photoelectric sensors principles - mehatronik sistem€¦ · sensors with background suppression...

2.0.1

Only true specialistscan excel in any givenarea. This is whyBalluff has expandedits product range ofoptoelectronic sensors,which has always beendesigned to meet themost varied challenges.

We consider ourselvesas a partner and con-sultant for our custom-ers. We are constantlyimproving and ex-panding our productoffering, so that whenyou come to us you willfind the best solution.

The most significantnew additions are:

– mini.s(BOS 08M/BOS Q08M)

– Series BOS 5K– Series BOS 21M

(standard and specialsensors)

– Redesigned seriesBOS 18 KF/KW

– Distance sensors(BOD 63/BOD 26)

– Laser slot sensors(BGL)

– Angle sensors(BWL)

2.0.2 Applications2.0.8 Product overview2.0.14 Principles,

definitions

2.0

ContentsPhotoelectricSensors

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2.0.2

Application Examples

The application examplesare shown in simplified form.Complete part numbersare not provided for therecommended sensorssince the exact model willvary from application toapplication. Our applicationsassistance group will helpyou to find the optimalsolution.

Sensing size and contentsof containers

BOS 18M-..-1QB-... RetroreflectiveBOS R-1 ReflectorBOS 18M-..-1HA-... Diffuse with

HGA andadjustableswitchingdistance

The retroreflective sensor (1)indicates the presenceof the box. Boxes can becounted or the length of abox determined (from thepulse duration). The diffusesensor has backgroundsuppression (HGA) and itsrange is adjustable.It checks the contents ofthe boxes on the conveyorbelt.

Sensing stack height

BLS 15K-... EmitterBLE 15K-... Receiver

Each through-beam pairchecks a certain stackheight. Several sensors canbe mounted over each other.The sensing distance canbe up to several meters.The sensing accuracy in thevertical axis is just a fewmillimeters if the suppliedapertures are used.

Guiding a moveable stage

BLE 18M-... ReceiverBLS 18M-... EmitterBOS 18-BL-2 Slit aperture

The senors are arranged sothat the upper metal blockbreaks the light beam.When the block is removedfor processing, the beampath is open. The sensorgives a signal, and the stageis automatically raised by theheight of a block.

PhotoelectricSensors

2.0.3


Sensing a read mark

BOS 73K-.../ Base unitsBOS 74K-... for plastic

fiber opticsFIber optic BFO ... Fiber optic

A marking (light band) ona dark background (belt,tube, container etc.) canbe detected.Here a base unit for fiberoptics and a plastic fiberoptic cable are used.

Drill break monitor

BLS 18M-... EmitterBLE 18M-... ReceiverBOS 18-BL-2 Double slit

diaphragm forthru-beams

Broken drill detection froma distance of 2 meters canbe accomplished usinga through-beam system withdouble slit diaphragm. Drillslarger than approx. 2 mmdiameter can be checked.To detect even smaller drills(up to ∅ 0.1 mm), use alaser through-beam sensor.

Small parts detection

BOS 18M-... Diffuse withadjustablesensingdistance

BOS 18-PK-1 Plano-convex lens

BOS 18M-..-1HA-... Diffuse withbackgroundsuppression

Detection of small partswhile masking the back-ground is done using aBOS 18-PK-1 opticaladapter.For example, threads witha diameter of 0.1 mm couldbe sensed, whereby coloris not a factor. The sensingrange here is approx.0...13 mm. Longer rangescan be achieved by usingdiffuse sensors withbackground suppression.

Detecting a groove

BOS 18M-..-1PD-... Diffuse withadjustablesensingdistance

BFO 18-... Fiber opticcable

To sense a groove ona bearing pillow, a diffusesensor is adjusted withfiber optic cable so that thebearing pillow is alwaysdetected.The groove interrupts thebeam (no reflection). Theswitch changes its outputcondition.

2.0


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2.0.4


Level detection intransparent containers

BOS 18M-..-1PD-... DiffuseBFO 18A-... Fiber optics

A diffuse sensor with fiberoptic attachment is used asa through-beam to monitorthe level in a transparentcontainer (cylinder). If thereis no liquid at the height ofthe sensor, the light beam isnot interrupted and insteadarrives at the receiver. If theliquid is high enough, thelight beam is deflected awayfrom the receiver and theswitch changes its state.

Differentiatingvarious diameters

BOS 18M-..-1HA-... Diffuse withHGA andadjustableswitchingdistance

To detect various shaftdiameters, a diffuse sensorwith background suppres-sion (HGA) is calibrated sothat it switches when thediameter is large. If a smallerdiameter appears at thesensing station, this isinterpreted as "background",and the sensor does notswitch.

Checking contentsof a package

BLE 18M-... ReceiverBLS 18M-... EmitterBOS 18-BL-1 Diaphragm

for through-beams

A through-beam versionis used to check thecontents of the packaging.Emitter and receiver arearranged such that the lightbeam passes through thepackaging.If the package is empty,the intensity is sufficient toilluminate the receiver.If however the packagingcontains product, thecontents interrupts thisbeam from the emitter andthe switching output isactivated.

Slack control

BLE 18M-... ReceiverBLS 18M-... Emitter

Two through-beam sensorscan be used to control theguiding of a roller conveyor.The through-beams arearranged above each otherso that at optimum slack thelower light beam is clear andthe upper beam interrupted.If both light paths are clear,more roll tension is needed.If both are interrupted, thereis too much material (slack)present.


