Skan-A-Matic

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Technical Information

Discover the technology of photoelectric sensors. Learn about the components of a photoelectric system, the different sensing modes, how to choose a system and how to use the system. Also there is a helpful glossary for the beginner.

Thrubeam

Skan-A-Matic thrubeams deliver the most positive sensing signal. They consist of a separate light source and photodetector placed on opposite sides of objects to be detected. Detection occurs when the beam of light between them is broken by the object.

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Reflective Sensors

Skan-A-Matic reflective scanners combine a light source and photodetector within a single housing. Light is emitted by the source and returned to the photodetector - either by reflecting off a target or a special retroreflective surface.

Special Purpose Sensors

Skan-A-Matic special purpose sensors are custom designed for those unique applications not covered by our standard line-up. We offer skanners to detect liquid levels, colors and wafers for the semiconductor industry. Some of our special purpose sensors are furnished with flexible fiber optic probes to detect objects in inaccessible places. If you have a special need, Skan-A-Matic can design the unit to meet your requirements.

Self-Contained Photoelectric Controls

Skan-A-Matic self-contained photoelectric controls combine sensor and control in one package. This results in less installation time, and lower cost for each sensing position. These sensors also have superior immunity to electrical noise than a separate sensor and control combination.

Controls

Skan-A-Matic controls allow designers the option of altering the function of photoelectric scanners to suit the requirements of each individual application. Our photoelectric controls offer on/off time delay, and other logic circuitry for single and multiple scanner operations. Our modular approach allows you to assemble a specific photoelectric system customized to your particular applications.

Accessories

Reflective tape, retroreflective disks, connectors and miscellaneous technical information.

 
Technical Information
Components of a Photoelectric System
Light Sources 6
Lamps 6
LED's 6
Photodetectors 7
Optical Filters 7
Colors 7
Controls 8
Response Time 9
Output Devices 9
Open Collector Transistor 9
Relay 110
Solid-State Relay 11
Modulating Controls 12
Sensing ModesThrubeam 13
Retroreflective 13
Diffuse Reflective 14
Specular Reflective 14
Technical Specifications 14
Quality Control 16
Performance Guarantee 16
Choosing a SystemThrubeam or Skanner? 16
Choosing a Thrubeam17Thrubeam Example 17
Choosing a Reflective Skanner 18
Reflective Skanner Example 18
Choosing a Control 19
Using Photoelectric ProductsWiring 20
Grounding, Shielding & Noise 21
Logic Operations 21
The Environment 22
Temperature Effects 22
Sensitivity Adjustment of Controls 23
Using a Remote Potentiometer 23
Sensitivity Adjustment Procedure 24
Glossary 25-26
 

Thrubeams

Thrubeams, or thrubeam pairs, are photoelectric sensing devices packaged in two separate housings. One part, the light source, produces light and projects it as a narrow beam. The other half of the pair, the photodetector, is positioned some distance away facing the light source so it can sense the emitted light.

When the space between light source and photodetector is clear, the photodetector is brightly illuminated and electric current flows in the photodetector circuit. A target is detected when an opaque object blocks the beam path - the photodetector is darkened and conducts less current. An amplifying control monitors the flow of current in the photodetector circuit and turns a switch on or off when necessary. Because of this high contrast between light and dark states, a thrubeam provides highly reliable indication that a target is present.

Thrubeam Selection Guide
 
SeriesRated SeparationBeam DiameterSmallest Detectable ObjectLight SourceInput Current (mA) Continuous/ModulatedBodyMountingCatalog Pages
 
L43/P43 Super Thrubeam 100' .40" .15" IR LED 100/100 Aluminum 3/4 - 16 THD 28-29
L33/P33 36" .16" .05" IR LED Vis Red LED 100/100 50/80 Aluminum Stainless Steel 3/8-24 THD 5/16-24 THD 30-31
L30/P30 3" - 24" .06" - .12" .02" - .04" Lamp IR LED 115 100/1000 or 40/80 Aluminum, Brass, Stainless Steel Various 32-37
L34/P34 6" .06" .02" IR LED 60/120 Stainless Steel 8-32 THD 38-39
L11/P11 2" .10" .04" IR LED 40/80 Plastic ---------- 40
L56/P56 .50" .030" .010" Lamp IR LED 115 100/1000 Aluminum / Plastic Composite .113" holes 41-42
L60/P60 36" .06" .02" IRED/LED 60/120 mA 40/80 mA Plastic .086" holes

43-44

 

Reflective Sensors

Reflective scanners use the same physical principles as thrubeams except that the two components - light source and photodetector - are placed together in the same housing. Light is projected into space by the source. The target object reflects some of this light, and a portion of it enters the photodetector, causing increased current flow in the photodetector circuit. Since most of the light emitted by the light source is lost, only a small percentage is collected by the photodetector.

