Sensor Basics – Technology and Application · HRT: Reflection Scanner with background suppression VRT: Reflection Scanner with Foreground suppression. Diffuse Reflection. Like retro-reflective

Alex FerrellLeuze electronic

Sensor Concepts – Technology and Application

Alex FerrellProduct Marketing Manager

RK/PRK

RT/HRT

120m

12m

26m

LSThroughbeam principle

Reflection principle

Scanning principle

Function Principles

Leuze electronic | Sensor Technology | Alex Ferrell | 10/2015

Transmitter LSS… Receiver LSE…

A light beam sent from the transmitter is detected by the receiver.

Throughbeam Overview


Advantages of Throughbeam Sensors

• Very large operation range

• Very high performance reserve (in usage of short distances)

• Detection of very small objects using blinds (diaphragms) or laser source

• Reliable detection of shiny objects

• High price (high material and installation effort due to separate transmitter and

receiver)

• Double mounting, adjustment and cabling effort

Disadvantages of Throughbeam Sensors

Throughbeam – Advantages/Disadvantages


Large distances Outdoor Dirty environment Difficult / shiny objects

Throughbeam – Features/Applications


Sensor Reflector

RK: Reflecting head

Transmitter and receiver are located in the same housing. The light beam leaving the transmitter is reflected back by a reflector positioned opposite and detected by the receiver. The light must travel twice the distance, which results in lower operating ranges than the throughbeam principle.

Retroreflective – Operating Principle (RK/PRK)


Advantages of reflecting sensors• Reduced mounting effort (1x cabling, installation, adjustment)

• Reduced space ( flat reflector)

• Good reflector selection (for various situations)

• Cheaper than throughbeam sensor systems

• Reduced operating range compared to throughbeam systems

• Unwanted signals from reflecting objects possible

Disadvantages of reflecting sensors

Retroreflective – Advantages/Disadvantages


Reflecting PrincipleExample


RT: Reflection ScannerRTF: Reflection Scanner with fadingHRT: Reflection Scanner with background suppressionVRT: Reflection Scanner with Foreground suppression

Diffuse Reflection

Like retro-reflective photoelectric sensors, the transmitter and receiver are contained in a single device. However the transmitter light is not reflected by a reflector but by the object to be detected. In this case relatively little light gets back to the receiver which means shorter operating ranges - in the scanner this is referred to as scanning ranges - can be realized than with the reflection principle.

Transmitter and receiver unit Object

Scanning – Operating Principle


Scanning PrincipleIn which situations?

Function: Detection if something is in the light beam,but without access to the opposite side!


- distance of the object

- color of the object

- object size

- surface structure of the object

- pitch of the object surface

Scanning – Range Factors


A key parameter in scanners is the black/whitebehavior.

This refers to the relationship of the scanning ranges to black and white objects (b:a).

Scanning range (mm)

White 90%

Grey 18%

Black 6%Reduction of the scanning range (mm)

Scanning – Black/White Factor


Light coming from the transmitter hits the object, a part of it is reflected. A certain amount of this reflected light is collected by the receiver and causes a signal. If this signal is higher than the threshold set by teach button or potentiometer, the sensor switches.

Transmitter

Receiver

transmitter

receivertransmitter

receiver

Energetic Scanning – Operating Principle (ET/RT)


Diffuse Energetic Scanners RTTypical Applications

• Detection of objects of the same color and surface structure on conveyor tracks

• Simple collision protection on overhead conveyors

• Differentiation of strong contrasts• Plate glass detection (with no background

present)

Product examples:

RT 318

RT 46B

1000 mm scanning range limit


http://www.youtube.com/watch?v=Wu86DWw2Bg0&list=PLF9B1DC91A373AD13 Uhlmann Blister


http://www.youtube.com/watch?v=Wu86DWw2Bg0&list=PLF9B1DC91A373AD13

Case study: What happens if a dark object is to be detected against a light background?

Solution:... Option 1: Scanner with fading RTF, if the background is in a defined distance to the object... Option 2: Scanner with background suppression HRT

Diffuse Energetic Scanning – Background Effects


The field of view of the fading scanner is limited as the receiver unit is tilted. This scanner is “shortsighted”, the detecting range is smaller than the range of an energetic scanner. Objects which are outside the field of view are not detected, so signal from the background is faded out.

This object can bedetected.

