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Training Series: Level I Introduction to Sensors Level I.

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Presentation on theme: "Training Series: Level I Introduction to Sensors Level I."— Presentation transcript:

1 Training Series: Level I Introduction to Sensors Level I

2 Course Topics Sensors Definition Sensor Building Blocks –Electrical Interface Tell me about it: –Sensing Technology I see it: –Housings Looks are everything: Training Series: Level I

3 Sensor Definitions What are we talking about ?

4 What is a Sensor? Used in Industrial Automation: Electrical device capable of identifying change within an automated process. Sometimes… Sensor = Switch Sometimes… Sensor = Switch Sensor Definitions

5 Sensor Uses Sensors in our world –Automatic opening doors –Grocery check-out conveyer shut-off –Safety sensors on garage doors Sensors in Manufacturing –Part position verification –Counting products –Liquid level control –Quality control inspection –Personal safety systems Sensor Definitions

6 Sensor Building Blocks The three major components: The sensing side Front-end Housing The electrical side Back-end Sensor Definitions

7 Building Block Concept Sensor Definitions Sensing technology Electrical interface Housing most any

8 The Building Blocks Front-end - Sensing Five technology choices: Inductive Optical Capacitive Magnetic Mechanical Selection base on: Application Sensor Definitions

9 The Building Blocks Back-end – Electrical Options: Electrical voltage –AC/DC –DC Output type –Discrete (on-off, like a switch) –Analog Selection base on: Control System Sensor Definitions

10 The Building Blocks The Sensors Housings –Material Options: Metal (nickel-plated brass) Stainless steel Aluminum Plastic –Shape (mounting style): Tubular Block Selection base on: Environment Sensor Definitions

11 The Building Blocks and the real world Sensing Housing Electrical Application Control System Environment Sensor Definitions

12 Training Series: Level I Electrical Interface The Back-end

13 Electrical Interface Divided into 2 areas: –Operating voltage –Output signal type Electrical Interface Power Signal

14 Output Signal Types Discrete –ON or OFF –YES or NO Analog –Speed control –Position information Electrical Interface Signal

15 Operating Voltage Direct Current (DC) –Current flows in only ONE direction –Safe, easy-to-handle power source Alternating Current (AC) –Current changes direction 60 times a second –Readily available Electrical Interface Power

16 Basic Electrical Principals What is electricity? –Interesting fact: Electron flow is similar to water flow We will use this analogy during our class Electrical Interface Flow (current) or potential flow (voltage) of electrons

17 Basic Series Circuit Using Water Analogy: Water Tank Water Valve Hydro motor Potential Flowing Electrical Interface

18 Basic Series Circuit Electronics: Potential Flowing Battery Switch Electric Motor Basic ON or OFF operation Electrical Interface

19 A discrete Sensor is a Switch Sensing Side Front-end Electronics Power Wires Switch Electrical Interface

20 Basic Sensor Circuit Sensors with relay output Unlike a switch, sensors require power to operate Electrical Interface

21 Types of discrete electrical outputs Sensors of today use Solid-State outputs, not mechanical relays TodayYesterday –PNP, 3-wire Relay –NPN, 3-wire –AC/DC, 2-wire Electrical Interface

22 The NPN & PNP output Functions similar to a switch, But current only flows in one direction PNP Transistor Mechanical Switch Electrical Interface

23 The Different Transistors What direction do you want current to flow? NPN Also called Sinking Electrical Interface PNP Also called Sourcing

24 PNP, 3-wire Standard diagram form As shown in our catalog The Sensor The Load Connector Pins Electrical Interface

25 PNP, 3-wire Watching the current flow Sensors Power Output Signal Electrical Interface

26 NPN, 3-wire Watching the current flow Sensors Power Output Signal Electrical Interface

27 The 2-wire AC/DC output Functions similar to a switch, But with a small leak Sensors Power Supply from leakage current Output Signal Triac Electrical Interface

28 Quick Reference: wiring PNP & NPN N P N P N P First side of load Second side of load Switched side Positive Negative Sensor is PNP Electrical Interface

29 If given a choice, which discrete sensor type should I choose? PNP or NPN, 3-wire -Fewer interface problems -Largest selection - Lowest unit costs AC/DC, 2-wire - Many interface issues -Smaller selection -Susceptible to noise 1st CHOICE 2nd CHOICE Electrical Interface

30 Normally Open (NO) vs. Normally Closed (NC) Identifies the non-active state (target not present) of the sensor Normally Open Is it off (open)? Is it on (closed)? Electrical Interface

31 Normally Open (NO) vs. Normally Closed (NC) Identifies the non-active state (target not present) of the sensor Is it off (open)? Is it on (closed)? Normally Closed Electrical Interface

32 Analog Outputs Unlike a discrete output with two defined states, analog signals have an infinite number of states. Discrete Analog On Off Voltage Time Max Min Voltage Time Electrical Interface

33 Analog Uses To provide absolute measurement or position information Measurement Position Electrical Interface

34 Analog Applications! What can you do with measurement information? –Measure thickness –Position feedback –Measure tool wear –Null out machine wear –Null out thermal expansion –Verify die position –Verify bend radius –Part profiling –Stack height –Spool diameter –Rotational position –Liquid level –Sort parts –Determine part orientation –Measure vibration –Measure straightness –Hydraulic or pneumatic cylinder position Expanding possibilities Expanding possibilities Electrical Interface

