Banner M18 Series - Manual (Page 3)

M18 Fixed-Field Mode
Models
Cutoff
Point
Cable
Output
Type
Excess Gain
with 25 mm far limit cutoff
1
10
100
1 mm
.04 in 10 mm
.4 in
100 mm
4 in
.1 mm
.004 in
E
X
C
E
S
S
G
A
I
N
DISTANCE
1000
M18 Series
Fixed-field mode
with 25 mm far
limit cutoff
M18SN6FF25
25 mm (1")
2 m (6.5')
NPN
M18SN6FF25Q 4-Pin Euro-style QD
M18SP6FF25 2 m (6.5')
PNP
M18SP6FF25Q 4-Pin Euro-style QD
with 50 mm far limit cutoff
1
10
100
1 mm
.04 in 10 mm
.4 in
100 mm
4 in
.1 mm
.004 in
E
X
C
E
S
S
G
A
I
N
DISTANCE
1000
M18 Series
Fixed-field mode
with 50 mm far
limit cutoff
M18SN6FF50
50 mm (2")
2 m (6.5')
NPN
M18SN6FF50Q 4-Pin Euro-style QD
M18SP6FF50 2 m (6.5')
PNP
M18SP6FF50Q 4-Pin Euro-style QD
with 100 mm far limit cutoff
1
10
100
1 mm
.04 in 10 mm
.4 in
100 mm
4 in
.1 mm
.004 in
E
X
C
E
S
S
G
A
I
N
DISTANCE
1000
M18 Series
Fixed-field mode
with 100 mm far
limit cutoff
M18SN6FF100
100 mm
(4")
2 m (6.5')
NPN
M18SN6FF100Q 4-Pin Euro-style QD
M18SP6FF100 2 m (6.5')
PNP
M18SP6FF100Q 4-Pin Euro-style QD
The excess gain curves above show excess gain vs. sensing distance for M18 Series fixed-field sensors with 25-, 50- and 100-millimeter
cutoffs. Maximum excess gain for the 25-mm models occurs at a lens-to-object distance of about 7 mm; for the 50-mm models, at about
10 mm; and for the 100-mm models, at about 20 mm. Sensing at or near these distances will make maximum use of each sensor’s
available sensing power. Backgrounds and background objects must always be placed beyond the cutoff distance.
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 important to sense it at or near the distance of maximum
excess gain.
The effects of object reflectivity on cutoff distance, though small, may be important for some applications. Sensing of objects of less than
90% reflectivity causes the cutoff distances to be “pulled” slightly closer to the sensor. 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 heavy horizontal graph line at excess gain = 10. An object of this
reflectivity results in far limit cutoffs of approximately 20, 40 and 70 mm (for 25-, 50- and 100-mm cutoff models, respectively).
Objects with reflectivity greater than 90% return more light to the sensor. For this reason, highly reflective backgrounds or background
objects such as mirrors, polished metal, and other sources of specular reflections require special consideration. To use a highly reflective
background, place it as far beyond the cutoff distance as possible and angle it to direct reflected light away from the sensor.
EZ-BEAM M18 Series Fixed-Field Sensor Setup Tips
For highest sensitivity, the sensor-to-object distance should be such that the object will be sensed at or near the point of maximum ex-
cess gain. The background must be placed beyond the cutoff distance. Following these two guidelines makes it possible to detect objects
of low reflectivity, even against close-in reflective backgrounds.
EZ-BEAM M18 Series Sensors
P/N 049201 Rev. C www.bannerengineering.com - tel: 763-544-3164 3