2. C O M P A N Y ISF-101 Industrial Sensor Fundamentals Instructor Rob Smith

3. C O M P A N Y

4. Objectives of ST120 With the fast paced industrial world looking for ways to manufacture products better, faster and more economically, it is important to be knowledgeable of sensor technologies.

5. C O M P A N Y Continued This class is designed to give you a fundamental understanding and working knowledge of different sensor technologies. We will achieve this through the study of sensor technologies, terminology explanations, lab exercises and application examples.

6. C O M P A N Y What Is a Sensor According to Merriam-Webster's dictionary, it’s a device that responds to a physical stimulus and transmits a resulting impulse.

7. C O M P A N Y Advantages of Electronic Sensors Non-contacting Wear and tear is kept to a minimum A must for fragile equipment Odd shapes (not a problem) Reliable Last a long time (Solid State) A mechanical switch has a definite life span Few maintenance problems Longer/better reliability

8. C O M P A N Y Continued Variety of sensing Capabilities Speed Almost any size sensor Almost any size object (* getting smaller) Variety of Design Features Quick disconnect Short circuit protection Diagnostic features (alarm output, check input, indicator lights)

9. C O M P A N Y Types of Sensors Photoelectric Through-Beam Retro-Reflective Diffuse Reflective Fiber Optics Color Mark Specialized Proximity Inductive Capacitive Miscellaneous Ultrasonic Reed Variable Reluctance Laser Specialty Sensors

10. C O M P A N Y TYPES OF SENSORS Inductive Proximity Capacitive Proximity Photoelectric

11. C O M P A N Y Chapter 1 Proximity Sensors

12. C O M P A N Y Proximity Sensors Variations –Inductive –Capacitive

13. C O M P A N Y Inductive Proximity Sensor Counting teeth in gears

14. C O M P A N Y Basic Construction and Circuit Make-up. 1. Sensor Head 2. Oscillator Circuit 3. Detector Circuit 4. Switching Circuit (output) DETECTOR OUTPUT SENSOR TARGET OSCILLATOR OPERATING PRINCIPLE Inductive Proximity Sensor

15. C O M P A N Y 1. Sensor Head DETECTOR OUTPUT SENSOR TARGET OSCILLATOR OPERATING PRINCIPLE Inductive Proximity Sensor The front end of the sensor consists of a wire-wound ferrite iron core. This is the physical part of the sensor that produces the actual sensing field.

16. C O M P A N Y Metal Object Primary Magnetic Field Eddy Current Oscillator Detecting Circuit Detecting Circuit Sensor The Sensing Field

17. C O M P A N Y 2. Oscillator Circuit DETECTOR OUTPUT SENSOR TARGET OSCILLATOR OPERATING PRINCIPLE Inductive Proximity Sensor The oscillator is the circuit that powers the wire winding in the core and its “power” is monitored by the detector circuit for resulting detection.

18. C O M P A N Y Sensing a Moving Target On Off On Moving Object Amplitude of oscillation Off

19. C O M P A N Y 3. Detector Circuit DETECTOR OUTPUT SENSOR TARGET OSCILLATOR OPERATING PRINCIPLE Inductive Proximity Sensor The Detector Circuit converts the amplitude of the oscillating signal to a DC RMS level from which the ON and OFF thresholds are used to trigger the output circuit.

20. C O M P A N Y Sensor Turn-On/Turn-Off Process Observed Voltage Level in the Detection Circuit Output switching thresholds ON Off ON Off Hysterises

21. C O M P A N Y 4. Switching Circuit (Output) DETECTOR OUTPUT SENSOR TARGET OSCILLATOR OPERATING PRINCIPLE Inductive Proximity Sensor The Output Circuit handles the actual switching and control of the output.

22. C O M P A N Y Sensing Distance Sensing Zone Sensing Distance The Sensing Zone

23. C O M P A N Y Shielded and Unshielded “Shielded” and “Unshielded” are two terms used to describe these sensors. The basic difference in these two types arrive from their mechanical construction.

