Q403E Banner Engineering Corp., Q403E Datasheet - Page 3

• Manufacturer Part Number: Q403E
• Manufacturer: Banner Engineering Corp.

Banner Engineering Corp.
www.bannerengineering.com • Tel: [phone]
•
Minneapolis, MN U.S.A.
Color Sensitivity
The effects of object reflectivity on cutoff distance, though small, may be important for
some applications. 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-of-Merit information on page 5). This behavior is known as color sensitivity.
For example, an excess gain of 1 (see page 5) for an object that reflects 1/10 as much light
as the 90% white card is represented by the horizontal graph line at excess gain = 10. An
object of this reflectivity results in a far limit cutoff of approximately 190 mm (7.5") for the
200 mm (8") cutoff model; thus 190 mm represents the cutoff for this sensor and target.
These excess gain curves 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 proportionately more excess gain in order to be sensed with the same reliability as
more reflective objects. When sensing an object of very low reflectivity, it may be especially
important to sense it at or near the distance of maximum excess gain.
Figure 3. Reflective background – problem
Figure 5. Object beyond cutoff – problem
R1 = Near Detector
R2 = Far Detector
Q40 sensor
E = Emitter
A reflective background object in this position or
moving across the sensor face in this axis and
direction may cause false sensor response.
E
R1 = Near Detector
R2 = Far Detector
Q40 sensor
= Emitter
R1
R2
E
E
R2
R1
Core of
Emitted
Beam
Fixed Sensing Field
Q40 Sensors – ac-Voltage Series
Strong
Direct
Reflection
to R1
Sensing
Fixed
Field
Cutoff
Distance
Distance
Cutoff
Moving Object
Background
Reflective
Reflective
Background
or
Figure 4. Reflective background – solution
Figure 6. Object beyond cutoff – solution
A reflective background object in this position or
moving across the sensor face in this axis will be
ignored.
Q40 sensor
R1 = Near Detector
R2 = Far Detector
E
R2 = Far Detector
R1 = Near Detector
E = Emitter
Q40 sensor
= Emitter
E, R2, R1
R1
R2
E
Fixed Sensing Field
Emitted
Core of
Beam
Sensing
Fixed
Field
Cutoff
Distance
Strong Direct
Reflection
Away
From Sensor
P/N 121515
Cutoff
Distance
Reflective
Background
Moving Object
Background
Reflective
or
3