2.0.5


Parts positioning

BOS 26K-..-1LHB-... Laser sensorwith HGA andadjustableswitchingdistance

To position a turned part youcan check for the presenceof a slot. A laser sensorwith background suppres-sion is calibrated so that itrecognizes the surface of theturned part. If the light beamstrikes the slot, the light isreflected back to the sensorat a different angle. Theswitch recognizes this asa background signal anignores it, i. e. changes itsswitching state.

Level control of granulesin small packages


fiber opticsBFO ... Fiber optics

A group of sensors monitorsthe contents of a wholerow of small packets on aconveyor belt. The plasticfiber optics cable can beuser-cut to the desiredlength. Standard suppliedlength is 2 meters.

Defect inspectionof workpieces



Multiple sensors with fiberoptics attachmentssimultaneously check diffe-rent features of a workpiece.Only if all holes, screws,tolerances and surfacequalities are present, will theworkpiece be accepted.Later failures and downtimeare thus avoided.

Detecting a bead ona cam shaft

BOS 18M-..-1PD-... Diffuse withadjustablesensingdistance

BFO 18-... Fiber opticscable

To determine whether abead is present or not,a fiber optics attachment isused with a diffuse sensor.The fiber optic is arrangedon a level parallel to the camshaft. If a bead is present,the light beam is interrupted.With no bead, the beampath is free.

2.0


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2.0.6


Part sorting Thread checking Packaging inspection Countingtransparent bottles

BLS 6K-... EmitterBLE 6K-... Receiver

To sort out parts whichvary in height, a through-beam sensor can be used.By pressing a button youcan calibrate the BLS/BLE6K so that the taller partinterrupts the light beam andcan be rejected. The teach-in proce-dure allows youto make this setting rapidlyand adjust it to changingrequirements.

BOS 6K-.../ RetroreflectiveBOS 21M-... for glass

sensing

Reliable sensing of transpa-rent objects, which absorbvery little light, is best doneusing retroreflective sensorswith low hysteresis.Using the BOS 6K withteach-in calibration you caneven change the calibrationsetting while the process isrunning. It is no longer nec-essary to stop the process,since the sensors can forexample be calibrated duringthe warm-up phase.

BLS 12M-... EmitterBLE 12M-... Receiver

To check whether thepackaging is correctlyclosed, a through-beamsensor is configured so thatthe light path is just abovethe packaging. If thepackaging is not correctlyclosed, the obstructing lidinterrupts the light obeamand the through-beamsensor signals this.

BOS 73K-.../ Basis unitBOS 74K-... for plastic


Prior to assembling nuts,a check needs to be madeto determine whetherthreads are present or not.If the threads are present,they will reflect the light backto the fiber optics and thesensor will switch.If no threads are present,total reflection will becreated on the smooth wallof the hole and no light willbe reflected back to thefiber optics; the sensor willnot send a switching signal.


2.0.7


Final inspection: labels,caps

Checking for correctquantity

BOS 26K Diffuse withbackgroundsuppression

Diffuse sensors with back-ground suppression areused to check in detailwhether an assembly pro-cess has been completed.These sense small objectswith high precision andare not misled by differentcolors. Using laser sensorswith HGA backgroundsuppression allows evenfiner details to be detected.

BKT Contrastsensor


As final inspection of dishdetergent bottles a checkmust be made to determinewhether the label and capare attached. A contrastsensor is used for the labelinspection.This distinguishes betweenthe relative reflectivity of thelable and the bottle.The cap is detected usinga diffuse sensor with back-ground suppression.Advantage of backgroundsuppression: if no cap ispresent, the threadedclosure can be suppressed.

Circuit board inspection/positioning

BOS 15K Diffusefocused

BOS 26K Laser diffusesensor withbackgroundsuppression

To bring the circuit boardto a particular inspectionposition, a focused diffusesensor (1) is used. Thecircuit board crosses thelight path of the sensorexactly at its focal point, thusenabling maximum precision.The small light spot from thelaser diffuse sensor (2) andthe background suppressioncan be used to checkwhether even small compo-nents are present on theboard.

Checking for caps


BOS 18M Diffuse withbackgroundsuppression

Depending on installationcircumstances and therequired switching distance,a wide variety of diffusesensors with backgroundsuppression can be em-ployed. For tight mountingspaces the BOS 6K is ideal.If maximum resolution isrequired, the BOS 18M isthe best choice; and ifgreater sensing range isneeded, sensors from theseries BOS 26K, BOS 36Kor BOS 65K will solve theproblem.

