®
N o n - c o n t a c t T e m p e r a t u r e S e n s o r
PS-2197
2
Sample Rate
By default, the sensor collects data at the rate of 10
samples per second. This rate can be changed in the
software.
Attaching the Sensor Handle
The included sensor handle allows the sensor to be held
in a clamp or other device. Attach the handle to the
sensor as illustrated in Figure 1.1.
Figure 1.1: Attaching the sensor handle
Collecting Data
Click Record or press Start in the software. The comput
-
ing device begins to collect data.
About the Sensor
Field of View
The sensor’s field of view is ±35°, as illustrated in Figure
2. The object or surface being measured should fill the
field of view.
Figure 1.2: Field of view
How the Sensor Calculates Temperature
All objects emit infrared radiation. The radiated power per
unit area of an object is given by the Stefan-Boltzmann
law:
I
=
T
4
Where
T
is the objects’ absolute surface temperature,
and
is the Stefan-Boltzmann constant. The emissivity,
, is a property of the object’s surface and can range from
0 to 1. An object with
= 1 is described as a blackbody.
Consider a blackbody of temperature
T
o
whose surface
can be approximated as an infinite plane, and a flat
detector surface of area
A
. The surfaces are parallel to
each other. Because radiation from an infinite plane
propagates as a plane wave, the power flow from the
object to the detector (
P
od
) equals the radiation emitted
by a part of the object surface whose area equals the
detector’s area, regardless of the distance between the
object and detector.
P
od
=
A
T
o
4
The detector itself also radiates in accordance to the
Stefan-Boltzmann law. If the detector’s temperature is
T
a
,
then power radiating from the detector is
P
a
=
A
T
a
4
Therefore, the
net
power absorbed by the detector due to
radiation is
P
=
A
(
T
o
4
T
a
4
)
A thermopile in the sensor produces a voltage,
V
, which
is proportional to
P
. The above equations combine to
give
V
=
k
(
T
o
4
T
a
4
)
Where
k
is a constant.
35° 35°
0.00
0.25
0.50
0.75
1.00
-80°
-60°
-40°
-20°
0°
20°
40°
60°
80°
Angle, Deg
