Q60laf series laser adjustable-field sensors, Overview, Adjustable-field sensing – theory of operation – Banner Q60 Background Suppression Series User Manual

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P/N 114348

Q60LAF Series Laser Adjustable-Field Sensors

Banner Engineering Corp.

•

Minneapolis MN, U.S.A.

www.bannerengineering.com • Tel: 763.544.3164

Overview

The Q60LAF sensor is a full-featured adjustable-field sensor. These adjustable-

field sensors are able to detect objects of relatively low reflectivity, while ignoring

other objects in the background (beyond the cutoff point). The cutoff distance is

mechanically adjustable, using the 2-turn adjustment screw (Figure 1). A rotating

pointer indicates the relative cutoff position. (The indicator moves clockwise to show

increasing distance.) The collimated laser emitter produces a small, bright spot,

allowing easy alignment and precision sensing of relatively small objects at long

range.
Two push buttons (ON Delay and OFF Delay) are used to set the output delay options,

to toggle between light and dark operate modes and to lock out the push buttons for

security purposes. For 10 to 30V dc models, these functions also may be accomplished

using the remote wire.
Seven LED indicators show, during RUN mode, the sensor configuration and

operating status. During Delay Configuration, 5 of the LEDs combine to form a single

light bar that indicates relative ON or OFF delay time.

Adjustable-Field Sensing – Theory of Operation

In operation, the Q60LAF compares the reflections of its emitted light beam (E) from

an object back to the sensor’s two differently-aimed detectors R1 and R2 (see

Figure 2). If the near detector (R1) light signal is stronger than the far detector (R2)

light signal (see object A, closer than the cutoff distance), the sensor responds to the

object. If the far detector (R2) light signal is stronger than the near detector (R1) light

signal (see object B, object beyond the cutoff distance), the sensor ignores the object.
The cutoff distance for Q60LAF sensors is adjustable from 200 to 1400 mm

(8" to 55") for Class 1 laser models, and 200 to 2000 mm (8" to 80") for Class 2 laser

models. Objects lying beyond the cutoff distance are ignored.
In the drawings and discussion on this page and page 4, the letters E, R1, and R2

identify how the sensor’s three optical elements (Emitter “E”, Near Detector “R1”,

and Far Detector “R2”) line up across the face of the sensor. The location of these

elements defines the sensing axis (see Figure 3). The sensing axis becomes important

in certain situations, such as those illustrated in Figures 7 and 8.

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Figure 1. Q60LAF features

Figure 3. Q60 sensing axis

Lenses

Object

Object B

Background

Sensing

Range

Cutoff

Distance

Receiver

Elements

Near

Detector

Far

Detector

Figure 2. Adjustable field sensing concept

Receiver
Elements

Emitter

Sensing

Axis

When an object approaches from the side, the most reliable
sensing usually occurs when the line of approach is parallel
to the sensing axis.