Cut Sheet

S30FF Sensor
R1 = Near Detector
R2 = Far Detector
E = Emitter
Cutoff
Distance
Highly
Reflective
Background
E
R2
R1
Strong
Direct
Reflection
to R1
Core of
Emitted
Beam
Fixed Sensing
Field
Figure 3. Reflective Background - Problem
S30FF
R1
R2
E
R1 = Near Detector
R2 = Far Detector
E = Emitter
Core of
Emitted
Beam
Cutoff
Distance
Reflective
Background
Fixed Sensing
Field
Strong
Direct
Reflection
Away
From Sensor
Figure 4. Reflective Background - Solution
R1 = Near Detector
R2 = Far Detector
E = Emitter
S30FF
R1
R2
E
Fixed
Sensing
Field
Cutoff
Distance
Reflective
Background
or
Moving Object
A reflective background object in this position or moving across the
sensor face in this axis and direction may cause false sensor response.
Figure 5. Object Beyond Cutoff - Problem
Fixed
Sensing
Field
E = Emitter
R1 = Near Detector
R2 = Far Detector
S30FF
Cutoff
Distance
E, R1, R2
A reflective background object in this position or moving across the
sensor face in this axis will be ignored.
Figure 6. Object Beyond Cutoff - Solution
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 is slightly shorter than for higher
reflectance targets. This behavior is known as color sensitivity.
For example, an excess gain of 1 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 in) for the 200 mm (8 in) cutoff model, for example; 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.
S30 Sensors AC-Voltage Series
P/N 121519 Rev. A www.bannerengineering.com - Tel: [phone]