2.0


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BOS 18MPotentiometer

Metal

16 m

4 m

2 m

100 mm, 200 mm,400 mm, 1 m

10...120 mm,40...120 mm

depending onfiber type

10...30 V DC,20...250 V AC

PNP/NPNNO/NC

Connector/cable

–20...+60 °C

IP 65/IP 67

infrared/red

M18×62...95 mm

2.1.18

Type

Housing material

Through-beamEmitter/receiver

Retroreflective

Retroreflectivewith polarizing filter

Diffuse

Diffuse withfocused light beam

Diffuse withbackground suppression

Fiber opticbase unit

Supply voltage

Outputfunction

Connection

Operating temperature

Protection per IEC 60529

Light type

Dimensions

Unique features

see starting page

Product Overview

2.0.8

Range

BOS 12M

Metal

0...5 m

0...1.5 m

100 mm, 200 mm,400 mm

0...23 mm,10...60 mm

10...30 V DC

PNPNO/NC

Connector/cable

–20...+60 °C

IP 67

infrared/red

M12×65...74 mm

2.1.8

BOS 18MTeach-in

Metal

16 m

2 m

400 mm

10...30 V DC

PNPNO/NC

Connector

–15...+55 °C

IP 67

infrared/red

M18×70...72 mm

Alarm output

2.1.28

BOS 18MLaserMetal

0...50 m

10...30 V DC

PNPNO/NC

Connector

–15...+55 °C

IP 65

Laser

M18×79...85 mm

also as rightangle,

focusable

2.1.30

BOS 18MR

Metal

0...16 m

0...2 m

400 mm

10...120 mm,40...120 mm

10...30 V DC,10...36 V DC

PNPNO/NC

Connector

–25...+55 °C

IP 67

red

M18×78.6...82 mm

2.1.34

BOS 18E

Stainless steel

16 m

4 m

2 m

100 mm, 200 mm,400 mm

40 mm

10...30 V DC

PNPNO/NC

Connector

–20...+75 °C

IP 68

infrared/red

M18×70 mm

Tighter sealing,glass or plastic

fiber optics

2.1.38

BOS 08M

Metal

0...1.1 m

25...550 mm

0...55 mm

10...30 V DC

PNPNO/NC

Connector/cable

–10...+60 °C

IP 67

red

M8×50...57.5 mm

2.1.4


mini.s

Technical data

Product Overview

2.0.9

BOS 18KF

Plastic

0...20 m

0.1...4.5 m

0...100 mm,0...700 mm

50...100 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–25...+55 °C

IP 67

infrared/red

M18×67...81.5 mm

flexiblemountingoptions

2.1.44

BOS 18KFLaserPlastic

0...60 m

0.1...16 m

0...350 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–10...+50 °C

IP 67

Laser

M18×71.5...81.5 mm


2.1.48

BOS 18KW

Plastic

0...15 m

0.1...3 m

0...80 mm,0...400 mm

50...100 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–25...+55 °C

IP 67

infrared/red

M18×79...93.5 mm


2.1.54

BOS 18KWLaserPlastic

0...50 m

0.1...9 m

0...250 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–10...+50 °C

IP 67

Laser

M18×83.5...93.5 mm


2.1.60

BOS 30M

Metal

0...2 m


10...30 V DC

PNP/NPNNO/NC

Connector

–20...+60 °C

IP 65

infrared

M30×92...108 mm

2.1.68

BOS 6K

Plastic

6 m

0.5 m, 2.5 m

5...300 mm

25...100 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–20...+60 °C

IP 67

infrared/red

32×20×12 mm

teach-in

2.1.84

2.0


BOS Q08M

Metal

0...1.1 m

25...550 mm

0...55 mm

10...30 V DC

PNPNO/NC

Connector/cable

–10...+60 °C

IP 67

red

8×8×44...59 mm

2.1.72

BOS 5K

Plastic

0...10 m

0.1...4 m

0...900 mm,50...200 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–25...+55 °C

IP 67

infrared/red

19.5×31.5×10.8 mm

2.1.76

www.balluff.de

mini.s

BOS 21M

Metal

0...20 m

0.1...8 m,0...2 m, 0...4 m

0.01...1 m,0.05...2 m

20...200 mm,70...200 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–25...+55 °C

IP 67

infrared/red

41.5×49×15 mm

Glass sensingthrough-beam with

auto-collimation

2.1.98

Type

Housing material

Through-beamEmitter/Receiver

Retroreflective

Retroreflectivewith polarizing filter

Diffuse

Diffuse withfocused light beam


Fiber opticbase unit

Distance sensor

Supply voltage

Outputfunction

Connection



Light type

Dimensions

Unique features

see starting page

Product Overview

2.0.10

Range

BOS 15K

Plastic

5 m

2 m

100 mm,500 mm

12 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–15...+55 °C

IP 66

infrared/red

29×44×13 mm

also with axiallight exit

2.1.92

BOS 21MLaserMetal

0...60 m

0.1...20 m

0...600 mm

50...100 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–10...+50 °C

IP 67

Laser

41.5×49×15 mm

2.1.102

BOS 25K

Plastic

0...5 m

0...4 m

1...900 mm

50...250 mm

10...30 V DC,15...264 V AC/DC

PNP/NPNNO/NC

Connector/cable

–15...+55 °C

IP 65

red

50×50×18 mm

2.1.110

BOS 26K

Plastic

0...5.5 mm

30...300 mm,150...600 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–20...+60 °C

IP 67

infrared/red

50×50×17 mm

LS with auto-collimation

2.1.116

BOS 26KLaserPlastic

0...2.5 mm,0...12 m

30...150 mm,50...300 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–15...+45 °C

IP 67

Laser

50×50×17 mm

LS with auto-collimation

2.1.118

BOS 6KLaserPlastic

0.1...1 m

20...60 mm,30...110 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–20...+60 °C

