LumaSense Technologies ISR 320 - Manual (Page 16)

ISR 320 Manual Controls and Installation 16
3.3 Optics
3.3.1 Spot Sizes
The ISR 320 has fixed optics for 300 mm or 800 mm measuring distance.
The table of spot sizes in relation to measuring distance shows examples of the pyrometer’s spot
size M [mm] in relation to the measuring distance a [mm] (min. 90% of the radiation intensity).
Increasing or decreasing the measuring distance will change the spot size.
.
Note: In the 1-color (mono) mode, the pyrometer can measure objects at any distance
(whether focused or non-focused). However, the object has to be bigger than or at
least as big as the spot size of the pyrometer in the measuring distance.
In the 2-color (ratio) mode, the object can be somewhat smaller than the spot
diameter.
ISR 320 (700 to 1700°) a = 300 ISR 320 (700 to 1700°) a = 800
Measuring Distance
a [mm]
Spot Diameter
m [mm]
Measuring Distance
a [mm]
Spot Diameter
m [mm]
300 3 800 8
800 12.3 1300 19.9
1000 35.7 2000 36.5
Note: Effective aperture D for all temperature ranges is 11 mm.
3.3.2 Deviation from the focused measuring distance
Spot sizes for non-focused distances (shorter or longer than the focused distance) may be
calculated by using the formula below.
Formula for Calculating Spot Sizes
The InfraWin software also includes a Spot Size Calculator that calculates the data for the
non-focused regions, if you enter the values of aperture D, focused measurement distance a,
and focused measuring field diameter M as found in the above table (see section 3.3.1).