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  • Takex America Inc Training Manual

    Industrial Automation Group

    Rayman

    Rev 1.0

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    2 | P a g e

    Table of contents 1) Sensing Technology ............................................................................................................................... 3

    2) Photoelectric Sensor .............................................................................................................................. 5

    a) Basic components of photo sensor

    b) Photoelectric sensor modes of detection ....................................................................................... 6

    c) Photoelectric selection sensor question ........................................................................................ 6

    d) Photoelectric sensor Types ............................................................................................................. 7

    i) Thru beam Sensors ................................................................................................................... 7

    ii) Diffuse ....................................................................................................................................... 9

    iii) Background Suppression ........................................................................................................ 10

    iv) Convergent ............................................................................................................................. 11

    v) Reflex ...................................................................................................................................... 12

    vi) Polarized Reflex ...................................................................................................................... 14

    vii) Fiber optics ............................................................................................................................ 15

    viii) Laser ........................................................................................................................................ 16

    ix) Color ....................................................................................................................................... 18

    x) Mark ........................................................................................................................................ 19

    xi) Chemical and Oil resistant ...................................................................................................... 21

    3) Ultrasonic Sensor ................................................................................................................................. 22

    4) Light Curtains…………………………………………………………………………………………………………………………………..23

    5) Hot and Cold Metal Sensor .................................................................................................................. 24

    6) Terminology ......................................................................................................................................... 26

    7) Application Table ................................................................................................................................. 31

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    1. Sensing Technology in Industrial Automation A sensor can be thought of as an automatic switch. Sensors have contributed significantly to recent advances in manufacturing technology. Using a sensor makes a process or system more automated and removes the need for a human operator intervention to monitor and control the situation. In all the major industrial detection applications, sensors are used for detecting presence, absence or distance of parts from or at a reference point. The object to be detected is referred to as a target. When a target is detected the function of the sensor is to change output which in turn will turn a load or turn off the load. Applications of detection sensor are as follows:

    1. Verifying the part have reached a certain position 2. Counting parts 3. Verifying proper placement of parts in the system 4. Making sure edge of part is within the specified position 5. Determining the size of the product 6. Verifying level of liquid or material

    The three main categories of sensors used in industrial automation are limit switches, proximity switches( Inductive, Capacitive, photoelectric) sensors, long distance sensing ( Photoelectric, ultrasonic) sensors. Limit switches use a mechanical actuator requiring the sensor to change its output when object is physically touching the switch. Sensors, such as photoelectric, inductive, capacitive, and ultrasonic, change the output when object is present, but not touching the sensor. In addition to the advantages and disadvantages of each, sensor technology has been well suited for certain applications. The table on next page elaborates the difference of the sensor technology.

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    Sensor Advantages Disadvantages Application Limit Switches

    • High current capacity

    • Low cost • Low tech

    • Requires physical contact

    • Very slow response • Contact bounce • Wear and tear

    • Interlocking • Basic end of

    travel

    Inductive

    • Resistance to harsh environments

    • Very predictable • Long life • Easy to install

    • Short distance up to 50 mm

    • Machine tool industry

    • Sensing metal objects

    Capacitive

    • Detects objects inside container

    • Can detect no- metallic targets

    • Very sensitive to extreme environmental changes

    • Level sensing

    Photoelectric

    • Senses all kinds of materials

    • Long life • Longest sensing range

    • Very fast response time

    • Lens subject to contamination

    • Sensing range affected by color and reflectivity of target object

    • Packaging • Material

    handling • Parts detection

    Ultrasonic

    • Senses all materials • Resolution • Repeatability • Sensitive to temperature changes

    • Anti-collision • Doors • Web • Level

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    2. Photoelectric Sensors Photoelectric Sensors (PS) use light to detect the presence or absence of an object. All Photo-sensors consist of the sensor, control unit, and output. The source is a light emitting diode that emits a powerful beam of infrared or visible light. The detector is typically a photo diode that senses the presence or absence of light. 2a. Basic components of Photo Sensor: Source LED Photodetector Lens (for source and detector) Power Circuit ( modulator and demodulator) Amplifier Output Circuit

    Amplifier

    Power Supply

    Modulator

    Source LED

    Photodetector

    Lens

    Target or Reflector

    Demodulator

    Output Detector Amplifier

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    2b. Photo Sensor modes of detection:

    Thru-beam (Through beam) Reflex (Retro-reflective / Polarized retro-reflective) Diffuse (Diffuse reflective)

    KEY POINT CONSIDERATION

    Range How far is the object to be detected? Environment How dirty or dark is the environment? Accessibility What accessibility is there to both sides of the object to be

    detected? Wiring Is wiring possible to one or both sides of the object. Size and color What is the size and the color of the object? Consistency Is the object consistent in size, shape, and reflectivity? Requirements What are the mechanical and electrical requirements? Output signal What kind of output is needed Logic function Are logic functions needed at the sensing point? Integration Is the system required to be integrated?

    2c. Photoelectric Selection questions Thru-beam, Reflex Diffuse Sensing Object 1. Size and shape

    2. Transparency( opaque, translucent, or transparent)

    3. Speed in ft/s or m/s ( V)

    1. Size and shape 2. Color 3. Material 4. Surface(textured or glossy) 5. Speed in ft/s or m/s (V)

    Sensor 1. Sensing distance (L) 2. Restriction of shape or size

    a. Sensor b. Retro-reflector

    3. Mounting a. Number of sensors b. mounting pitch

    4. Limitation of installation

    1. Sensing distance (L) 2. Restriction of shape and size 3. Mounting

    a. Number of sensors b. Pitch

    4. Limitation of installation

    Background 1. Color 2. Material 3. Surface

    Environment 1. Ambient temperature 2. Water, oil or chemicals

    presence 3. Other

    1. Ambient temperature 2. Water, oil or chemicals

    presence 3. Other

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    2d. Photoelectric Sensor Types Thru-beam Sensing

    The thru-beam method requires that the source and detector are positioned opposite each other and the light beam is sent directly from source to detector. When object passes between the emitter and receiver, the beam is broken, signaling detection of object. Thru-beam detection generally provides the lon