IP 67

Laser

20×30×12 mm

teach-in

2.1.86


Technical data

Product Overview

2.0.11

BOS 35K

Plastic

0...8 m

0...4 m,0.25...8 m

0...200 mm,0...400 mm

10...30 V DC

PNPNO/NC

Connector

–5...+55 °C

IP 67

infrared/red

50×60×15 mm

fully potted

2.1.124

BOS 36K

Plastic

0...50 m

0.1...8 m

10...2000 mm

100...500 mm

10...30 V DC

PNPNO/NC

Connector

–10...+55 °C

IP 66

infrared/red

55×65×20 mm

rotatableconnector

2.1.130

BOS 65K

Plastic

0...50 m

0.3...8 m

50...2000 mm

200...1100 mm

10...30 V DC,17...264 V AC/DC

PNP/NPNNO/NC

Connector/terminal chamber

–20...+55 °C

IP 67

infrared/red

73×85×32 mm

Time functions,alarm output

2.1.136

BOS 15K

Plastic


10...30 V DC

PNP/NPNNO/NC

Connector/cable

–15...+55 °C

IP 66

red

29×54×13 mm

2.2.4

BOS 20K

Plastic


10...30 V DC

PNP/NPNNO/NC

Connector/cable

0...+60 °C

IP 65

red

30×60×13 mm

teach-in

2.2.6

BOD 6K

Plastic

20...80 mm

20...80 mm

15...30 V DC

analogPNP NO/NC

Connector/cable

–20...+60 °C

IP 67

red

20×32×12 mm

teach-in

2.2.28

2.0


BOS 73K

Plastic


11...26 V DC

PNPNO/NC

Connector/cable

–25...+55 °C

IP 54

red

30×60×9 mm

with display

2.2.8

BOS 74K

Plastic


10...30 V DC

PNP/NPNNO/NC

Connector/cable

–10...+60 °C

IP 66

red

41×69×12 mm

2.2.10

www.balluff.de

BOD 66M

Metal

100...600 mm

100...600 mm

18...30 V DC

analog/PNPNO

Connector

–20...+50 °C

IP 65

red

73×90×30 mm

2.2.40

Type

Housing material

Distance sensor


Contrast sensor

Luminescence sensor

Color sensor

Slot sensor

Angle sensor

Dynamic optical window

Supply voltage

Outputfunction

Connection



Light type

Dimensions

Unique features

see starting page

Product Overview

2.0.12

Range

BOD 63MLaserMetal

500...6000 mm

500...6000 mm

15...30 V DC

analog/PNPNO

Connector

–10...+55 °C

IP 65

Laser

90×70×35 mm

2.2.36

BOD 66MLaserMetal

200...2000 mm

200...2000 mm

18...30 V DC

analog/PNPNO

Connector

–20...+50 °C

IP 65

Laser

73×90×30 mm

2.2.42

BKT 6K

Plastic

40...150 mm

10...30 V DC

PNP/NPNNO/NC

Connector/cable

–20...+60 °C

IP 67

Laser

20×30×12 mm

focusedlight beam

2.2.46

BKT 21M

Metal

19 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–25...+55 °C

IP 67

white

42.5×50×15 mm

2.2.48

BKT M

Metal

9 mm (18 mm)

10...30 V DC

analog/PNP/NPNNO/NC

Connector/cable

–10...+55 °C

IP 67

red/green

62×83×31 mm

Interchangeableoptics

2.2.50

BOD 26KLaserPlastic

45...85, 30...100,80... 300 mm

30...100 mm,80... 300 mm

18...28 V DC18...30 V DC

analog/PNPNO/NC

Connector/cable

–10...+60 °C

IP 67

Laser

50×50×17 mm

adjustablemeasuring range

2.2.30


Technical data

Product Overview

2.0.13

BLT 21M

Metal

0...40 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–10...+55 °C

IP 67

UV

42.5×50×15 mm

2.2.54

BLT M

Metal

9...18 mm

10...30 V DC

analog/PNP/NPNNO/NC

Connector

–10...+55 °C

IP 67

UV

62×83×31 mm

other rangeswith added

lenses

2.2.56

BFS 26K

Plastic

12...32, 15...30,18... 22 mm

12...28 V DC

3 × PNPNO

Connector

–10...+55 °C

IP 67

white

50×50×17 mm

variouslight spot sizes

2.2.60

BGL

Metal

5, 10, 20, 30, 50, 80,120, 180, 220 mm fixed

10...30 V DC

PNP/NPNNO/NC

Connector

–10...+60 °C

IP 67

red

depending on type

stackable

2.2.64

BGLLaserMetal

30, 50, 80,120 mm

10...30 V DC

PNP/NPNNO/NC

Connector

–10...+60 °C

IP 67

Laser

depending on type

stackable

2.2.68

BOWA

Metal

40×80, 80×80,120×80 mm fixed

10...30 V DC

PNPNO

Connector

–10...+55 °C

IP 65

infrared

depending on type

dynamicmeasurement

2.2.78


BGL 21

Metal

2 mm fixed

10...30 V DC

PNP/NPNNO/NC

Connector

0...+55 °C

IP 65

red/green

90×26×20 mm

for label sensing

2.2.71

BWL

Metal

22×22, 43×43,42×62 mm

10...30 V DC

PNPNO

Connector

–10...+60 °C

IP 67

infrared

depending on type

2.2.74

2.0

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Wire colorsdesignationper DIN IEC 60757

