09-Jul-25

page 2 of 6

LX Series Part-Sensing Light Curtain

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www.bannerengineering.com

LX Series optical crosshatch pattern

Emitter

Receiver

Theory of Operation

The LX Series light screen sensing system consists of two self-contained units: an emitter and a

receiver of equal size and sensing range. The emitter has multiple infrared LEDs spaced at 9.5

mm (0.38 in) increments, and the receiver has corresponding photodiodes. The emitter

sequentially fires each infrared LED. Multiple photodiodes in the receiver recognize each of the

emitted pulses; the result is a “cross-hatched” optical pattern. Optical synchronization enables 

the receiver to recognize light from each of the emitter LEDs.

The optical crosshatch pattern enables the LX system to detect targets of very small diameter,

and extremely thin, flat objects—as thin as a piece of paper or an envelope. For small-diameter 

objects, the sensing resolution is less effective at the exact center (see the minimum object

detection size specification) of the sensing range and at the extreme edges of the pattern (close

to the emitter and receiver faces); sensing should take place within the center 80 percent of the

range, as shown.

LX Series sensors are available in two ranges: short and standard. Short-range emitters and

receivers may be located as close together as 75 mm (3 in), with a maximum separation of 200

mm (8 in). Standard-range sensors may be separated 150 mm to 2 m (6 in to 6.5 ft) apart. Both

emitter and receiver must be either short-range or standard models, of the same length.

Detection sensitivity varies somewhat, depending on the distance between the sensors and the

position of the target object.

For closer-range applications, the working range of any sensor pair can be reduced by

connecting the sensor’s Select wire to 0 V DC to 2 V DC (see the sensing range specification).

The receiver output interfaces directly with DC loads or circuits up to 30 V DC, and offers both sinking (NPN) and sourcing (PNP) output

transistors. Outputs conduct whenever a beam is broken. A 5-millisecond pulse stretcher (OFF-delay) is included to improve interfacing

reliability.

Typical Applications. Typical applications for the LX Series include parts ejection verification and package detection on a conveyor.

Installation and Alignment

Reliable performance of the LX series light screen systems requires a simple alignment process. Mount the sensor in a location as free from

vibration as possible.

Sensors may be mounted using the accessory brackets (available separately) or using the T-slots in the sensor housings. After mechanical

alignment is completed, the sensors can be wired and power applied.

Wiring Diagrams

Wiring for the integral cable models

bk

gy

bn

bu

wh

10–30 V DC

shield *

Select **

Reduced

0–2 V DC

Load

Load

Normal

5–30 V DC

bk

gy

bn

bu

wh

10–30 V DC

shield *

Select **

Reduced

0–2 V DC

Normal

5–30 V DC

No Connection

No Connection

Receiver

Emitter

Loosely mount the emitter and receiver at their operating locations with their front panels opposite each other, and at approximately

the same level.

1.

Adjust the emitter position until the receiver detects alignment (the yellow LED turns OFF). For best alignment, position the emitter in

the middle of the positions that cause a clear receiver condition.

2.

Tighten the bracket hardware.

3.

Position a pencil or similar object within the sensing area to verify that it can be reliably detected throughout the sensing area.

4.