User guide

Special-purpose glass and plastic fiber optic sensors for low-contrast applications
Highly sensitive to very small signal changes; fast response
Automatic gain control circuit continually adjusts emitter
output to maintain system gain
Ideal for low contrast applications such as web flaw,
thread break, and falling parts detection
Sensors operate from 10-30V dc.
One NPN (sinking) and one PNP (sourcing) output;
150 mA max. (continuous) load
LED indicators for
POWER ON, OUTPUT CONDUCTING, and
AGC LOCK conditions
Selectable light- or dark-operate; no false pulse on power-up
D12DAB6FVs for glass fibers; D12DAB6FPs for plastic fibers
Printed in USA P/N 38384A8A
At right, a
D12DAB6FP
plastic fiber
optic sensor,
mounted on a
DIN rail, with
a bifurcated
plastic fiber
optic assembly
attached.
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D12DAB6 Series DIN Rail AC-coupled Fiber Optic Sensors
Sensor Features
(top panel shown)
A switch on the sensor's top panel selects either light- or
dark-operate. When light-operate is selected, output
occurs on a dark-to-light transition. When dark-operate
is selected, output occurs on a light-to-dark transition.
D12s are constructed of rugged black ABS (Cycolac
®
KJB). They are designed for mounting directly to a 35
mm DIN rail, or may be mounted via a convenient
through-hole bracket (included, see page 2). The trans-
parent housing cover is acrylic. All D12 sensors are rated
NEMA 4 (IEC IP 66).
Sensors are available with either 6-1/2 foot (2 m) or 30
foot (9 m) attached PVC-jacketed cable, or a 6 inch
pigtail with attached 4-pin pico-type QD connector.
A model listing appears on page 4.
D12DAB6 Series sensors are compact, ac-coupled sensors designed for use
with Banner glass or plastic fiber optics. They are intended for applications
in which the light signal change is so small that sensitivity adjustment of
ordinary dc-coupled sensors is difficult or impossible. D12DAB6 Series
sensors can respond to even smaller signal changes than the standard D12
fiber optic sensors, and are less affected by gradual signal changes due to
dirt buildup, etc. Typical applications include thread break detection, web
flaw detection, and detection of small parts falling randomly from vibratory
feeders or small presses.
Many low contrast photoelectric sensing applications present problems to
dc-coupled sensors because of switching hysteresis. Switching hysteresis
is a designed-in property of dc-coupled sensors that causes the "turn-on
point" of the sensor's dc-coupled amplifier to be slightly different than the
"turn-off point". This is to prevent indecision and erratic operation of the
sensor's output circuit when the light signal is at or near the switching point
of the dc-coupled amplifier.
With their ac-coupled amplifier, D12DAB6 Series sensors reliably amplify
the small signal changes found in many low contrast sensing applications.
An automatic gain control (AGC) feedback system locks onto the light
signal and continually adjusts the light intensity of the emitter so that the
system is always maintained at the desired reference level regardless of the
sensing range or the degree of environmental contamination. A multi-turn
control enables setting of the amplifier sensitivity.
D12DAB6 Series sensors operate from +10 to 30V dc, and have two
normally open outputs: one NPN (sinking) and one PNP (sourcing).
Maximum switching capacity for each output is 150 mA (continuous). A
hookup diagram is given on page 4.
Model D12DAB6FV models are for use with Banner glass fiber optic
assemblies. The D12DAB6FP plastic fiber models may be used with
either the small diameter (.020") or large diameter (.040") Banner cut-
to-length plastic fiber optics.
D12DAB6 Series sensors have a POWER ON indicator, a LOCK indicator
that lights when the AGC circuit has locked onto the signal, and a LOAD
indicator that lights whenever the sensor's outputs are energized.
Description