Banner Q60 Background Suppression Series - Manual (Page 3)

P/N 114348
3
Q60LAF Series Laser Adjustable-Field Sensors
Banner Engineering Corp. • Minneapolis MN, U.S.A.
www.bannerengineering.com • Tel: 763.544.3164
Color Sensitivity
The effects of object reflectivity on cutoff distance, though small, may be im por tant for
some ap pli ca tions.
The excess gain curves on page 1 were generated using a white test card of 90%
reflectance. Objects with reflectivity of less than 90% reflect less light back to the
sensor, and thus require pro por tion ate ly more excess gain in order to be sensed
with the same reliability as more reflective objects. When sens ing an object of very
low reflectivity, it may be especially im por tant to sense it at or near the distance of
maximum excess gain.
It is expected that at any given cutoff setting, the actual cutoff distance for lower
reflectance targets will be slightly shorter than for higher reflectance targets (see
Figure 4). This behavior is known as color sensitivity.
The percentage of deviation indicates a change in the cutoff point for either 18% gray
or 6% black targets, relative to the cutoff point set for a 90% reflective white test card.
For example, the cutoff point decreases 10% for a 6% reflectance black target when
the cutoff point is adjusted for 1700 mm (67") using a 90% reflectance white test
card. In other words, the cutoff point for the black target is 1530 mm (60") for this
setting.
NOTE: Sensing at closer than the minimum specified range is not guaranteed.
Figure 4. Q60LAF performance
0
-1
-2
-3
-4
-5
-6
-7
-8
-9
-10
-12
200 400 600 800 1000 1200 1400 1600 1800 2000
Cutoff Setting (90% White Card)
Percent Deviation
Cutoff Point Deviation
250
300
200
150
100
50
0
200 400 600 800 1000 1200 1400 1600 1800 2000
Cutoff Distance (mm) with 90% White Card
Minimum Range (mm)
Class 2 Laser 18% Gray Card
6% Black Card
Class 1 Laser 18% Gray Card
6% Black Card
Minimum Range vs. Cutoff Setting*
*NOTE: Minimum range is independent of target reflectivity
Class 1
Class 2
6.0
4.0
2.0
0
200 400 600 800 1000 1200 1400 1600 1800 2000
Cutoff Setting (mm) with 90% White Card
Hysteresis (% of Cutoff)
Hysteresis
250
300
200
150
100
50
0
200 400 600 800 1000 1200 1400 1600 1800 2000
Cutoff Distance (mm) with 90% White Card
Minimum Range (mm)
Class 2 Laser 18% Gray Card
6% Black Card
Class 1 Laser 18% Gray Card
6% Black Card
Minimum Range vs. Cutoff Setting*
*NOTE: Minimum range is independent of target reflectivity
Class 1
Class 2