Operating Instructions
NAV350
Product description
8013889/ZML0/2017-06-09
© SICK AG · Germany · All rights reserved · Subject to change without notice
37
Chapter
3
3.10.3
Distance between NAV350 and the object/surface to be measured
The measurement area on the NAV350 starts at 0.5 m (1.64 ft) in front of the optics (light
output window).
To prevent false measurements, in the case of the recessed installation of the NAV350 the
increase in the size of the laser beam with increasing distance is to be taken into account.
If mounted poorly, objects in the scan range may be continuously detected as the laser
beam is always incident on them.
Fig. 21:
Increase in the size of the beam and safety supplement
The optical axis is used as the reference plane for the distance to be maintained from the
wall; on the vertically mounted NAV350 this axis is approx. 198 mm (7.8 in) above the bot--
tom edge of the housing.
The distance-dependent increase in the size of the beam can be calculated using the
formula:
beam diameter = (distance (mm (in)) × 5.0 mrad) + 20 mm (0.79 in)
1)
The following table shows a few values as examples:
For the assessment of whether the laser beam can be incident on an object, the distance
of half the beam diameter from the optical axis is used.
Important
Use a safety supplement of 5 mm (0.2 in) per metre top and bottom (see
fig. 21 on
page 37
).
Recommendation
For the simplified calculation of the sum of the increase in the size of the beam and safety
supplement, a value of 16 mm (0.63 in) per metre can be used.
1)
Due to the transmit lens.
Distance in m
5 10
15
20
25
30
40
50
60
70
Beam diameter [mm]
45
70
95
120
145
170
220
270
320
370
Tab. 8:
Beam diameter at different distances from the NAV350
Safety supplement
5 mm/m (0.061 in/ft)
Safety supplement
5 mm/m (0.061 in/ft)
198 mm
(7.8 in)
Optical axis
Expanding
laser beam
Distance
