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Allen-Bradley 42JS VisiSight Installation And Operating Instructions page 2

Photoelectric sensors

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Sensor Indicators
Green LED
Yellow Output
LED
LED Status
OFF
ON
Green
Flashing (6 Hz)
Flashing (1.5 Hz)
OFF
Yellow
ON
– Black wire or pin 4 of connector.
Background Suppression Sensors
Target
Note: Due to the detection method, targets travelling
horizontal to the sensor's optics are detected. Targets
travelling vertically may not be accurately detected. For
reliable background suppression, a minimum separation
distance of 6 mm is recommended between the target and
the background.
Sensor Alignment
1. Ensure that the sensitivity knob is set at its maximum
(factory default) setting.
2. Pan the sensor left, right, up, and down to center the beam
on the sensed object (for diffuse), reflector (for
retroreflective) or transmitter (for transmitted beam). Affix
the sensor position when the green LED is ON (not
flashing) and the yellow output LED is ON (light sensed
and L.O. output energized). This set up assures a good
margin and that the signal received is greater than twice
the signal required to energize the L.O. output.
3.
a. For diffuse applications, remove the object being sensed
and observe the green LED. If the green LED is flashing
(at 6 Hz), it indicates that the sensor is receiving more
than half the signal required to energize the L.O. output
when there should be minimal or no received signal. It
indicates that the sensor is getting close to detection of
the background. Stability may be optimized by reducing
the reflectivity of the background or reducing the
sensitivity. Reducing the sensitivity shortens the sensing
range. If sensitivity is reduced, check that both the green
and yellow LEDs are on when the object is detected
(step 2 above). In applications where full range is
Sensitivity
Adjustment
Knob
min
max
Power is Off
Power is On
Unstable ( 0.5 < Margin < 2)
Output short-circuit protection active
Output de-energized –
Output energized –
needed, i.e., sensitivity cannot be reduced, the green
LED may be left flashing.
b. For retroreflective and transmitted beam applications,
place the object to be sensed in the beam path and
observe the green LED. If the green LED is flashing (at
6 Hz), it indicates that sensor is receiving more than half
the signal required to energize the L.O. output when
there should be minimal or no received singal. It
indicates that the object being detected is letting some
light go through (semi-transparent or too small in size).
Adjust sensitivity and repeat step 2.
Crosstalk Avoidance
For applications of transmitted beam sensors requiring
adjacent pairs to be mounted in close proximity, use red LED
and infrared LED pairs as adjacent pairs.
The following spacing (center to center) between the adjacent
pairs should be maintained to avoid crosstalk:
1. Red LED pair adjacent to infrared LED pair:
a. 60 mm (2.4 in.) for sensing range up to 1.6 m (4.8 ft)
b. 20 mm (0.8 in.) for sensing range greater than 1.6 m
(4.8 ft)
2. Two adjacent pairs of red LED models or two adjacent
pairs of infrared LED: 360 mm (14 in.)
Two pairs of red LED or two pairs of infrared LED can be
mounted adjoining each other by transposing the emitter and
receiver positions of the second pair vs. the first pair. There is
no crosstalk as each receiver only receives signal from one
emitter.
Mounting the Sensor
Securely mount the sensor on a firm, stable surface or
support. An application which is subject to excessive vibration
or shifting may cause intermittent operation. Adaptors and
mounting brackets are available for a flexible installation that
may include vibration and shock while shifting. See
Accessories section for more details.
Wiring Diagrams
Cable connection is shown in the following diagrams. Pin
numbers correspond to an M12 or M8 male connector on the
sensor.
1
4
2
4
1
3
2
3
M12 Male
M8 Male
PNP Models with Complementary Outputs
PNP Models with
Complementary Outputs
Brown (1)
+
LO
Black (4)
Load
DO
White (2)
Load
Blue (3)
Transmitted Beam Emitter
Brown (1)
+
Black (4)
Blue (3)
— For normal operation, black wire (pin 4) needs no connection. To disable light source, connect
black wire (pin 4) to +V.
2
NPN Models with
Complementary Outputs
Brown (1)
+
DO
White (2)
Load
LO
Black (4)
Load
Blue (3)

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