measurements & instrumentation

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  • 1. HAI EVERYBODY
  • 2. By Pavithra.S
  • 3. UNDER THE TOPIC OF TRANSDUCER
  • 4.
  • 5. WHAT IS MEANT BY TRANSDUCER?.... TRANSDUCER IS DEFINED AS A DEVICE THAT RECEIVES ENERGY FROM ONE SYSTEM AND TRANSMITS TO ANOTHER. (WHICH CONVERTS PHYSICAL QUANTITY INTO ELECTRICAL SIGNAL)ITS ALSO CALLED AS PICKUP
  • 6. [Sensor means which detects/measures the device Example: thermometer SMART SENSOR WITH INTEGRATED ELECTRONICS THAT CAN PERFORM ONE OR MORE OF THE FOLLOWING FUNCTION. LOGIC FUNCTIONS TWO WAY COMMUNICATION MAKE DECISIONS..
  • 7. Usefulness of silicon technology in smart sensor
  • 8. a transduction element either includes thin metal films,zinc oxide & polymeric films integrated sensors provide significant advantages in terms of overall sizes & the ability to use small signals from the transduction element. IC (integrated circuit) industry will get involved in smart sensor if a very large market can be captured &the production of smart sensor doesnt require non-standard processing steps..
  • 9. Signal domain examples Radiant Light intensity,polarization,phase, wavelength mechanical Force,pressure,flow,vaccum, thickness thermal Temperature,temp gradient,thickness chemical Concentration,toxicity,pH magnetic Field intensity,flux
  • 10. Signal domain examples Radiant Photo voltaic effect,photo electric effect,photo magneto-electric effect,photo conductivity mechanical Piezo resistivity thermal Seebeck effect,temperatre dependence of conductivity
  • 11. Radian signal domain:Radiant silicon can be used to connect a sensor for sensing wide range of radiant signal from gamma rays to infrared. Silicon can be used for the fabrication of photoconductors,phototransistor or to detect nuclear radition.
  • 12. silicon can be used for measuring force and pressure because of the piezo resistance effect. This effect is large because the average mobility of electrons and holes in siliconis strongly affected by the application of strain silicon can alo be used for the measurement of air or gas velocities.
  • 13. Smart sensor also enhances the following applications: self calibration- adjusting some parameter of sensor during fabrication. -calibration is needed bcoz, their adjustments usually change with the time that needs the device to be removed & recalibrated.thee problems are solved by smart sensor(has the the correction functions in memory).
  • 14. computation- it also allows one to obtain the average, varience & standard deviation for set of measurement.this can be easily done done using smart sensor - to compensate for the environmental change such as temperature. communication- communication means of exchanging or conveying information.
  • 15. multisensing a single smart sensor can measure pressure ,temperature,humidity, gas flow &infra red. System reliability System reliability is significantly improved due to the utilization of smart sensors
  • 16. Non linearity Cross sensitive(shows an un desairable sensitivity to strain &temperature ) Offset(well reduced by sensitivity reduction method) Parameter drift & componeent values(these are functions of time it can be solved by automatic calibration)
  • 17. Thermal signal domain- measurement of temperature by using two bipolar transistors with a cons.ratio of emitter current. Magnetic signal domain-silicon is a non magnetic material. But it can be used for the construction of hallplates &transistor structure that are sensitive to magnetic fields. Chemical signal domain-ISFET is suitable for such application.
  • 18. The presence in smart sensor has led to corrections for different un desirable sensor characteristics which include, input offset &span variation, non linearity & cross sensitivity .as these are carried in software no additional software is required thus calibration becomes an electronic process
  • 19. Sensor inside hardware is more complex in the sensor on the other hand it is outside the sensor. Reduced cost of bulk cables & connectors To reduce the cost of bulk cables & connectors needed to connect different blocks
  • 20. Block diagram
  • 21. Transducer 1 Transducer 1 Transducer 1 Transducer 1 A1 A1 A1 A1 S/H1 S/H2 S/H3 S/H4 ANAL OG MUX ADC Offset correction& temp drift compensation sample& Hold control processor Serial communicatio n memory DAC

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