24. C O M P A N Y Shielded and Unshielded The ferrite core/winding construction varies between the two styles, as does the shielding. Cores Shielding

25. C O M P A N Y Shielded and Unshielded In general, these two construction styles yield slightly different sensing performances. In summary, the unshielded style will provide approximately twice the sensing distances with an inherent drawback of specific mounting and installations requirements.

26. C O M P A N Y Sensing Distance Shielded 18mm 30mm dia. Un-Shielded 10mm 30mm dia.

27. C O M P A N Y Target Consideration 1. Target Characteristics Composition Size and Thickness Shape 2. Speed of Target 3. Target spacing or interval 4. Frequency Response of the sensor

28. C O M P A N Y Choosing the right Inductive Sensor Bad Target too small for sensor Good Target and sensor size comparable

29. C O M P A N Y

30. Sensing Metal Lid on Containers

31. C O M P A N Y Sensor Wiring

32. C O M P A N Y

34. Inductive Proximity Sensor – Lab Exercise Hook up the sensor and verify its operation by sensing the Din rail on your demo board. (The control relay should activate when the output turns on). Lay the sensor on it’s side, directly on the din rail. Does the output activate? _______ Why?_______________________________________

35. C O M P A N Y Continued Test the sensitivity of the various metal objects: 1.Using the paper from your note pad. Place one piece of paper on the test units. Press the sensor nose down on the paper. 2.Continue adding paper until the sensor no longer senses the test object. 3.Record the number of sheets, before detection was lost.

36. C O M P A N Y Continued Recordings 1.Steel Bolt_____ 2.Aluminum_____ 3.Copper (penny)_____ 4.Brass Fitting_____ Bonus: Can non-metallic objects be sensed? _____

37. C O M P A N Y Specifications – Catalog Review E2A 3-Wire DC Series P. F-44

38. C O M P A N Y Capacitive Proximity Sensors

39. C O M P A N Y A Capacitive Proximity sensor is similar to an inductive sensor in that it has a Oscillator, Detector and Output circuit. It differs in that it uses a plate shaped Electrode instead of a wire-wound core. In operation, it forms an electrostatic capacitive field formed between it and the the sensors ground. (In practice the supply line is in effect the ground.) Sensing Circuit Electrode Plate SENSOR Oscillator Circuit Detector Circuit Output Circuit Ground

40. C O M P A N Y When there is no target object in the area of the sensor the field that is formed will be stable.

41. C O M P A N Y When a target object nears the sensor its positive and negative charges (normally neutralized) separate. The negative charges in the target are attracted towards the electrode, and its positive charges towards ground. This “influence” increases the electrostatic capacitance of the electrode which increases its coupling with ground. This provides increased amplitude in the oscillator circuit, which is in turn used to switch the output in the detection circuit.

42. C O M P A N Y Capacitive Sensing Range Affects sensor setting distance Objects Size & Shape

43. C O M P A N Y Dielectric Constants The measure, or unit of Dielectric Constant, is the ability of a material to concentrate electrical flux. Its numerical value is specified as the ratio of flux in the material verses the flux in air or vacuum. The dielectric constant of air or vacuum is 1 – since it is the reference.

44. C O M P A N Y MaterialsConstants Acetone19.5 Acrylic Resin2.7-4.5 Air1.000264 Alcohol25.8 Ammonia15-25 Aniline6.9 Aqueous Solutions50-80 Bakelite3.6 Benzene2.3 Cable Sealing Compound2.5 Carbon Dioxide1.000985 Carbon Tetrachloride2.2 Celluloid3.0 Cement Powder4.0 Cereal3-5 Chlorine Liquid2.0 Ebonite2.7-2.9 Epoxy Resin2.5-6 Ethanol24 Ethylene Glycol38.7 Fired Ash1.5-1.7 Flour1.5-1.7 Freon R22 & 502 (liquid)6.11 Gasoline2.2 MaterialsConstants Glass3.7-10 Glycerin47 Hard Paper4.5 Marble8.0-8.5 Melamine Resin4.7-10.2 Mica5.7-6.7 Nitrobenzene36 Nylon4-5 Oil Saturated Paper4.0 Paraffin1.9-2.5 Paper1.6-2.6 Perspex3.2-3.5 Petroleum2.0-2.2 Phenol Resin4-12 Polyacetal3.6-3.7 Polyamide5.0 Polyester Resin2.8-8.1 Polyethylene2.3 Polypropylene2.0-2.3 Polystyrene3.0 Polyvinyl Chloride Resin2.8-3.1 Porcelain4.4-7 Powdered Milk3.5-4 Press Board2.5