BN brownBK blackBU blueOG orangeWH whiteRD redGY gray

... in the receiver (PNP opencollector – 30 mA). Thereceiver is equipped with analarm output. It acts asa warning signal when thefunction is affected by con-tamination or mechanicalmaladjustment.The alarm output is activatedwhen the receive signal ispresent in the alarm range

stable

unstable

stable

Switchingthreshold

Stability(green LED)

Alarm

The alarm output ...(for series BOS 15,BOS 18 teach-in, BOS 25,BOS 65, BOS 74)

Auto-collimation Emitter and receiver use acommon lense. The emitterlight passes through thebeam splitter and the lens tothe reflector. The reflectorbounces the emitter lightback to the lens. This gives

retroreflective sensors havingauto-collimation a small,round beam profile.And there is another benefit:no dead area for sensingand for the reflector, bettersmall parts detection, andthe switching characteristic

Analog output A sensor with an analogoutput does not switch at aparticular target distance.These devices have ananalog output with andistance-dependent output

signal. The output voltagecorresponds to the objectlocation within the sensingrange.These systems operate onthe same principle as

sensors with backgroundsuppression. They generatea linear output signal withina certain range (measuringrange)

... is the time which thesensor requires for actuation

when the target objectleaves the sensing zone, at a

Turn-off delay ... transmission efficiency factorof 0.5.

Dark-onper DIN 44030

Consumerswitched onswitched off

Amplifierconductingnon conducting

Light receivernon-illuminatedilluminated

Through-beam Through-beam sensorsconsists of separate emitterand receiver units whichmust be aligned on oppositesides of the sensing path.A target interrupts the lightbeam and causes the

receiver to switch regardlessof the surface character-istics. Through-beam ver-sions are best in unfavorableconditions (e.g. dust,moisture, oil).

for a defined length of time.For series BOS 18M teach-inand BOS 65K the entire

family, including diffuse andretroreflective, is equippedwith an alarm.

Principles,Definitions

2.0.14

Target

Emitter Receiver

... is the response time asensor needs if the target

object enters the sensingzone, with the transmission

Turn-on delay ... efficiency at a factor of 2.

is independent of theapproach direction.

Receiver

EmitterBeam splitter

Detectionarea

LensReflector


Ranges of up to 50 m canbe achieved.

Color sensing Sensors for color recognitiondetect objects based ontheir color. The sensor is

calibrated so that itrecognizes objects having acertain color.

Objects with different colorsdo not generate a switchingsignal.

Focusing To achieve a smaller lightspot, the light beam from theemitter is focused usinglenses. Focusing and theresulting light spot allow the

switch to better detect smallparts and details.Focusing is often used withretroreflective sensors aswell as with diffuse sensors

... is the portion of lightwhich impinges on the

Ambient light ... receiver, but does notoriginate from the emitter.

in conjunction withbackground suppression.

Slot sensor Slot sensors are through-beam designs in which theemitter and receiver arearranged opposing in aU-shaped housing. The fixedhousing makes alignmentand the electrical connectioneasier. Different ranges are

available by selecting diffe-rent housing configurations.Slot openings of between5 and 120 mm in variousstep sizes are avail-able.The built-in potenti-ometerand diaphragms allow youto adjust the slot sensors

easily for detecting partsdown to a diameter of0.5 mm.

Gray scale shift Gray scale shift is theswitching distance differencewhen calibrating usingdifferent object reflectivities.The sensor is calibrated for adistance using a Kodak gray

card having 90 % reflection.A Kodak gray card having18 % reflection is used andthe resulting distancemeasured. The differencebetween these two

switchpoints in % is referredto as the gray scale shift.The smaller the gray scaleshift the less color-dependent the sensor willbe.

2.0.15


Polyurethane jacket

– Temperature T = +85 °C– excellent

chemical resistance– flexible– no embrittlement from oils

and cooling emulsions.

Corrugated metal tube,silicon jacketed– Temperature T = +150 °C– highly flexible– tread-resistant– can be sterilized.

Metal jacket

– Temperature T = +250 °C– resistant to hot chips– flexible– tread-resistant.

Optical conductors aremade of glass or plastic witha diameter of as little as50 µm and bunched inbundles of several hundredindividual fibers to formso-called fiber optics. Thefiber ends are ground andpolished to meet the qualitycriteria of the opticalindustry. The individual fibershave an extremely thin,permanently adhering lubri-cant coating which reducesfriction with the outer jacket

and between the fibers, sothat fiber breaks are virtuallyunheard of even underconstant bending. Thetransmission properties areguaranteed over a longerperiod of time.The ends of the bundles arepotted with the connectionsleeve and the jacket. Ballufffiber optics thus have anIP 67 rating (IP 65 for metaljacket). Moisture and ag-gressive media cannot hurteither the fibers or the slide

coating, so the optical prop-erties remain unaffected.

This design distributes axialpull forces evenly over allthe fibers and protects theindividual fibers from exces-sive pull loads

Fiber optics

Consumerswitched onswitched off

Light receiverilluminatednon-illuminated

Light-onper DIN 44030

Amplifierconductingnot conducting

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...is the distance betweenthe switchpoints for a target

Hysteresis H ... approaching and thenreceding from an optoswitch.

Kodak gray card The "standard target" foroptoelectronic sensors is theKodak gray card. This is acardboard sheet whose

surface has a defined degreeof reflectivity. The sidewith 90 % reflection is usedfor determining the range of

diffuse sensors, and the sidewith 18 % for determining thegray scale shift.

