1. TGT pramono

2. Pokok bahasan 1.Penyiapan instrumen penelitian fisik 2.Penyusunan paremeter fisik 3.Pengumpulan data 1 4.Pengumpulan data 2 5.Input data 6.Data cleaning/validasi 7.Pengolahan data fisik 8.Analisis data fisik

3. Penyiapan Instrumen Mengapa perlu?

4. Gaya berpikir

5. Lecture 35 Instrumentation Examples

6. Lecture 36 Strain Measurements Strain gauge

7. Lecture 37 Non-destructive Testing Ultrasound transducer

8. Lecture 38 Automotive Sensors Oxygen Sensor Airflow Sensor Water Temperature Oil Pressure Accelerometer CO Sensor

9. Lecture 39 Biomedical Ultrasound Transducer

10. Lecture 310 What other examples can you think of?

11. Lingkungan (fisik) EC meter  EC: mikro mhos/cm2 pH meter  keasaman-kebasaan DO meter  oksigen terlarut COD  Turbidity meter  Kekeruhan Ring infiltrometer  infiltrasi  permeabilitas tanah Metode: Auger hole  permeabilitas tanah Current meter  kecepatan aliran AWLR  automatic water level recorder

12. Stafgauge = pielscall = papan duga  tinggi muka air ARR  automatic rainfall recorder Lesi meter  perkolasi Pan A  evaporasi air bebas Anemometer  kecepatan angin Camblestoke  radiasi matahari Gelas ukur  volumetrik Soil humidity meter  kelembaban tanah OHM meter (Ω)  resitivity/tahanan (ketidakhantaran listrik) lawannya daya hantar (electric conductivity  mhos ( )

13. Lecture 313 A Typical Instrumentation System Sensor Amplifier A/D Converter Computer

14. Lecture 314 Instrumentation System Sensor-converts the measured value into an electrically useful value. Amplifier-”conditions” the signal from the sensor. A/D Converter-converts the signal into a digital format. Computer-processes, displays, and records the signal.

15. Lecture 315 Sensor The output of a sensor is proportional to the quantity of interest. The sensor output may be a – voltage or current (temperature, pressure) – resistance (strain gauge) – frequency (accelerometer)

16. Lecture 316 Amplifier The output of the amplifier is (usually) a voltage. The gain of the amplifier is set so that the voltage falls between lower and upper limits (for example, -10V to 10V).

17. Lecture 317 A/D Converter Analog-to-digital conversion consists of two operations: – Sampling: measuring the voltage signal at equally spaced points in time. – Quantization: approximating a voltage using 8 or 16 bits.

18. Lecture 318 Instrumentation Issues Noise Signal bandwidth Sampling Amplifier characteristics Feedback Real-time processing Control systems

19. Lecture 319 Noise Signal Signal + Noise

20. Lecture 320 Sources of Noise Thermal noise caused by the random motion of charged particles in the sensor and the amplifier. Electromagnetic noise from electrical equipment (e.g. computers) or communication devices. Shot noise from quantum mechanical events.

21. Lecture 321 Effects of Noise Reduces accuracy and repeatability of measurements. Introduces distortion in sound signals. Introduces errors in control systems.

22. Lecture 322 What to Do? How can we eliminate or reduce the undesirable effects of noise? Grounding/shielding electrical connections Filtering (smoothing) Averaging several measurements

23. Lecture 323 Signal Bandwidth Conceptually, bandwidth is related to the rate at which a signal changes: High BW Low BW

24. Lecture 324 Bandwidth and Sampling A higher bandwidth requires more samples/second: High BW Low BW

25. Lecture 325 Bandwidth Limitations Every component in the instrumentation system has bandwidth limitations: Sensors do not respond immediately to changes in the environment. The amplifier output does not change immediately in response to changes in the input. The A/D converter sampling rate is limited.

26. Lecture 326 Effects of BW Limitations Sensor Output Amplifier Output

27. Lecture 327 Amplifier Characteristics Amplifiers are characterized in terms of attributes such as: Gain Bandwidth and/or frequency response Linearity Harmonic distortion Input and output impedance

28. Lecture 328 Op Amps One commonly used type of amplifier is the Operational Amplifier (OpAmp). Op Amps have differential inputs: output voltage is the amplified difference of two input voltages. Op Amps have very large gains (>10 3 ).

29. Lecture 329 Op Amps (cont.) Most op amp circuits use negative feedback. Op amp circuits can be designed to: – Provide voltage gain or attenuation. – Convert current to voltage. – Integrate or differentiate. – Filter out noise or interference.

30. Lecture 330 Feedback Often, sensors measure quantities associated with systems. The sensor output is used to control the system in a desired manner.

31. Lecture 331 Example: Industrial Process Control In many manufacturing processes (integrated circuits, for example) temperatures must be closely controlled. Feedback can be used to maintain a constant temperature.

32. Lecture 332 Temperature Control The Control System sets the current supplied to the heating elements in the furnace to keep the material temperature at the desired value. Desired Temperature Control System Furnace and Material Temperature Sensor

33. Lecture 333 A car cruise control is a feedback system. How does it work?

34. Lecture 334 Benefits of Feedback Provides stability with respect to changes in system parameter values. Helps to obtain a (nearly) linear response from non-linear components. Can be used to change the characteristics of a system under control.

35. tq