45. C O M P A N Y MaterialsConstants Quartz Glass3.7 Rubber2.5-35 Salt6.0 Sand3-5 Shellac2.5-4.7 Shell Lime1.2 Silicon Varnish2.8-3.3 Soybean Oil2.9-3.5 Styrene Resin2.3-3.4 Sugar3.0 Sulpher3.4 Teflon2.0 Toluene2.3 Transformer Oil2.2 Turpentine Oil2.2 Urea Resin5-8 Vaseline2.2-2.9 Water80 Wood (dry)2-7 Wood (wet)10-30

46. C O M P A N Y Mutual Interference

47. C O M P A N Y

48. Application Sample High Water Limits Low Water Limits

49. C O M P A N Y Capacitive Proximity Sensor – Lab Exercise In this exercise we will be using the Capacitive Proximity style sensor in a very typical application use. To detect the fluid level of a liquid. Follow the outlined steps to complete the lab.

50. C O M P A N Y Materials needed: Sensor, power supply, plastic container and water Wire the sensor to the power supply, and apply power. Position the face against the plastic bottle at locations above the water line and adjust the sensitivity (potentiometer). The LED indicator will be on, back the adjustment off so that the indicator goes off.

51. C O M P A N Y Continued Move the sensor down along the side of the bottle to a location with fluid in front of the unit. At this point the LED will again turn on. Move the sensor up and down along the side, checking to see if the sensor activates at the water level. If not readjust until sensor works properly.

52. C O M P A N Y

53. Specifications – Catalog Review E2K-C Series P. F-130

54. C O M P A N Y Chapter 2 Photoelectric Sensors

55. C O M P A N Y Photoelectric Sensors

56. C O M P A N Y Photoelectric Sensors Variations –Through-beam –Retro-reflective –Diffuse reflective –Fiber optics –Color mark –Specialized

57. C O M P A N Y Through Beam Sensors Through Beam

58. C O M P A N Y Principle of Operation Through-beam sensors consist of two parts, an emitter (the light source) and a receiver (the detector). A beam of light links the two - establishing a sensing area. Receiver Emitter

59. C O M P A N Y Principle of Operation The target to be detected passes through the beam, breaking the link between the emitter and the receiver. When this occurs, the object has been sensed. Receiver Emitter

60. C O M P A N Y Amplifier Unit Output Circuit Light Detecting Circuit Light Emitting Element Principles of Operation Moving Object

61. C O M P A N Y Amplifier Unit Output Circuit Light Detecting Circuit Light Emitting Element Principles of Operation Moving Object

62. C O M P A N Y As the method of operation is by breaking the beam, the sensor is not affected by the target’s color, texture or glossiness. However, the size of the object must be taken into consideration. Some through-beam sensors have sensitivity adjustments to allow different sizes to be detected. Receiver Emitter

63. C O M P A N Y Mode of Operation Light On – The output of the sensor operates when the beam is uninterrupted. Receiver Emitter ON

64. C O M P A N Y Mode of Operation Dark On – The output of the sensor operates when the beam is interrupted. Receiver Emitter ON

65. C O M P A N Y Installation Sensing distance Alignment Mutual interference

66. C O M P A N Y Retroreflective

67. C O M P A N Y Principles of Operation Unlike the through-beam sensor, the retroreflective sensor has the emitter and receiver in one body. The light beam is established by the use of a reflector, returning the light from the transmitter back to the receiver.

68. C O M P A N Y Retro-Reflective

69. Like the through beam sensor, the object is detected by breaking the path of the beam. The retroreflective sensor has an advantage over the through beam type, in that the unit requires wiring of only one component.