Short circuit protection The output leads can beconnected to the wrongpotential without destroying

the sensor. Together withtheir polarity reversalprotection, these sensors

are completely protectedagainst miswiring.

Lasers, laser class The purpose of laserprotection classes is toprotect persons from laserradiation by specifying limitvalues. Based on this thelasers used are classifiedaccording to a scale whichreferences the degree ofhazard.The calculations used forthe classification and the re-sulting limit values are de-scribed in EN 60825-1/94.The grouping is based on acombination of output powerand wavelength, taking into

account duration of theemission, number of pulsesand angle opening.

Balluff sensors operate inthe following laser protectionclasses

Class 1: harmless,no protective measuresnecessaryClass 2: low power, eyelidreflex is sufficient protection.

For devices in Class 1 and2 the eye protects itself fromlooking too long into thebeam through the eyelidreflex. Appropriate warninglabels must be affixed to thedevice and in some casesto the machine in whichthe laser is used. No othermechanical or opticalprotection measures arerequired. When usingdevices from class 1 and 2,no person responsible forlaser protection needs to bepresent.

Correction factors(for diffuse types)

For objects with varyingreflection characteristics, therange can be determined byusing the correction factorsshown. See the adjacenttable.

Factor1

1.2...1.61.2...1.8

10.60.50.40.30.1

Object, surfacePaper, white, matte 200 g/m²Metal, shinyAluminum, black anodizedStyrofoam, whiteCotton fabric, whitePVC, grayWood, roughCardboard, black, shinyCardboard, black, matte


2.0.16

Background suppression(HGA)

HGA allows objects within acertain switching distance tobe detected without beingaffected by a reflectingbackground and virtuallyindependent of objectreflectivity (color or surfacetexture).HGA is realized by allowingthe beam cones of theemitter and receiver tointersect. This results in a

division of the field of viewinto an active area and thebackground. In addition, bydividing the receiver intoat least two adjacent areas(e. g. by using a dual diodeor a PSD element) and bymeans of a geometricarrangement (triangulation),the actual position of theobject within the sensingrange can be determined.

These two design featuresalow the object to be reliablydistinguished from thebackground. Diffuse sensorswith HGA are characterizedby low gray scale shift andhysteresis.


Light refraction Light beams experience achange in direction at thesurfaces of two opticalmedia with differing opticaldensity (e. g. glass/air),i. e. they are refracted.The degree of refraction isdependent on the quotientsof the optical densities nnnnn ofboth media and on the angleof incidence �to the optical axis.

Light transmission bytotal reflection

Without the above describedtotal reflection at boundarylayers, fiber optics of today'squality would not beattainable. They consist of acylindrical, light-conductingcore and a surroundingthin-wall jacket. The opticaldensity of the core is greaterthan that of the jacket. Alight beam is always totallyreflected at the junctionbetween core and jacket,and can therefore neverleave the core in a radial

2.0.17


If a light beam travels from adense medium nnnnn into athinner one n'n'n'n'n', its coursethere will show a greaterangle ��'''''. Above ��crit.crit.crit.crit.crit. (criticalangle, at which the deflected

beam runs parallel to theboundary layer), however, itre-enters the medium withdensity nnnnn, i. e. here there istotal reflection.

Total reflection

direction. Theoretically thelight is not weakened bythese reflections; however,contamination and smalldefects both in the corematerial as well as theboundary layer do causelosses (attenuation) and

effectively limit the conductorlength over which reliableinformation can bepropagated.

Diffuse Diffuse types have theemitter and receiver inte-grated into a single housing.Orientation to the target isnot critical.A target object (e. g. astandard target which is90 % reflective) bounces apart of the light from itssurface back to the receiver.

Once the standard targetenters the effective beam(see illustration), a change inthe output switching stateoccurs.The sensing range dependsupon size, shape, color andsurface characteristics ofthe reflecting target object.Using a Kodak gray cardwith 90 % reflectivity (like

reflected, or even scattered.Pulsed infrared LED's arenormally used as the emitter,and phototransistors as thereceiver. The output signal isfor the most part indepen-dent of the ambient lightconditions, since visible lightcan be easily filtered out. Incritical sensing applications,diffuse sensors or through-beam systems with red lightLED's are used, since the

...is used in numerous areasof technology and ineveryday life in controllingapplications. Generally achange in the light intensityin an optical beam (betweenemitter and receiver) causedby a target object isevaluated. Depending on theproperties of this object andthe characteristics of theoptical beam, the light beamis either interrupted or

Light as a sensormedium ...

light beam and the sensingpoint can be visually seenand more easily adjusted.Balluff offers three sensortypes for the variousapplication requirements:diffuse, retroreflective, andthrough-beam sensors.

Emitter/Receiver

EffectivebeamActual beam

Standard target90 % reflective

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white paper), ranges up to2 m can be obtained.

mirror, provide a selectivebarrier against the reflected"object light" while stillallowing the "reflector light"to pass freely.

reflected "object light" from"reflector light". Falseswitching can therefore notbe ruled out. Balluff retro-reflective sensors areavailable with polarizationfilters, which together with aBalluff reflector, which isan "optically active" prism

A part of the emitter light inretroreflective systems isreflected directly back to thereceiver from target objectswith shiny surfaces, e. g.stainless steel, aluminum ortinplate. Simple retro-reflective systems can thusnot reliably distinguish

Polarizing filtersWhen do you need them?

