Banner WORLD-BEAM QS18 Laser Series - Manual (Page 2)

Sensor-to-Target
Distance (X)
Beam Displacement (Y)
for 1º of Misalignment
Sensing Distance = X
Ø = Misalignment Angle
Y = X(tan Ø)
Y
Figure 1. Beam displacement per degree of misalignment
1.5 m (5') 25 mm (1")
3 m (10') 50 mm (2")
6 m (20') 100 mm (4")
10 m (33') 150 mm (6")
Alignment Tip
When using a small retroreflective target at medium or long range, it is often useful to temporarily attach (or suspend) a
strip of retroreflective tape (e.g., BRT-THG-2) along a line that intersects the actual target. The visible red laser beam is
easily seen in normal room lighting on such tape. Sight along the beam toward the target (from behind the sensor). Move
the sensor to sweep the laser beam back and forth across the retro tape strip. Use the tape strip to guide the beam onto
the target.
Consider using sensor mounting bracket model SMB18SF or SMB3018SC. A swivel bracket can simplify multiple-axis
alignment. Alignment is complete when the visible image is centered on the retro target. The perpendicularity of the laser
beam to the face of the retro target is forgiving, just as it is with a conventional retroreflective sensor.
Effective Beam Size
Unlike conventional retroreflective sensors, the retroreflective laser has the ability to sense relatively small profiles. The
table indicates the diameter of the smallest opaque rod which will reliably break the laser beam at several sensor-to-object
distances. These minimum object sizes were measured with the sensor aligned to a BRT-51X51BM reflector and with the
sensor set for an excess gain of about 10X. Flooding effects are possible when the gain is much higher. This means that
sensor gain may have to be reduced in some situations in order to reliably detect these minimum object sizes.
Table 1: Minimum object detection size vs distance from sensor
Distance from Sensor to Object Minimum Object Detection Size
0.3 m (1 ft) 2.5 mm (0.10 in)
1.5 m (5 ft) 5.0 mm (0.20 in)
3 m (10 ft) 6.5 mm (0.26 in)
6 m (20 ft) 10 mm (0.40 in)
10 m (33 ft) 13 mm (0.52 in)
CAUTION: Never stare directly into the sensor lens. Laser light can damage your eyes. Avoid
placing any mirror-like object in the beam. Never use a mirror as a retroreflective target.
Note that the shape of the beam is elliptical. The minimum object sizes listed assume passage of the rod across the major
diameter of the ellipse (worst case). It may be possible to detect objects smaller than the sizes listed if the direction in
which the objects pass through the beam can be controlled.
Retroreflector Recommendations
• BRT-51X51BM recommended for beam-block applications up to 10 m range.
• BRT-TVHG-2X2 recommended for applications up to 1.5 m range. (This retroreflector is an adhesive-backed
sealed tape with micro-prism geometry.)
Both reflectors are included with the sensor. See Accessories for information about ordering replacements or other
reflector options.
NOTE: When sensing objects with specular reflections, use the sensor’s side-mounting option to
optimize sensing performance.
WORLD-BEAM ® QS18LLP Series
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