70. C O M P A N Y Since the target is detected by breaking the beam, the operation is not affected by the object color or shape.

71. C O M P A N Y Just like the through beam, the sensor can operate in Light On and Dark On mode.

72. C O M P A N Y Possible Problems Even though color and shape do not affect this sensor type, the sheen or glossiness of the item may have an adverse affect. If the object is extremely shiny, or highly reflective, it could reflect more light back to the receiver than the reflector does on its own. It this case the object could/would pass by undetected. As a commonly found issue, there is a solution for these applications.

73. C O M P A N Y Polarized Retroreflective

74. C O M P A N Y Operation Instead of thinking of light as one uniform beam, simplified it can be split into two components that make up the beam. These components are horizontal and vertical light waves. Horizontal Vertical Beam

75. C O M P A N Y Polarized Retro-Reflective Sensor Horizontal Light Returned 90 0 Vertical Light Out 90 0 Reflector

76. C O M P A N Y Reflector Shiny Object Reflector Sensor

77. C O M P A N Y Polarized Retroreflective – Lab Exercise Materials needed: 1.Sensor and sensor controller.(E3S-AR81) 2.Plexiglas squares ¼” and ½” thick. 3.Orange reflector 4.Red and white reflector 5.Shinny aluminum

78. C O M P A N Y Hook up the sensor to the sensor controller. DO NOT CONNECT THE BLACK SIGNAL WIRE! This is a PNP sensor not compatible with the controller. Therefore, for this exercise we will be utilizing the indicators LED’s for diagnostics. Place the sensor in the clamp and set the sensitivity to its maximum. Have your lab partner hold the reflector and back it away until you find the maximum distance. What is the maximum stable distance? __________

79. C O M P A N Y Space the sensor and reflector approximately 5-8 inches apart and adjust the sensitivity so that a clear ½” thick piece of Plexiglas can be detected. Repeat process for the ¼” Plexiglas. Can this object type be detected with stable sensor operation? _______ Try detecting the following objects. MaterialSuccess Y / N Orange Reflector Red/White Reflector Shiny Aluminum Foil

80. C O M P A N Y Diffuse Reflective

81. C O M P A N Y The Diffuse sensor incorporates the Emitter and the Receiver in the same body, much like the Retro- reflective sensors.

82. C O M P A N Y Unlike the retroreflective sensor, there is no separate reflector in use to return light back to the receiver. Instead, this sensor type relies on light reflection coming off of the object itself. This configuration has the advantage one-piece wiring, and no reflector. This is especially useful in those applications where there may be access to only one side, or mounting problems exist.

83. C O M P A N Y Background Suppression In some applications the background behind the object being sensed can have adverse effects on the sensor's ability to detect the object.

84. C O M P A N Y Diffuse Reflective – Lab Exercise Hook up the sensor and verify its operation by placing your hand in front of the sensor to activate the output. Set the sensitivity of the sensor to its maximum setting. Position a piece of the colored paper in front of the sensor and slowly back it away to find the maximum sensing distance. Repeat this process for each test piece and document your results.

85. C O M P A N Y Recordings Color and SheenMaximum Distance (inches) White (Matte) White (Glossy) Green (Matte) Green (Glossy) Blue (Matte) Blue (Glossy) Black (Matte) Red (Matte) Red (Glossy)

86. C O M P A N Y Could this sensor be used to differentiate colors (COLOR MARK SENSOR) ?________ Why________________________________________ ____________________________________________ Try to detect the black foam material. Is it detectable?_______ Why________________________________________ ___________________________________________

87. C O M P A N Y For Your Information If all of these sensors work on the principal of light, then why does the ambient light affect the sensor?

88. C O M P A N Y Modulation Modulating an LED means turning it on and off at a set frequency. This is generally done at high frequency with short bursts of voltage. By applying power in this manor the circuit is able to generate a very high intensity light at a certain spectrum. Because the LED is not on continuously it does not suffer from the adverse affects of heat.

