ISR 12-LO
•
IGAR 12-LO Operating Manual
Controls and Connections
•
21
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)
The aperture is the effective lens diameter of the optics. It is depending on the objective
length which is changing if the measuring distance will be adjusted. The biggest aperture value
belongs to the fully extended objective, the smallest aperture value if the objective is turned to
its smallest size. Intermediate values have to be interpolated (e.g. calculating the spot size if the
measuring distance varies from the adjusted value).
The spot sizes, mentioned in the table above, will be only achieved at the measuring distances
of the corresponding optics or with the focusable optics at the adjusted distance. Decreasing or
increasing the measuring distance enlarges the spot size.
Spot sizes for intermediate distances, that are not shown on the optical profiles, may be
calculated using the following formula:
Aperture-Ø D
Ø M
Ø M
1
Ø M
2
a
a
2
a
1
3.5
D
)
D
M
(
a
a
M
1
1
−
+
=
D
D)
(M
a
a
M
2
2
+
−
=
Note:
The
InfraWin
program includes a calculator (“IR calculator“) that roughly estimates
the unknown values.
Note:
The pyrometer can measure objects at any distance, but it has to be at least as big as
the spot size of the pyrometer.
3.5.2
Adjusting the required measuring distance with optical head
Ι
or
ΙΙ
, fixed adjusted
A tape can be used to determine the distance between the object and
pyrometer. The measuring distance is always measured from the front of the
lens.
If the laser is switched on, its smallest spot is in the measuring distance of
the corresponding optics or adjusted distance and it marks the center as well as the size of the
spot.
3.5.3
Adjusting the required measuring distance with optical head
ΙΙ
,
focusable
For adjustment of the correct distance, untighten
the fixing nut and vary the length of the optical
head by turning the lens tube. In the correctly
focused distance the laser has its smallest spot size
(sharpest image). After adjustment tighten the
fixing nut.