This object cannot be detected.

transmitter

receiver

Fading Scanner – Operating Principle (FT)


Diffuse Energetic Scanners with Fading Typical Applications

• Object detection on conveyor tracks with- defined background- short scanning range

• Price-sensitive applications

RTF 25B

RTF 3B5 - 350 mm scanning range limit

10 - 550 mm scanning range limit

Product example:


Receivertransmitter

Near field receiver

Far field receiver

Background suppression scanners have two receiving elements arranged next to each other. Light reflected from the object near to the scanner hits the near field receiver, light from the background hits the far field receiver. By moving the double receiver element one can define the areas for near field and far field. The scanner will switch if the signal on the near field receiver is bigger than the signal on the far field receiver. This means a dark object in front of a light background is still detected if the sensor is set correctly.

Scanner w/ Background Suppression –Operating Principle


Scanner with Background Suppression Typical Applications

• Positioning tasksUniversally deployable in tight installation spaces where suppression is required for surrounding machine contours (e.g. special machine, construction, mounting/manipulation technology,...)

• Detection of- small objects- colored structured objects against a background

Product examples:

HRT 318

HRTR 46B-Teach2500 mm scanning range limit


HRTL 3B500 mm scanning range limit


Advantages of scanning sensors• Reduced mounting effort (1x cabling, installation, adjustment)

• No reflector required

• Cheaper than throughbeam sensor systems

• Reduced operating range compared to throughbeam and reflector systems

• Unwanted signals from reflecting objects possible

• More expensive than reflective sensors

Disadvantages of scanning sensors

Scanner – Advantages/Disadvantages


Forked SensorsGK 14 GS 04GSU 14DGSU 06GS 61

SR 53

Cubical Series SR 3B SR 25BSR 55 SR 8SR 18B SR 96SR 46B

SR 412 SR 318 SR 618

CylindricsM12, M18

FiberAmplifier LV463

SR 2

GS 63B

SR 318B

SR 28SR 5 SR 46CVarOS

Binary Switching Optical Sensor Lineup

SR 49C


Ultrasonic SensorsPhysical Basics

Ultrasonic sensors emit short, high-frequency sound pulses at regular intervals. These propagate in the air at the speed of sound. If they strike an object, they are reflected back to the sensor as an echo. The ultrasonic sensor internally computes the distance to the object based on the time which lapses between the emission of the sound signal and the reception of the echo. (Measures travelling time)

Applications: At edge of using optical sensors(glass detection, transparent objects, filling level, at optically difficult labels

LSSU (Transmitter)

LSEU (Receiver)

RKU (Reflex)

HRTU (Scanner)

VRTU (Scanner)


Wood

Bulk goods Glass

Packaging-materials

Highly polished surfaces

Metal

Liquids

Ultrasonic SensorsTypical objects and materials


http://www.euroquarz.de/uploads/pics/Faerbung_Schuettgueter_2.jpg

http://www.euroquarz.de/uploads/pics/Faerbung_Schuettgueter_2.jpg

http://de.flash-screen.com/free-wallpaper/fl-ssiges-wasser-der-erstaunlichen/erstaunliche-wasser-tapete-12810,1280x960,12810.jpg

http://de.flash-screen.com/free-wallpaper/fl-ssiges-wasser-der-erstaunlichen/erstaunliche-wasser-tapete-12810,1280x960,12810.jpg

Ultrasonic SensorsTypical Applications

Bottling Industry:bottle detection

(LSU 18)

Stretched Object Detection:

foil detection(HRTU 418)


Inductive SwitchesSensor Principal

Inductive proximity sensors detect the reduction of magnitude in the internal oscillating circuit.When an electrically conductible material enters the electromagnetic field, parasite Foucault currents are generated in this target object.These currents are consuming energy out of the sensor's oscillating circuit, whose amplitude will drop under the predefined trigger level.