89. C O M P A N Y Continued The secret of a modulated system’s superior performance is that the sensors receiving circuit is tuned to the emitters specific light spectrum. Since the receiver is set to respond specifically to this spectrum, the effects of ambient light are virtually ignored. This is similar to a radio receiver which tunes solidly to one station, while ignoring all other radio waves that are present.

90. C O M P A N Y Comparison Chart 1 TargetThru-beamRetroreflectiveDiffuse Dark opaque Good Poor Shiny opaque GoodPoorGood Clear PoorGoodPoor Multi colored opaque GoodMaybePoor Light opaque GoodMaybePoor Translucent MaybeGoodMaybe

91. C O M P A N Y Comparison Chart 2 TargetThru-beamRetroreflectiveDiffuse Range (Feet) LongMediumShort Detection GoodFairFair/Poor Repeatability ExcellentFair Environmental Resist ExcellentFair Installation Cost HighMediumLow Adjustment Time Low Medium Versatility Medium Low

92. C O M P A N Y Specifications – Catalog Review E3Z Series P. B-122

93. C O M P A N Y Fiber Optics

94. C O M P A N Y Fiber optic photoelectric sensors consist of two parts, the amplifier and the sensing head. The amplifier contains the emitter (light source) and the receiver (detector) along with their associated electronics. The fiber optic cable is the means used to transfer the light to the sensing head.

95. C O M P A N Y Why Fiber Optics Allows for use of sensors in small areas (flexible). Can be used in Hazardous areas. Ability to see small objects (0.5mm or.002” diameter with addition of a lens). Can be used in high and low temperatures.

96. C O M P A N Y

97. Transmission Light is transmitted down the cable by repeatedly reflecting the light off the boundary between the fiber core and the sheath, until it reaches the end of the fiber where it is disbursed through specific lensing. Sheath Core

98. C O M P A N Y Fiber Heads The three types of fiber heads. Through beam, Diffuse, and Retroreflective (not very common). They operate on the same principal as of the standard photoelectric sensors.

99. C O M P A N Y Through Beam

100. C O M P A N Y Diffuse

101. C O M P A N Y Types of Fibers Standard fiber This fiber consist of a single core that is protected by a plastic sheath.

102. C O M P A N Y Types of Fibers Concentric fiber The Concentric fiber consists of a core fiber which is used to conduct light from the transmitter. The smaller surrounding fibers carry light back to the receiver. This allows for greater sensing accuracy and allows for installation of only one piece.

103. C O M P A N Y Specialized Photoelectric Sensors Focal point sensor (A-400) Spot Sensor (A-300) Color Mark Sensor (A-346, A-322) Luster Sensor (A-216) Clear Material Sensor (A-186, 196, 202)

104. C O M P A N Y Focal Point Sensor Focal point sensors are a reflective style sensor that have a narrow beam width and are designed to detect objects at the reflection point and nowhere else. They are used to detect objects at a specific distance. The light source and receiver accepts the strong beam of regular reflection which enables the sensor to detect small and dark objects Omron Page A-400

105. C O M P A N Y Focal Point Sensor EmitterReceiver Sensing Area EmitterReceiver

106. C O M P A N Y Spot Sensor The spot sensor sometimes refereed to as a convergent beam sensors. With this sensor the light source is positioned perpendicular to the object and the receiver is set at an acute angle to detect only diffuse light from the object. It avoids receiving directly reflected light. This sensor style detects differences in object surface condition, small objects, or objects in a pinpoint. Omron Page A-300 E3C-VM35R

107. C O M P A N Y Spot Sensor EmitterReceiver Sensing Area

108. C O M P A N Y Spot Sensor EmitterReceiverEmitterReceiver

109. C O M P A N Y Color Mark Sensor These sensors are designed to detect marks of varying color contrast on a common surface. They have a similar light source and receiver arrangement as spot sensors, but they have increased sensitivity to changes in color. They can detect a color mark by contrast to non- marked area rather than by direct color measurement. Omron Page A-346 E3M-V

110. C O M P A N Y Color Mark Sensor EmitterReceiver Sensing Area EmitterReceiver

111. C O M P A N Y Color Mark Sensor There are three types of light sources each gives a different range of sense. Incandescent lamps: Best for wide range of color conditions. (Shorter life than LED). Green LED: Green LED’s provide longer life than incandescent and provide sensitivity for a wider range of colors than red light sources. Red LED: Red LED’s respond to a limited number of color combinations, but give longer sensing distances. RGB: Combination of Red, Green, and Blue LED’s. Largest selection of colors.

