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: +1-763-544-3164

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