Inductive SwitchesReduction Factors

Reduction factors are material dependent factors, which reduce the switching distance Srfrom the „norm“ distance

Sr = factor * Sn


Inductive SwitchesTypical Applications

End position detection

Switching cam


Contrast / Color / Luminescence Scanners Examples


Contrast / Color / Luminescence Scanners Difference

Color

One marking (color, grey level) on a (colored) constant reference

KRT

colorOne color or one markingon a multicolor reference

CRT

Luminescence

Luminescent marking

LRT


Contrast Scanner KRT

To detect One marking (color) on a single color or transparent reference


Color Scanner

One single color mark on an multicolor reference

Detection / control of the right color


Color Scanner CRTPrinciple

Multicolor

Transmitter (RGB)sequential emitting of colored light pulses

Receiverdiscrete sampling color selective (RGB) intensity / energy measurement

uP • Analysis of each measurement and translate into spectral values color

• Switching decision

t

t


Luminescence Scanner LRTPrinciple

UV

Transmitter

Receiverenergetic

uP • Teach values( Switching)

• Selection of light source with M-version

Black-Light effect


Measuring SensorsWhat are they used for?

How far?

How high?

How big?


Measuring SensorsDistance Sensors

Measuring distance: to an object / reference

Parameter:Range max. distance to measureResolution smallest detectable differenceAbsolute / relative accuracy max. deviation to realityMeasuring time / reaction time period until a value / first value is sent out


dz

Measuring Sensors Triangulation (far field)

Transmitter

CCD-line

Triangulation

Calculation in sensor:

Distance d = f(x)


Measuring Sensors Triangulation (near field)

dz

Transmitter

CCD-line

Best Accuracy in near range

Fast

Triangulation


Distance d = f(x)


Object

Measuring Sensors Time of Flight (TOF)

0:0000 ns:ps2:0855 ns:ps

Transmitter

Receiver

Distance d

t=0


Distance d = f(t)

Robust (i.e. ambient light) Accuracy in long range

TOF (Time of Flight)


Object

ODSL 30

ϕ

Measuring Sensors Phase Measurement

Distance d

Best Accuracy (in far range)


Distance d = f(φ)

P h a s e

Transmitting signal

Receiving signal with shifted phase (ϕ )


Triangulation: Depending on the absolute resolution of the CCD Accuracy linear to measurement distance in %

Phase / TOF: Depending on the time accuracy in the sensor constant accuracy in mm (independent on distance)

Measuring Sensors Sensor Selection

distance [z]

Resolution [dz]

1.5m

Phase shift ODSL 30

Triangulation1mm

3 mm

ODSL 96B TOFTime of flight

2m1m


ODS 96(B)ODSL 96

LED

Measuring Sensors 1D Measuring Sensors

ODSL 9ODSL 8 ODSL 30 AMS 300

Max. range 0,5 m 0,65 m 6 m 2,3 m 25 m 65 m 300 m

HRTU 418VRTU 430

Interface Analog U / A,

2x switch

Analog U / A, RS232, RS485,

2x switch,(MA 2xxi)

Analog U / A,

1x switch


2x switch,(MA 2xxi)


3x switch,(MA 2xxi)

RS232, RS422, RS485,field-busses!!!!

Accuracy ± 2mm ± 2 .. 5mm± 0,4 .. 20mm ± 0,25 .. 6,5mm ± 7,5 .. 90mm ± 1,5..69mm ± 30mm

Meas. time 30 .. 100ms 1,6ms2 .. 7ms 2ms 100 .. 400ms 1 .. 7ms 1,4 ..100ms

Triangulation P h a s eTOFTriang.Triangulation P h a s eTOF


Function in details:

FIB : First interrupted beam

LIB : Last interrupted beam

FNIB : First not interrupted beam

LNIB : Last not interrupted beam

TIB : Total interrupted beam

TNIB : Total not interrupted beam

Measuring Sensors CML700i Measuring Light Curtains


Measuring Sensors CML700i Applications


Measuring light curtainsCML700i series – typical applications


Measuring light curtainsCML700i series – typical applications


The important features Operating range up to 6m

Solutions for a lot of industry applications Fastest cycle time

For detection in fast processes Display

Full parametrization und visualisation Connector at rearside

Minimal deazoneMeasuring field height until 3000mm

Measurement of large objects Excellent resolution

Detection of minimal change of dimension

Measuring light curtainsCML700i series


The characteristics:

Analog output (Current-or voltage range configurable)

IO-Link interface (the general interface for CML)

Integrated fieldbus connection (CANopen, Profibus in preparation)

Ethernet-fieldbus connection via IO-Link-master modul

Up to 4 in- / outputs (configurable)

Teach- and/or trigger input

Digital Area-Outputs, warn out (autoControl), trigger out

Display (alignment / configuration / statusinformation)

