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EKT314/4Electronic
InstrumentationWeek 3
Chapter 2: Transducer
EKT314/4 - Electronic Instrumentation 2
Transducer
Physics ComputerScience
FiniteState
Definition
Classification
Applications
Revise…..
EKT314/4 - Electronic Instrumentation 3
Transducer
Physics ComputerScience
FiniteState
Definition
Classification
Applications
EKT314/4 - Electronic Instrumentation 4
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 5
Applications
Flow
ForceHumidity
Position
Pressure
Motion
LevelExamples of sensor
Selected sensor picture
Sensor characteristics
Sensor operation circuitry
Sensor-DAQ connection
Proximity
EKT314/4 - Electronic Instrumentation 6
NI USB-6008/6009 DAQ
-8 analog inputs--2 analog outputs-
-12 digital I/O--32-bit counter-
ANALOG DIGITALGND – 01AI0 – 02AI4 – 03
GND – 04AI1 – 05AI5 – 06
GND – 07AI2 – 08AI6 – 09
GND – 10AI3 – 11AI7 – 12
GND – 13AO0 – 14AO1 – 15GND – 16
32 – GND31 – +5V 30 – +2.5V29 – PFI028 – P1.327 – P1.226 – P1.125 – P1.024 – P0.723 – P0.622 – P0.521 – P0.420 – P0.319 – P0.218 – P0.117 – P0.0
EKT314/4 - Electronic Instrumentation 7
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 8
Switches
Temperature
Infrared
RTD
Thermocouple
Thermistor
EKT314/4 - Electronic Instrumentation 9
Temperature Sensor
RTD –Resistance Temperature Detector
Common Resistance Materials for RTDs:•Platinum (most popular and accurate)•Nickel•Copper•Balco (rare)•Tungsten (rare)
EKT314/4 - Electronic Instrumentation 10
Temperature Sensor
Characteristic of Sensor
• Resistance Temperature Detectors or RTDs for short, are wire wound and thin film devices
• measure temperature because of the physical principle of the positive temperature coefficient of electrical resistance of metals.
•The hotter they become, the larger or higher the value of their electrical resistance.
EKT314/4 - Electronic Instrumentation 11
Temperature Sensor Characteristic of Sensor
• RTD’s are generally more expensive to manufacture or purchase than thermocouples.
♦ Since the RTD circuit is just a resistance circuit, no special extension leadwires or connectors are required making this portion of the circuit less expensive than that of a thermocouple.
♦ Although some types of RTD elements are rated to fairly high temperatures (650°C (1202°F)), they become quite fragile at temperatures above 320°C (600°F). A RTD sensor will not hold up well at these elevated temperatures if there is any vibration present. ♦ The tolerance or accuracy of an RTD generally decreases as temperature increases.
EKT314/4 - Electronic Instrumentation 12
Temperature Sensor Circuit of Sensor
RTD
EKT314/4 - Electronic Instrumentation 13
Temperature Sensor
Connection to NI DAQ
TO ANALOG INPUT
OF DAQ
EKT314/4 - Electronic Instrumentation 14
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 15
PIEZOELECTRIC SENSORS
Vibration
Accelerometer
Shock Sensor
Triaxial Sensors
Handprobes
EKT314/4 - Electronic Instrumentation 16
Vibration Sensor
Piezoelectric Sensors
EKT314/4 - Electronic Instrumentation 17
Vibration Sensor Characteristic of Sensor
The rugged, solid-state construction of industrial piezoelectric sensors enables them to operate under most harsh environmental conditions. They are unaffected by dirt, oil, and most chemical atmospheres. They perform well over a wide temperature range and resist damage due to severe shocks and vibrations. Most piezoelectric sensors used in vibration monitoring today contain internal amplifiers.
The piezoelectric element in the sensor produces a signal proportional to acceleration. This small acceleration signal can be amplified for acceleration measurements or converted (electronically integrated) within the sensor into a velocity or displacement signal. The piezoelectric velocity sensor is more rugged than a coil and magnet sensor, has a wider frequency range, and can perform accurate phase measurements.
