EKT314/4 Electronic Instrumentation Week 3 Chapter 2: Transducer

Classification Applications Definition Physics Computer Science Revise….. Classification Applications Definition Physics Computer Science Transducer Finite State EKT314/4 - Electronic Instrumentation

Classification Applications Definition Physics Computer Science Transducer Finite State EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Motion Applications Position Pressure Examples of sensor Selected sensor picture Sensor characteristics Sensor operation circuitry Sensor-DAQ connection Motion Applications Position Pressure Proximity EKT314/4 - Electronic Instrumentation

NI USB-6008/6009 DAQ ANALOG DIGITAL GND – 01 AI0 – 02 AI4 – 03 AO0 – 14 AO1 – 15 GND – 16 32 – GND 31 – +5V 30 – +2.5V 29 – PFI0 28 – P1.3 27 – P1.2 26 – P1.1 25 – P1.0 24 – P0.7 23 – P0.6 22 – P0.5 21 – P0.4 20 – P0.3 19 – P0.2 18 – P0.1 17 – P0.0 -8 analog inputs- -2 analog outputs- -12 digital I/O- -32-bit counter- EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Switches RTD Temperature Thermocouple Infrared Thermistor EKT314/4 - Electronic Instrumentation

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

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

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

Temperature Sensor Circuit of Sensor RTD EKT314/4 - Electronic Instrumentation

Temperature Sensor Connection to NI DAQ TO ANALOG INPUT OF DAQ EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

PIEZOELECTRIC SENSORS Shock Sensor Vibration Triaxial Sensors Accelerometer Handprobes EKT314/4 - Electronic Instrumentation

Vibration Sensor Piezoelectric Sensors EKT314/4 - Electronic Instrumentation

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

Vibration Sensor Circuit of Sensor EKT314/4 - Electronic Instrumentation

Vibration Sensor Connection to NI DAQ DAQ ANALOG INPUT EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

MEMS mass-flow sensors Mass Air Flow Sensor Flow Turbine Flow sensor Ultrasonic Flow meter Gas Flow Sensor EKT314/4 - Electronic Instrumentation

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. EKT314/4 - Electronic Instrumentation

Flow Sensor Characteristic of Sensor EKT314/4 - Electronic Instrumentation

Flow Sensor Circuit of Sensor EKT314/4 - Electronic Instrumentation

Flow Sensor Connection to NI DAQ DAQ ANALOG INPUT EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Load Cell Force Sensor Piezoforce sensor Force Elastic element Magento elastic Hydrolic Load cell EKT314/4 - Electronic Instrumentation

Force Sensor Hydrolic Load Cell Sensor EKT314/4 - Electronic Instrumentation

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

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Resistive Humidity Sensor Capacitive Humidity sensor In capacitive humidity sensors, the effect of humidity on the dielectric constant of a polymer or metal oxide material is measured In resistive humidity sensors, the 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. In thermal conductivity humidity sensors, the change in thermal conductivity of air due to humidity is measured. These sensors measure absolute humidity rather than relative humidity.[1] Thermal conductivity humidity sensor EKT314/4 - Electronic Instrumentation

Humidity Sensor Resistive humidity Sensor EKT314/4 - Electronic Instrumentation

Humidity Sensor Characteristic of Sensor the 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

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Ultrasonic Level Sensor Optical Ultrasonic Level Sensor Level Microwave Resistive Chain Ultrasonic level sensors are used for non-contact level sensing of highly viscous liquids, as well as bulk solids. Optical 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. Microwave sensors are ideal for use in moist, vaporous, and dusty environments as well as in applications in which temperatures vary Resistive chain level sensors are similar to magnetic float level sensors in that a permanent magnet sealed inside a float moves up and down a stem in which closely spaced switches and resistors are sealed. When the switches are closed, the resistance is summed and converted to current or voltage signals that are proportional to the level of the liquid. Magneto resisitive EKT314/4 - Electronic Instrumentation

Level Sensor Optical level Sensor EKT314/4 - Electronic Instrumentation

Level Sensor Characteristic of Sensor Optical 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

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Laser Infrared Motion CCD Acoustic (sound) Vibration Motion can be detected by: sound (acoustic sensors), opacity (optical and infrared sensors and video image processors), geomagnetism (magnetic sensors, magnetometers), reflection of transmitted energy (infrared laser radar, ultrasonic sensors, and microwave radar sensors), electromagnetic induction (inductive-loop detectors), and vibration (triboelectric, seismic, and inertia-switch sensors). Acoustic sensors are based on: electret effect, inductive coupling, capacitive coupling, triboelectric effect, piezoelectric effect, and fiber optic transmission. Radar intrusion sensors have the lowest rate of false alarms. Vibration EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Solid State Pressure Sensor Piezoresistive Pressure Sensor Bourdon tube Bellows Pressure Solid State Pressure Sensor x Piezoresistive Pressure Sensor EKT314/4 - Electronic Instrumentation

Pressure Sensor Piezoresistive Sensor EKT314/4 - Electronic Instrumentation

Pressure Sensor Characteristic of Sensor In 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

Pressure Sensor Circuit of Sensor EKT314/4 - Electronic Instrumentation

Pressure Sensor Connection to NI DAQ DAQ ANALOG INPUT EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

Force Humidity Flow Level Vibration Motion Applications Position Speed Temperature Position Speed Pressure Proximity EKT314/4 - Electronic Instrumentation

EKT314/4 Electronic Instrumentation Week 3 End