How do they work? Light consists of a number of"single beams", all of whichoscillate sinusoidally aroundtheir propagation axes.Their polarization planes arehowever independent ofeach other and can assumeany angle orientation (seefigure). When they meeta polarizing filter (fine gridlines), only the beamsoscillating parallel to the grid

plane are allowed to pass,and those oscillating at rightangles to the grid are can-celled out. Of all the otherpolarization planes, only theportion which consistsof parallel components isallowed to pass.

... for blocking reflected light

On the other hand, the lightreflected from the triplemirror, with its polarizationplane rotated by 90º asdescribed above, is allowedto pass unhindered by thisfilter.

... for reliable detection ofreflecting target objects

Behind the filter, the lightonly oscillates parallel to thepolarization plane. Forthis light, an additional 90ºrotated polarizing filterbecomes an impassablebarrier.


2.0.18

With a 90º rotated polarizingfilter in front of both theemitter and receiver of aretroreflective system,you can therefore preventreflected light from areflecting target object fromfalse triggering the signal ofthe photoreceiver.

The receiver of a retro-reflective system is therebyfully shielded even whena reflecting target objectenters the beam, so that theobject is still reliablydetected.

... is 35...85 %(non-condensing).

Max. humidity ...

Luminescence To sense invisible marks onobjects, so-calledluminescent materials(contained in special chalks,inks, paints etc.) are usedwhich can only be madevisible under ultraviolet (UV)

light. The fluorescent ma-terials convert the invisibleUV light (short wavelength,here 380 nm) into visible light(between blue 450 nm anddark red 780 nm).

This effect is called photo-luminescence.The visible light can then bedetected as usual by thereceiver component of thesensor.


Depending on the surfacecomposition of the object,one of three types of

ReflectionWhat is it? Light beams propagate in

free space in a straight line.Upon striking an object, theyare reflected back.

... occurs with a highly shiny(reflecting) surface. Theangle of incidence is therebythe same as the angle ofreflection (εI = εE ).

Total reflection ...

Retroreflexion ... ... is caused by two mirrorsat vertical angles to eachother. The double reflectioncauses a light beam to bebounced back in the samedirection. The angle ofincidence can thus bealtered in a relatively widerange.

2.0.19


reflection occurs: totalreflection, retroreflection,and diffuse reflection.

... occurs with an unevenand rough surface. It can bedemonstrated with a varietyof poorly reflecting andvariously oriented miniaturemirrors.Infalling light is widely"scattered" from such asurface. The reflection losses

are higher the darkerand more matte finished thesurface is.

Diffuse reflection ...

Retroreflective

ReflectorEmitter/Receiver

Target

Retroreflective types havethe emitter and receiver inte-grated into a single housing.A reflector on the oppositeside of the beam bouncesthe emitter's light back tothe receiver. A target objectinterrupts the reflected lightbeam and causes a changein the output signal.

With reflective surfaces it isrecommended that the lightreflected from the object befiltered out using a polarizingfilter in front of the receiver,in order to prevent anypossible spurious signals.

The two-dimensionalprinciple of retroreflectiondescribed above can becarried over to a spatialsystem with three mirrorswhich are oriented at rightangles to each other (onecorner of a cube standingon its point). A light beamentering this system is

totally reflected by all threesurfaces and exits parallel tothe infalling beam.Triple mirrors are said to be"optically active", becausethey also rotate the polar-ization level of the reflectedlight beam by 90º. Thischaracteristic is needed –together with a polarization

Reflectorsoptically active triple mirrors

Six triple-mirrors arecombined into a hexagonand arranged in honeycombfashion. Their orientationwith respect to the lightbeam is then totallyuncritical.

These are generally made ofplastics with high opticaldensity, injected as sheets orpressed into flexible tape.

filter (see page 2.0.18) – toprovide reliable detection ofreflecting objects using ret-roreflective sensor systems.

The reflection losses are inthe ideal case negligible.

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Switching distanceSwitching distance s ... ... is the distance between

the standard target and the"sensing face" of the lightsensor for causing a signalchange (per EN 60947-5-2).

... is a switching distanceparameter which ignoresmanufacturing tolerances,random variance, andexternal influences liketemperature and voltage.

Actual switchingdistance sr ...

... is the switching distanceat rated voltage Ue takinginto account manufacturingtolerances at rated ambienttemperature(T = +23 °C ±0.5).

Useful switchingdistance su ...

... is the permissibleswitching distance withinspecified voltage andtemperature ranges(0.80 sn ≤ su ≤ 1.20 sn).

Blind zone ... ... is the permissibleswitching distance withinspecified voltage andtemperature ranges(0.80 sn ≤ su ≤ 1.20 sn).

Detection range sd ... ... is the area within whichthe switching distance of anopto switch can be set usinga standard target.

Rated switchingdistance sn ...

sn

sr

su

sd

120 % 80 %

Blin

e zo

ne

0 %

Sen

sing

fac

eKod

ak g

ray

card

135 % 100 %

Emitter light Optical sensors generallyuse the following emittercomponents:

Red light-LEDVisible light, good as analignment aid and for sensoradjustment.Infrared-LED (IR)Invisible beam with highenergy.

Red light laserVisible light whose physicalproperties make it ideal forsmall parts detection andlong ranges.