EKT314/4 - Electronic Instrumentation 18
Vibration Sensor
Circuit of Sensor
EKT314/4 - Electronic Instrumentation 19
Vibration Sensor
Connection to NI DAQ
DAQ ANALOG INPUT
EKT314/4 - Electronic Instrumentation 20
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 21
MEMS mass-flow sensors
FlowUltrasonic Flow meter
Mass Air Flow
Sensor
Turbine Flow sensor
Gas Flow Sensor
EKT314/4 - Electronic Instrumentation 22
Flow Sensor
Mass Air Flow(MAF) The Mass Air Flow(MAF) Sensor converts
the amount of air drawn into the engine into a voltage signal.
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Flow Sensor
Characteristic of Sensor
EKT314/4 - Electronic Instrumentation 24
Flow Sensor
Circuit of Sensor
EKT314/4 - Electronic Instrumentation 25
Flow Sensor
Connection to NI DAQ
DAQ ANALOG INPUT
EKT314/4 - Electronic Instrumentation 26
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 27
Piezoforce sensor
Force
Magento elastic
Load Cell Force
Sensor
Elastic element
Hydrolic Load cell
EKT314/4 - Electronic Instrumentation 28
Force Sensor
Hydrolic Load Cell Sensor
EKT314/4 - Electronic Instrumentation 29
Force Sensor
Characteristic of Sensor
The hydraulic load cellis a device filled with a liquid (usually oil) which has a pre-load pressure. Application of the force to the loading member increases the fluid pressure which is measured by a pressure transducer or displayed on a pressure gauge dial via a Bourdon tube
EKT314/4 - Electronic Instrumentation 30
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 31
Resistive Humidity Sensor
Humidity
Capacitive Humidity sensor
Thermal conductivity
humidity sensor
EKT314/4 - Electronic Instrumentation 32
Humidity Sensor
Resistive humidity Sensor
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Humidity Sensor
Characteristic of Sensorthe change in electrical resistance of a material due to humidity is measured.[1] Typical materials are salts and conductive polymers. Resistive sensors are less sensitive than capacitive sensors - the change in material properties is less, so they require more complex circuitry. The material properties also tend to depend both on humidity and temperature, which means in practice that the sensor must be combined with a temperature sensor. The accuracy and robustness against condensation vary depending on the chosen resistive material. Robust, condensation-resistant sensors exist with an accuracy of up to ±3% RH.
EKT314/4 - Electronic Instrumentation 34
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 35
Optical
Level
Resistive Chain
Ultrasonic Level
Sensor
Microwave
Magneto resisitive
EKT314/4 - Electronic Instrumentation 36
Level Sensor
Optical level Sensor
EKT314/4 - Electronic Instrumentation 37
Level Sensor
Characteristic of SensorOptical sensors are used for point level sensing of sediments, liquids with suspended solids, and liquid-liquid interfaces.
These sensors sense the decrease or change in transmission of infrared light emitted from an infrared diode (LED).
With the proper choice of construction materials and mounting location, these sensors can be used with aqueous, organic, and corrosive liquids.
EKT314/4 - Electronic Instrumentation 38
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 39
Laser
Motion
Acoustic (sound)
Infrared
CCD
Vibration
EKT314/4 - Electronic Instrumentation 40
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 41
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 42
Bourdon tube
Pressure
x
Bellows
Solid State Pressure Sensor
Piezoresistive
Pressure Sensor
EKT314/4 - Electronic Instrumentation 43
Pressure Sensor
Piezoresistive Sensor
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Pressure Sensor
Characteristic of SensorIn piezoresistive sensors, pressure changes the resistance by mechanically deforming the sensor, enabling the resistors in a bridge circuit, for example, to detect pressure as a proportional differential voltage across the bridge.
Conventional resistive pressure measurement devices include film resistors, strain gauges, metal alloys, and polycrystalline semiconductors
EKT314/4 - Electronic Instrumentation 45
Pressure Sensor
Circuit of Sensor
EKT314/4 - Electronic Instrumentation 46
Pressure Sensor
Connection to NI DAQ
DAQ ANALOG INPUT
EKT314/4 - Electronic Instrumentation 47
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 48
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4 - Electronic Instrumentation 49
Temperature
Vibration
Applications
Flow
ForceHumidity
Position
Pressure
Motion
Level
Speed
Proximity
EKT314/4Electronic
Instrumentation
Week 3End
