FLIR
TG54_TG56
User
Manual
25
Document
Identifier:
TG54_TG56
‐
en
‐
US_AA
9.2
Infrared
Energy
and
IR
Thermometer
Theory
Infrared
energy
is
part
of
a
complete
range
of
radiation
called
the
electromagnetic
spectrum.
The
electromagnetic
spectrum
includes
gamma
rays,
X
‐
rays,
ultraviolet,
visible,
infrared,
microwaves
(RADAR),
and
radio
waves.
The
only
difference
is
their
wavelength
or
frequency.
All
of
these
forms
of
radiation
travel
at
the
speed
of
light.
Infrared
radiation
lies
between
the
visible
and
RADAR
portions
of
the
electromagnetic
spectrum.
The
primary
source
of
infrared
radiation
is
heat
or
thermal
radiation.
Any
object
which
has
a
temperature
radiates
in
the
infrared
portion
of
the
electromagnetic
spectrum.
Even
objects
that
are
very
cold,
such
as
an
ice
cube,
emit
infrared.
When
an
object
is
not
quite
hot
enough
to
radiate
visible
light,
it
will
emit
most
of
its
energy
in
the
infrared.
For
example,
hot
charcoal
may
not
give
off
light,
but
it
does
emit
infrared
radiation,
which
we
feel
as
heat.
The
warmer
the
object,
the
more
infrared
radiation
it
emits.
IR
Thermometers
measure
an
object’s
surface
temperature.
The
thermometer’s
optics
sense
an
object’s
emitted,
reflected,
and
transmitted
energy.
The
TG
Series
translates
the
sensed
information
(targeted
by
the
Laser)
into
a
temperature
reading
that
is
displayed
in
text
on
the
center
of
the
display.
If
the
thermometer
measurement
exceeds
the
published
temperature
range,
the
display
will
indicate
OL.
The
amount
of
IR
energy
emitted
by
an
object
is
proportional
to
an
object's
temperature
and
its
ability
to
emit
energy.
This
ability
is
known
as
emissivity
and
is
based
on
the
material
of
the
object
and
its
surface
finish.
Emissivity
values
range
from
0.1
for
a
very
reflective
object
to
1.00
for
a
flat
black
finish.
The
TG
Series
has
both
adjustable
and
preset
emissivity
settings.
There
are
four
(4)
presets
and
an
adjustable
emissivity
span
from
0.10
to
0.99.
See
the
Appendix
for
a
list
of
common
materials
and
their
respective
Emissivity
factors.
Access
the
Programming
menu
(covered
in
Section
6)
to
set
the
desired
emissivity
factor.