Connector axial or rear side (still everything under control)

Measuring light curtainsCML700i series


Measuring Sensors Application Diameter and Position

Detection of up to 3 objects with a diameter of > 0,5mm

Resolution 14µm (mode 7)

Measuring mode 7 (max. measuring frequency 50Hz): Serial output of every edge position (binary)

Measuring mode 1-5: Resolution of 0,1mm

Digital data output via RS232 or RS422


Measuring Sensors Edge Detection and Position Control

Detection of edges e.g. paper, metal, wood (no transparent objects)

Teaching to reference position (→ 5V / 10mA)

Analog edge output ( 0-10V / 4-12mA )


Range: 0 – 65 mAngle: 190°Angular resolution: 0,36°Scan rate: 25 Hz

• Interface: Fast Ethernet, configuration interface

• Data block: x,y, distance (per scan)

• Integrated, online data analysis: (x,y coordinates, extreme value analysis)

Measuring Sensors –Optical Surface Distance Sensors


Measuring SensorsLine Profile Sensor

z

x


LRS 36 (Line Range Sensor):

Detection

LPS 36(Line Profile Sensor):

2D/3D Analysis

LES 36(Line Edge Sensor):

Edge analysis

Measuring SensorsLine Profile Sensor Overview

Switching deviceInterface: I/O, PROFIBUSInternal data processing

Measuring deviceInterface: analog, PROFIBUSInternal data processing

Measuring deviceInterface: Ethernet, Encoder External data processing 1564 bytes data per scan


Measuring SensorsLine Profile Sensor

Switching / measuring: “Look into the box”

Switching: Conveyor control

Measuring: Object profile


Point to Point communication options

• Analog output (voltage, current)Advantages: Inexpensive, proven technology, universalDisadvantages: Input cards have varying number of bits resolution, have to scale the value, issues with scaling at both device level and input, susceptible to noise, only get data value

• Serial output (RS232, RS422, RS485)Advantages: Proven technology, universalDisadvantages: Have to set up input and device to match protocol, have to parse the data value into a useable format, susceptible to noise

• IO-LinkAdvantages: Digital data input, can get device status information, can access parametersDisadvantages: Need an IO-Link master


Measurement SensorsHow to get the data?


WHAT IS IO-LINK?IO-Link is a bi-directional point-to-point serial communication protocol used to

communicate with sensors and/or actuators

IEC 61131-9


5 THINGS TO KNOW ABOUT IO-LINK

1. Higher Level Flexibility:Easy to read, parameterize or configure smart devices without touching them.

2. Simple Device ReplacementSimple replacement of devices by being able to download parameters into the replacement right from the controller automatically. (Never redo work which you have already done!)

3. IO-Link is an Open Consortium of Manufacturers:New products are released on a regular basis and IO-Link is gaining ground in NorthAmerica as well as in Europe where it is already in widespread use.

4. Simple Serial Point to Point Communication:Uses a simple standardized cabling architecture.

5. Multiple Smart Devices per Address:A basic benefit of IO-Link is to allow for multiple smart network type devices tobe connected to one address and thus allowing for more devices to be connected inone network.


IO-LINK BENEFITSSimplified

installationAutomated

parameter settingExpanded

diagnostics

• Long-term cost reductions at all levels

• Standardized for easy operation

• Minimized downtimes through intelligent remote parameter management

• Comprehensive device diagnosis down to field level

• Enhanced flexibility in application

• Long-term investment security due to international standardization

Fieldbus communication optionsAdvantages: High speed, high bandwidth communications, can get data as well as status and parameter data, bi-directional communications

Disadvantages: Expensive, mainly PLC manufacturer dependent, more complicated to set up

• PROFIBUSNode-based industrial network primarily used with Siemens PLCs

• PROFINETIndustrial Ethernet network based on TCP/IP primarily used with Siemens PLCs

• Ethernet/IPIndustrial Ethernet network based on TCP/IP primarily used with Rockwell Automation (Allen-Bradley) PLCs

• Many Others such as DeviceNet, EtherCAT, Modbus, Modbus TCP…


Measurement SensorsHow to get the data?

Documents

Sensor Basics – Technology and Application · HRT: Reflection Scanner with background suppression VRT: Reflection Scanner with Foreground suppression. Diffuse Reflection. Like retro-reflective