Reflective skanners do not have the range capabilities of thrubeams, since their light/dark contrast ratio is not as great. However, they do have advantages over thrubeams in many situations. First, they need only be located on one side of the target object - this means that only once wiring is needed and that there will be no problems aligning the two separate components. Second, reflective skanners can some times detect clear, thin films such as cellophane which cannot be detected by thrubeams. Third, reflective skanners can often distinguish targets by surface characteristics such as texture and color.

Reflective Sensor Selection Guide
 
SeriesSmallest Detectable ObjectOptimum Distance to TargetField of ViewMaximum Usable DistancesLight SourceInput Current (mA) Contin./Mod.BodyMountingCatalog Pages
 
S22 Retro-Skan .15" N/A N/A 30" (with 3" retro-Disc) IR LED 100/100 Aluminum 1/2-20 THD .180" holes 46-47
S12 Squint-Skan .12" .18" .35" 1.5" IR LED 100/100 Aluminum .125" holes 48-49
S111 Plasti-Skan .06" .15" .18" 1.3" IR LED 40/80 Plastic .089" holes 50-51
S13 .04" .30" .11" 1.5" IR LED 60/120 Aluminum 3/8-24 THD .089" holes 52-53
S30 Skan-Coax .04" .10" .10" .6" - 1.0"
Lamp
IR LED
Vis Red LED
115
100/1000
50/80
Aluminum Various 54-56
S14/S15/S16 .04" - .05" .07" - .16" .10" - .15" .4" - 3.0" Lamp 115 Aluminum, Brass 3/8-24 THD .089" holes 57-59
S27 Micro-Skan .01" .02" .04" .20" IR LED 60/120 Gold Plated TO 18 can --------- 60-62
S51/S52 Mini-Skan .011" .030" .033" .100"
Lamp
IR LED
Vis Red LED
115
100/1000
50/80
Aluminum/ Brass 5/16 THD .089" holes 63-65
S56 Nano-Skan .007" .010" .020" .070"
Lamp
IR LED
Vis Red LED
115
100/1000
50/80
Aluminum/ Plastic Composite .113" holes 66-68
S56 High Speed Nano-Skan .007" .010" .020" .070"
Lamp
IR LED
115
100/1000
Aluminum/ Plastic Composite .114" holes 69-70
S58 Pico-Skan .004" .006" .012" .020" Lamp 115 Aluminum/ Plastic Composite .113" holes 71-72

 

Special Purpose Sensors

Special Purpose Sensors are designed for unusual situations where nothing else will do the job. These sensors are often of limited usefulness for applications other than the original design application. The S19 Sight Glass Skanner, for example, has only one known application - detecting the liquid column in a transparent sight glass tube.

The S28 Wafer-Scan was originally designed to detect silicon wafers for the semiconductor industry but can be used for many short range applications. The S35 can be used to detect a predetermined color against a contrasting background. The S17, with its detachable fiber optic cables, can be used when scanning must be done in a hostile environment. The heat and chemical-resistant cables can be exposed to harsh conditions while the skanner body remains at a safe distance.

Special Purpose Sensor Selection Guide
 
SeriesOptimum Distance to TargetField of ViewLight SourceInput Current (mA) Contin./Mod.BodyMountingCatalog Pages
 
S35 Color Detection Skanner .10" .10" Lamp 115 Aluminum 5/16-24 THD .113" holes 74-75
S28 Wafer-Skan .05" N/A LED 40/80 Aluminum .093" holes 76-77
S19 Sight Glass Skanner N/A N/A Lamp 115 Aluminum ---------- 78-79
S17/L17/P17 Enviro-Skan See Description See Description
Lamp
LED
115
100/1000
Aluminum Various

80-82

 

Self-Contained Photoelectric Controls

Self-Contained Photoelectric Controls combine the function of a reflective skanner and a DC powered control in one package. This has several advantages for the user. Hookup is simplified by having one device to wire up rather than two. Interference by electrical noise generated in industrial environments is minimized by reducing the distance from the sensor to the control to zero. Most units are directly compatible with a programmable controllers, and can be connected with just a three or four wire hookup. A Self-Contained Photoelectric Control has a lower purchase price than a separate skanner and control thus reducing inventory cost.