35 Analog Data We know analog information provides: –Measurement information –Position information What devices use analog information? Panel metersControl systems Electrical Interface

36 Analog Information The many forms for representing measurement or position information Voltage Current Digital Pulse Electrical Interface

37 Analog Voltage Information contained in varying voltage Maximum VoltageHalf Voltage Water AnalogyVolt Meter Electrical Interface

38 Analog Current Information contained in varying Current Maximum CurrentHalf Current Water AnalogyCurrent Meter Electrical Interface

39 Digital Pulse Information contained in digital pulse timing Maximum measurementHalf wayMinimum measurement Pulse Width Meter Start/Stop Electrical Interface Measurement range

40 Electrical Interface REVIEW Operating voltage: Sensor Power –DC: Safest –AC: Most available Output signal types –Discrete PNP, 3-wire NPN, 3-wire AC/DC 2-wire –Analog Voltage Current Digital pulse Electrical Interface Power Signal

41 Training Series: Level I Sensing Technologies

42 Non- Contact –No physical contact with target –Preferred method for sensing end products Contact –Contact with target –Simplest method available Sensing Technologies

43 Contact Sensing Mechanical switch –Contact with plunger opens electrical contacts Contact Sensing Technologies

44 Non-Contact Popular sensing technologies –Inductive Sensors Metal targets –Optical Sensors Target capable of reflecting or blocking light –Capacitive Sensors Liquids/solids –Magnetic Field Sensors Magnets Sensing Technologies

45 Inductive When voltage is applied, an electromagnetic field is generated and extends out the face of the sensor. When metal enters the sensing zone, an eddy current is induced in the metal. The change in eddy current is detected and the sensor’s output is energized. Sensing Technologies

46 Two basic Sensing types –Flush mount Shorter range Sensor can be buried in metal –Non-flush mount Longer range Sensor can NOT be buried in metal Inductive Sensing Technologies

47 Optical Regardless of the operating mode, all optical sensors share the same operating principle: Light emitter Visible red Laser Infrared Light receiver Operation Emits a light beam then detects or measures changes in received light. Sensing Technologies

48 Optical Optical sensors offer three main sensing modes –Thru-beam –Retroreflective –Diffuse Note: There are other sensing modes available, but they are covered in other courses. Sensing Technologies

49 Optical: Thru-Beam Separate emitter and receiver Beam-break operation Target blocks beam EmitterReceiver Great for long range and dirty environments Sensing Technologies

50 Optical: Retroreflective Emitter and receiver in one unit Requires a reflector Beam-break operation Target block light beam Reflector Emitter Provides good range in well defined area Sensing Technologies

51 Emitter and receiver in one unit Convenient stand-alone design Beam-make operation Light reflects off target Optical: Diffuse Simple point and shoot operation Target Sensing Technologies

52 Capacitive Detects target based on density Simple point and shoot operation Target Electrostatic field established Target detected when field properties change Sensing Technologies

53 Magnetic Detects magnetic field Magnetic field can travel through aluminum Used extensively with pneumatic cylinders Magnet N S Sees through aluminum Sensing Technologies

54 Sensing Technologies Head-to-Head Mechanical: Inductive: Optical, Thru-beam: Optical, Retro: Optical, Diffuse: Capacitive: Magnetic: Popular, simple Rugged, cost-effective Long range Mid range Short range Liquid & bulk targets Pneumatic cylinders Sensing Technologies

55 Training Series: Level I Housings Physical looks

56 Housing Function Protection from environment Mounting provisions Electrical connection Housings

57 Protection from environment –Multiple degrees of protection liquids IP65: Protects against water mist IP67: Protects against temporary immersion IP68: Protects against continuous immersion –Multiple level of physical abuse Metal housing Plastic housing Housings

58 Mounting Provisions Depends on shape of housing –Tubular Popular for short range sensors Range adjustments made by moving sensor in and out –Block Popular for optical sensors Easy to align horizontally and vertically Housings

59 Inductive Sensor Tubular Housings Easy mounting and range adjustment Optical Sensor Capacitive Magnetic Housings

60 Block Housings Provides thru-holes for mounting bolts Allows for easy beam alignment Inductive Sensor Optical Sensor Housings

61 Combination Housings Combination of tubular and block housings Inductive Sensor Optical Sensor Housings

62 Application Specific Shapes Inductive Sensor Optical Sensor Magnetic Hydraulic Cylinder Ring Sensor Valve Position Clamp Position Slot Sensors Windows Fiber-optics Pneumatic Cylinders Housings

63 Electrical Connection Cable Out version –Economical: no additional cable to purchase –Difficult to replace sensor Connector version –Cost: must purchase mating cable –Much easier to replace sensor Housings

64 Cable Connection Options Cable Lengths –Standard lengths: 2m, 3m & 5m Jacket Material –PVC: Standard, low cost jacketing –PuFlex: For flexing applications Housings

65 Connector Options Industry standard connector sizes: –Micro (M12) Most popular, mid-size Available in 3, 4, 5 and 8 pins –Nano (M8) Smallest size Available in 3 and 4 pins –Mini Largest size Available in 3 and 4 pins Housings

66 Sensor Housings REVIEW Protection from environment –IP65, IP67, IP68 Mounting provisions –Tubular, Block, Combination, Application specific shapes Electrical connection –Cable out and connectors Housings

67 Sensor Fundamentals Sensing Housing Electrical Application Control System Environment Sensors Definitions Questions & Answers

68 Training Series: Level I Sensor Basics


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