Banner MINI-BEAM Series - Manual (Page 2)

Installation and Alignment
Proper operation of the sensors requires they be mounted securely and aligned properly. Excessive movement or vibration
can cause intermittent or false operation due to loss of alignment. For maximum mechanical stability, final-mount these
sensors in 18-mm holes by their threaded barrels or use a mounting bracket .
C
A
B
Figure 1. Receiver Adjustments
A - “AID” Indicator LED lights when the sensor sees the reflection of its own
modulated light and pulses at a rate proportional to the strength of the received
light signal
B - 15 turn gain adjustment and light/dark operate switch
C - Gasketed acrylic cover
Regarding the light/dark operate switch:
• Turn switch fully clockwise for light operate (sensor outputs conduct
when sensing light is received)
• Turn switch fully counterclockwise for dark operate (sensor outputs
conduct when sensing light is not received)
1) Begin with the emitter mounted securely in place. For
small-parts counting applications, stretch a string between
the emitter and receiver lenses to ensure the sensing beam
passes through the center of the sensing location. For less
critical applications, the receiver may be initially positioned
by line-of-sight placement. Mount the receiver, leaving a
means for movement.
2) Apply power to the emitter and receiver, and advance
the receiver’s 15-turn GAIN control to maximum (clockwise
end of rotation). The GAIN control is clutched at both ends
to avoid damage and will “free-wheel” when either endpoint
is reached.
If the receiver is “seeing” the emitter’s light beam, the
receiver alignment LED is on. Move the receiver up-down-
right-left (include angular rotation) to obtain the fastest
receiver LED pulse rate. If a pulse is not observable (too
fast to count), reduce the GAIN control (counterclockwise
rotation) to obtain a countable pulse rate of one to five
beats per second. Note: to aid alignment at short ranges, it
may help to further reduce the strength of the light signal
by temporarily masking the emitter and/or receiver lens
with tape or a sheet of paper.
Object Emitter
Receiver
Figure 2. Opposed Mode Alignment. Move the receiver to obtain the
fastest LED pulse rate.
3) Repeat the alignment motions after each GAIN reduction. When you have found the receiver orientation that produces
the fastest pulse rate, mount the receiver solidly in that position. Remove any masking material, and increase the receiver
GAIN to maximum. Test the system by placing the object to be detected into the sensing position. The receiver LED
indicator should go off. If it does not go off, the cause is probably either “flooding” or “burn-through”.
Flooding occurs when a portion of the effective beam passes around the object to be sensed and activates the receiver.
Check that the object completely breaks the beam and that the beam is centered on the object. Add apertures, if
necessary, to tailor the effective beam to the size or profile of the object being sensed. Burn-through refers to a portion of
the emitter’s light energy passing through a thin or translucent object and activating the receiver. Try sensing at a reduced
GAIN setting or consider an alternative sensing scheme.
MINI-BEAM SM31E/R Opposed Mode Sensors
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