A-198

Standard Photoelectric Sensors

Application

Short-distance, small spot type

Long-distance type

Features

Principles for Glossiness Detection by FAO

First, the light from a red LED passes through a polarizing fil-

ter so only the S wave is emitted.

If the detectable object is glossy, the S wave is reflected reg-

ularly and is transmitted as is to the Fiber Receiver 1.

If the detectable object is not glossy, there is more diffuse re-

flection, thus the polarization direction is randomized and a P

wave is generated.

The S and P waves are divided by the FAO (special polarized

beam splitter), the waves travel to their respective fiber receiv-

ers, and the variation in the glossiness is determined by com-

paring the two received signals.

Fuzzy Teaching Function Backs up Stable Detection

Supported by the fuzzy teaching function if objects have no

difference in glossiness. If the glossiness difference goes be-

low than the minimum sensing lev-

el,

the

microprocessor

in

the

amplifier determines the discrimi-

nation means automatically.

Sensed by light energy difference

like an ordinary mark sensor.

(When 2-point teaching is selected)

Measures against Double Refraction

There are transparent films and transparent plastic objects that

change the direction of polarized light when it passes through

the transparent films and transparent plastic objects. This is

called double refraction. Using the optional rotary mounting

bracket (E39-L109), the sensor unit can be inclined 45 degrees

to take measures against double refraction.

(Example) Metal cylindrical object coated with transparent film

Detection of tacked labels

Detection of grease or adhesive on parts

Detection of pipe, can or similar joints

Detection of on-bottle labels insensitive to

distance variation or object inclination, en-

abling label detection on conveyor line.

Detection of shrink tubes Transparent shrink

tubes can be detected stable.

Detection of sealing tape

Received fiber 1

(S wave only)

Received fiber 2

(P wave only)

Polarized filter

FAO

Emission

S wave

only

Sensing

object

Emitter

Lens

S wave: vertical

P wave: parallel

Metal cylindrical

object coated with

transparent film

Sensing head

The object can be sensed smoothly when

the angle of the sensing head is either 0˚ or 45˚.

45

˚

Difference in

grossiness

Distinction means

Output

Difference in

light energy