operat-
ing in AECS mode. When operating in MAX or SCAN
modes, mark the appropriate target area for the measuring
distance from the target, based on a 1 to 1 Field of View.
3.3 Optimizing AESC Measurements for
NIST Traceablity
If you look at the OS950's nosepiece, you will see that it is
really a small reflective cup with the sensor's window at its
base. When the OS950's nosepiece touches the surface of
an object, that reflective cup automatically controls what the
sensor sees by eliminating variables such as target emis-
sivity and extraneous radiation. Patented by Exergen as
the Automatic Emissivity Compensation System (AECS),
this unique design ensures accurate readings every time.
To optimize results, make sure that the nosepiece is flush
with the target when possible, so that the reflective cone
can complete trap out any light or incident radiation from
the environment.
3.4 Measuring Transparent Materials
Although transparent materials pass visible light, many visi-
bly transparent materials are opaque in the infrared and
can be directly measured by the OS950.
To test for infrared transparency, touch the OS950 to the
target's surface and pass a heat source such as your hand
or a penlight through the sensor's field of view on the other
side of the material. If the OS950 responds to the heat
source, the material is transparent in the infrared, and
requires marking the surface for proper measurement.
Mark the surface with an opaque non-metallic coating, such
as paint or grease.
Alternatively, place a shiny metallic object, such as alu-
minum foil, behind the transparent material. The shiny
metal will reflect the target's heat back to the OS950.
3.5 Measuring Wet or Icy Surfaces
Wet or icy surfaces may interfere with the OS950's read-
ings. Water and other liquids are good targets, but evapo-
ration lowers their surface temperatures.
Frost forms on a surface at the freezing point of water.
Frozen foods or similar targets will form frost unless the
environment is controlled. If frost forms, the OS950 will
measure the temperature of the frost instead of the object's
temperature.
Melting ice will read slightly higher than 32 °F (0°C)
because the instrument actually measures the air condens-
ing on the ice, a reaction that generates a small amount of
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