Introduction to sensors
- 1. Level I 1 Training Series: Level I
- 2. 2 Electrical InterfaceElectrical Interface The Back-end
- 3. 3 Electrical InterfaceElectrical Interface Divided into 2 areas: ◦ Operating voltage ◦ Output signal type Electrical Interface PowerPower SignalSignal
- 4. 4 OUTPUT SIGNAL TYPES Discrete ON or OFF YES or NO Analog Speed control Position information MIN MAX Electrical Interface SignalSignal
- 5. 5 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 PowerPower
- 6. 6 A DISCRETE SENSOR IS A SWITCH Electronics Sensing Side Front-end Electronics Power Wires Switch Electrical Interface
- 7. 7 Electronics BASIC SENSOR CIRCUIT Sensors with relay output + - Unlike a switch, sensors require power to operate Electrical Interface
- 8. 8 TYPES OF DISCRETE ELECTRICAL OUTPUTS Sensors of today use Solid-State outputs, not mechanical relays Today Yesterday PNP, 3-wire Relay NPN, 3-wire AC/DC, 2-wire Electrical Interface
- 9. 9 THE NPN & PNP OUTPUT Functions similar to a switch, But current only flows in one direction PNP Transistor Mechanical Switch Electrical Interface
- 10. 10 THE DIFFERENT TRANSISTORS What direction do you want current to flow? NPN Also called Sinking Electrical Interface PNP Also called Sourcing +--+
- 11. 11 PNP, 3-WIRE 1 4 + PNP Output 3 - Load Standard diagram form As shown in our catalog The Sensor The Load Connector Pins Electrical Interface
- 12. 12 PNP, 3-WIRE 1 4 + PNP Output 3 - Load Watching the current flow Sensors Power Output Signal Electrical Interface
- 13. 13 1 4 + NPN Output 3 - Load NPN, 3-WIRE Watching the current flow Sensors Power Output Signal Electrical Interface
- 14. 14 1 ~ 3 ~ Load 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
- 15. 15 QUICK REFERENCE: WIRING PNP & NPN N P N P N P + - Load First side of load Second side of load Switched side Positive Negative Sensor is PNP Electrical Interface
- 16. 16 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 1 4 + 3 - Load 1 ~ 3 ~ Load Electrical Interface
- 17. 17 NORMALLY OPEN (NO) VS. NORMALLY CLOSED (NC) Identifies the non-active state (target not present) of the sensor Electronics + - Normally Open Is it off (open)? Is it on (closed)? Electrical Interface
- 18. 18 NORMALLY OPEN (NO) VS. NORMALLY CLOSED (NC) Identifies the non-active state (target not present) of the sensor Electronics + - Is it off (open)? Is it on (closed)? Electronics + - Normally Closed Electrical Interface
- 19. 19 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
- 20. 20 ANALOG USES To provide absolute measurement or position information Measurement Position Electrical Interface
- 21. 21 ANALOG APPLICATIONS! 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
- 22. 22 ANALOG DATA 0 10987654321 Measurement Panel meters Control systems Electrical Interface
- 23. 23 ANALOG INFORMATION The many forms for representing measurement or position information 10 0 10 -10 5 -5 20 0 20 4 Voltage Current Digital Pulse Electrical Interface
- 24. 24 ANALOG VOLTAGE Information contained in varying voltage Maximum Voltage 0 10 987654321 Measurement Half VoltageNo Voltage 0 10 987654321 Measurement 0 10 987654321 Measurement Water Analogy Volt Meter Electrical Interface
- 25. 25 ANALOG CURRENT Information contained in varying Current 0 10 987654321 Measurement 0 10 987654321 Measurement 0 10 987654321 Measurement Maximum CurrentHalf CurrentNo Current Water Analogy Current Meter Electrical Interface
- 26. 26 DIGITAL PULSE Information contained in digital pulse timing 100.00 Maximum measurementHalf wayMinimum measurement 50.000.00Pulse Width Meter Start/Stop Electrical Interface
- 27. 27 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 PowerPower SignalSignal