Self-Contained Photoelectric Controls Selection Guide
 
SeriesSmallest Detectable ObjectOptimum Distance to TargetBeam DiameterField of ViewMaximum Usable DistanceLight SourcePower InputBodyCatalog Pages
 
C32 Skamp .04" .10" N/A .1" 3" Lamp
LED
5 VDC @ 185 mA or 8-25 VDC @ 60 mA Aluminum 84-85
C40000 Reflective Square Skamp .010" 1" ± .15" N/A .03" N/A visible red LED 5 or 8-28 VDC @ 100 mA die-cast zinc 86-88
.030" 2" ± .75" N/A .1" N/A
C40000 Retroreflective Square Skamp 1" N/A 3" N/A 10' (with 3" retro-disc) visible red LED 5 or 8-28 VDC @ 100 mA die-cast zinc 86-88
C56 Nano-Skamp .007" .010" N/A .020" .070" Lamp
LED
5 VDC @ 185 mA or 8-25 VDC @ 60 mA Aluminum 89-90

 

Controls

Controls produce the useful output in photoelectric systems. A control has two main functions - it must amplify the very small current flowing in the photodetector circuit, and it must perform some sort of switching action to let outside equipment know that a target has been detected. Controls will usually have secondary functions, including: power supply, sensitivity control, visible indication of the state of the output, and logic and time delay functions.

Skan-A-Matic photoelectric devices are designed to be used as interchangeable modules. Individual pieces work together as a complete system. Most controls will operate any skanner or thrubeam. This means you have the freedom of choosing a control and mating it with any skanner to achieve optimum sensing performance.

Controls Selection Guide
 
SeriesInputSwitched OutputResponse TimeEnclosureMountingCatalog Pages
 
T21004 5 VDC @ 2 mA 40 VDC @ 40 mA * 1" square plastic module Printed Circuit Board 94
T21104 5 VDC @ 20 mA 40 VDC @ 100 mA * 1" square plastic module Printed Circuit Board 95
T21028 5 VDC @ 110 mA 28 VDC @ 100 mA 5 ms 1x2" plastic module Printed Circuit Board 96
T31 / T32 5 & 8-28 VDC @ 28 mA 25 VDC @ 250 mA * Plastic can, plastic module 8 pin socket, flat mount 97-98
T325 5 VDC @ 125 mA 30 VDC @ 100 mA 5 ms plastic module Flat mount 99-100
T36 5, 12, 24 VDC @ 18 mA Input VDC @ 100 mA * plastic can 8 pin socket 101-102
R40 / T40 115 VAC @ 2 VA 115 VAC @ 5 A, SPDT 25 VDC @ 100 mA 25 ms * plastic can 11 pin socket 103-104
T41300 115 VAC @ 2 VA 25 VDC @ 100 mA * plastic can 11 pin socket 105-106
R42 / T42 115 VAC @ 2 VA 115 VAC @ 5 A, SPDT 25 VDC @ 100 mA 25 ms 5ms plastic can 11 pin socket 107-108
R43 / T43 Super Pulser ** 115 VAC @ 4 VA 115 VAC @ 5 A, SPDT 25 VDC @ 100 mA 25 ms 1 ms plastic can 12 pin socket 109-111
T44000 115 VAC @ 2 VA 250 mA open collector 20 ms plastic can 11 pin socket 112-113
R46 / T46 115 VAC @ 2 VA 115 VAC @ 5 A, SPDT 25 VDC @ 100 mA 25 ms * plastic can 11 pin socket 114-116
R47 / R48 115 VAC @ 2 VA 5 A, 10 A relay 2.0 A solid state relay 250 mA open collector 25 ms with relay 9 ms with solid state relay Nema 12 steel box Wall mount 117-119
R60 115 VAC @ 10 VA 5 A, 10 A relay 2.5 triac 250 mA open collector 25 ms with relay 9 ms with solid state relay Nema 12 steel box Wall mount 120-124
T60 5 VDC or 8-28 VDC @ 175 mA Open-Collector NPN and PNP rated at 100 mA 5 ms Plastic module NS32 or NS35 DIN Rail 125-126

 

Accessories

Accessories in Skan-A-Matic Catalog

  • Retroreflective Tape
  • Retroreflective Discs
  • Photoelectric Control Sockets
  • Cable Connectors

 

Catalog Page: 127