112. C O M P A N Y Luster Sensor Unlike all the other sensors that detect the presence of an object, the luster sensor looks at the sheen (glossiness) of an object. Omron Page A-216

113. C O M P A N Y Clear Material Sensor Detection of clear material such as plastic and film could traditionally be done using a polarized retroreflective sensor. This works but may not always be reliable. A specialized sensor was created to allow for the detection of clear materials. Omron Page A-186,196,202

114. C O M P A N Y Chapter 3 Ultrasonic Sensors

115. C O M P A N Y Ultrasonic Sensors

116. C O M P A N Y Operation Ultrasonic sensors utilize high frequency sound energy (above the audible range - ultrasound) to measure distance or detect objects. These devices transmit a burst of ultrasound energy, then wait for a return echo. By precisely calculating the time distance can be determined. Electro Corp Cat Page 94

117. C O M P A N Y Targets should be perpendicular to the face of the sensor.

118. C O M P A N Y Roll Diameters: The axis of the roll should be perpendicular to the face of the sensor

119. C O M P A N Y Fluids: Should be stable and or static.

120. C O M P A N Y Solids: Must be dense enough to reflect sound energy

121. C O M P A N Y Chapter 4 Other common sensing technologies

122. C O M P A N Y Reed Sensors Reed sensors, or more commonly referred to as switches. Reed switches are commonly used on cylinders to indicate end of stroke position. They consist of two thin metal reeds which open and close when a magnet passes by. This design gives a very fast action(for mechanical switches) and produces a maintained signal as long as the magnet is present.

123. C O M P A N Y Physical Construction The reeds are always mounted in a nitrogen filled glass tube which may be enclosed in another housing for protection against breakage. The clean nitrogen atmosphere assures long contact life for greater reliability. The contact arrangement is always single- pole, single-throw and can be either N.O. or N.C.

124. C O M P A N Y Physical Construction

125. C O M P A N Y Magnetic Sensors Two styles: Variable Reluctance (Passive) Magneto Resistive (Active)

126. C O M P A N Y VRS Variable reluctance sensors are completely self powered sensing devices that do not require an external voltage source to operate. They are generally used to provide speed sensing data for feedback and control of rotary motion mechanical components, or devices. (Tachometers)

127. C O M P A N Y VRS The output of a VRS produces an AC voltage signal. This signal varies in amplitude and wave shape as the speed of the monitored device changes. The most commonly used with a metal gear. Other appropriate targets are bolt heads, keys, keyways, magnets, and holes in metal disks.

128. C O M P A N Y VRS A permanent magnet is the heart of the VRS sensor and establishes a fixed magnetic field. An output is generated by the changing strength of this field caused by the approach and departure of a ferrous metal target. This disturbance in the magnetic field varies the reluctance, or the “or the resistance of flow” in the magnetic field which in turn dynamically changes the strength of the field. This change in the magnetic field strength induces a current into a coil winding which is attached to the output terminals of the sensor.

129. C O M P A N Y VRS

130. C O M P A N Y Magneto Resistive Sensors Magneto Resistive sensors provide a square wave digital output driven by the same type of alternating – Presence and absence target presentation as that of the VRS. This sensor style does require a voltage source for operation, which is typically specified 5 – 15 VDC.

131. C O M P A N Y Magneto Resistive Sensors Magneto Resistive devices contain a highly sensitive bridge circuit which reacts to the movement of ferromagnetic gear teeth. This imbalance of the bridge circuit is amplified to create the output signal. Because these are power devices, there is virtually no low speed limitations with this style sensor.

132. C O M P A N Y Questions? Thank You!