2.0.20

Teach-in Sensor settings on teach-insensors do not have to bemade using a potentiometeror slide switches; everythingis controlled with the push ofa button. The microcontrollerintegrated into teach-insensors allows the entiresetup sequence to becontrolled by pressing the

button. The use of definedcalibration steps also meansthat the sensor cannot becalibrated for an unreliablezone. The microcontrolleralso assumes control of thecontamination indicator andthe contamination output.A variety of Balluff teach-insensors also provide the

option of remote operation,whereby the teach-in cal-ibration process is initiated"externally" through a cableline.


2.0.21


... is the switchpoint shiftwith changing temperature in% of sr.

Temperature drift ...

... for the emitter interruptsthe light pulses from theemitter and allows thefunction of emitter andreceiver to be checked.When using Test+, Test–must be at 0 V, when usingTest–, Test+ must be at10...30 V.The receiver output must

switch each time when avoltage of 10...30 V DC(Test+) or 0 V (Test–) ispresent on the test input.Contamination or mal-adjustment on the opticalaxis causes the emittersignal to reach the receiveronly weakly, if at all.Therefore the output will not

switch even though the testinput is activated. The testfunction provides a remotecheck of the thru-beam typeand serves as a preventivemeasure.

The test input ...(for series BOS 15, BOS 25,BOS 36, BOS 65, BOS 74)

... is a measure of thelights transmission ability ofa medium.

Transmission ... It is defined as the ratio of:– passed to– entering light (in %).

Diffuse transmission is theterm which is used when thelight is partially or completelydiffused.

In triangulation ... ... the light cones of athrough-beam systemintersect each other at anarrow angle. A target objectwill only be registered inthe area where the conesoverlap. The emitter lightwhich is reflected or diffusedfrom objects outside thislimited zone cannot be

registered by the photo-receiver. This fact canbe used to advantage inthe triangulation methodto sense relatively smalldistance changes(e.g. grooves, shaftrecesses). Color and shapeof the object have very littleeffect on the registration.

Rated switching distance sn

Actual switching distance (in % of sn)

Switching hysteresis (in %)

∅ of the response beam at sn/2 typ. (mm)

∅ of the active area (mm)

Diffuse

100 mm 200 mm 400 mm 1 m 2 m

125 125 125 135 150

≤ 20 ≤ 20 ≤ 25 ≤ 15 ≤ 15

20 25 150 300 300

Background suppression

120 mm 250 mm 1.1 m

135 135 135

≤ 1 ≤ 1 ≤ 1

6 10 25

Retroreflective

2 m 4 m 8 m

150 150 150

≤ 10 ≤ 10 ≤ 10

50 100 150

Through-beam

5 m 8 m 16 m 50 m

150 150 150 150

≤ 15 ≤ 15 ≤ 15 ≤ 15

8 12 12 20

Technical Data, general

Ambient operatingtemperature ...

... is the temperaturerange within which reliableoperation of the opto

switch is guaranteed.Balluff standard:–15 °C ≤ Ta ≤ +55 °C

Polarity reversalprotection

The supply voltage leadscan be reversed withoutdestroying the sensor. Incombination with the short

circuit protection, thesesensors are completelyprotected against miswiring.

Contamination ...(influence on the sensingrange)

... reduces the indicatedsensing range of sensorsand fiber optics ascompared with "pure air",because the dirt and dustparticles:

– accumulate on the lensesand affect theirtransparency, and

– absorb and diffuse thelight in the incoming beam.

An oil-free source of com-pressed air can be used toprevent dirt and contami-nation effects due to impureair.

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Emitter

Receiver

Target

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... illuminates in the "safe"range, where the inputenergy is at least 30 % overor under the "thresholdenergy".The "threshold energy"at which a signal changeis effected, is defined as100 %. The "safe" range istherefore reached when:

– the input signal is at130 % or more of thethreshold energy

– the input signal is at70 % or less than thethreshold energy.

Output(red LED)

Dar

k-on

Ligh

t-on

stable

unstable

stable

Switchingthreshold

Stability(green LED)

The contaminationindicator (green) ...(for series BOS 15, BOS 18(some), BOS 25, BOS 44,BOS 65, BOS 74)

Contamination scale Pure airTrace contaminationSlight contaminationModerate contamination

High contamination

Worst contamination

Ideal conditionsRelatively clean air in indoor roomsTool and storage roomsDusty and vaporous environmentswitching distance reduced by a factor of s = 0.5 su

Heavy precipitations, swirling flakes and chipsoptosensor function may failCoal dust precipitating on the lensoptosensor function may fail


2.0.22

Resistanceto mechanical impactper EN 60068-2-27

Pulse shape: half-sinePeak acceleration:300 – (30 gn)Pulse duration: 11 ms

m s2

3 shocks per main axisand direction, for a total of18 shocks

to continuous shockper EN 60068-2-29

Pulse shape: half-sinePeak acceleration:1000 – (100 gn)Pulse duration: 2 ms

m s2

4000 shocks per main axisand direction, i. e. 24.000shocks in total

to mechanical vibrationper EN 600068-2-6

Frequency range:10...2000 HzAmplitude: 1 mm(peak-to-peak) to 122 Hz30 gn above 122 Hz

Duration: 20 for eachposition and direction


photoelectric sensors principles - mehatronik sistem€¦ · sensors with background suppression...

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