Mikroprosesor dan Antarmuka (13) sistem akuisisidata

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Mikroprosesor dan Antarmuka (13) sistem akuisisidata

  1. 1. S i stem Akuisisi D at a Bambang Heru Iswanto, Dr.rer.nat Sesion #13 Jurusan Fisika Fakultas Matematika dan Ilmu Pengetahuan Alam
  2. 2. Outline <ul><li>PC-based Data Acquisition System Overview </li></ul><ul><li>Data Acquisition System Introduction I </li></ul><ul><li>Data Acquisition System Introduction II </li></ul><ul><li>Data Acquisition System Block Diagram </li></ul><ul><li>Transducers </li></ul><ul><li>Transducers and Actuators </li></ul><ul><li>Signal Conditioning </li></ul><ul><li>Data Acquisition </li></ul><ul><li>A/D Converter: Sampling RateA/D Converter: Throughput </li></ul><ul><li>A/D Converter: Range </li></ul><ul><li>A/D Converter: Resolution </li></ul>© 2010 Universitas Negeri Jakarta | www.unj.ac.id | 06/02/11
  3. 3. © 2010 Universitas Negeri Jakarta | www.unj.ac.id | Mikrokontroler dan Interfacing S i stem akuisisi dat a 06/02/11
  4. 4. PC-based Data Acquisition System Overview <ul><li>In the last few years, industrial PC I/O interface products have become increasingly reliable, ccurate and affordable. PC-based data acquisition and control systems are widely used in industrial and laboratory applications like monitoring, control, data acquisition and automated testing. </li></ul><ul><li>Selecting and building a DA&C (Data Acquisition and Control) system that actually does what you want it to do requires some knowledge of electrical and computer engineering. </li></ul><ul><ul><ul><li>• Transducers and actuators </li></ul></ul></ul><ul><ul><ul><li>• Signal conditioning </li></ul></ul></ul><ul><ul><ul><li>• Data acquisition and control hardware </li></ul></ul></ul><ul><ul><ul><li>• Computer systems software </li></ul></ul></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  5. 5. Data Acquisition System Introduction I <ul><li>A data acquisition system consists of many components that are integrated to: </li></ul><ul><li>Sense physical variables (use of transducers) </li></ul><ul><li>Condition the electrical signal to make it readable by an A/D board </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  6. 6. Data Acquisition System Introduction II <ul><li>Convert the signal into a digital format acceptable by a computer </li></ul><ul><li>Process, analyze, store, and display the acquired data with the help of software </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  7. 7. Data Acquisition System Block Diagram 06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  8. 8. Transducers <ul><li>Sense physical phenomena and translate it into electric signal. </li></ul><ul><li>Displacement </li></ul><ul><li>Level </li></ul><ul><li>Electric signals </li></ul><ul><li>ON/OFF switch </li></ul><ul><li>Temperature </li></ul><ul><li>Pressure </li></ul><ul><li>Light </li></ul><ul><li>Force </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  9. 9. Transducers and Actuators <ul><li>A transducer converts temperature, pressure, level, length, position, etc. into voltage, current, frequency, pulses or other signals. </li></ul><ul><li>An actuator is a device that activates process control equipment by using pneumatic, hydraulic or electrical power. For example, a valve actuator opens and closes a valve to control fluid rate. </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  10. 10. Signal Conditioning <ul><li>Signal conditioning circuits improve the quality of signals generated by transducers before they are converted into digital signals by the PC's data-acquisition hardware. </li></ul><ul><li>Examples of signal conditioning are signal scaling, amplification, linearization, cold-junction compensation, filtering, attenuation, excitation, common-mode rejection, and so on. </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  11. 11. Signal Conditioning <ul><li>One of the most common signal conditioning functions is amplification. </li></ul><ul><li>For maximum resolution, the voltage range of the input signals should be approximately equal to the maximum input range of the A/D converter. Amplification expands the range of the transducer signals so that they match the input range of the A/D converter. For example, a x10 amplifier maps transducer signals which range from 0 to 1 V into the range 0 to 10 V before they go into the A/D converter. </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  12. 12. Signal Conditioning <ul><li>Electrical signals are conditioned so they can be used by an analog input board. The following features may be available: </li></ul><ul><ul><li>Amplification </li></ul></ul><ul><ul><li>Isolation </li></ul></ul><ul><li>Filtering </li></ul><ul><li>Linearization </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  13. 13. Data Acquisition <ul><li>Data acquisition and control hardware generally performs one or more of the following functions: </li></ul><ul><ul><li>analog input, </li></ul></ul><ul><ul><li>analog output, </li></ul></ul><ul><ul><li>d igital input, </li></ul></ul><ul><ul><li>digital output and </li></ul></ul><ul><ul><li>counter/timer functions. </li></ul></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  14. 14. A/D Converter: Sampling Rate <ul><li>Determines how often conversions take place. </li></ul><ul><li>The higher the sampling rate, the better. </li></ul>Analog Input 4 Samples/cycle 8 Samples/cycle 16 Samples/cycle 06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  15. 15. A/D Converter: Sampling Rate <ul><li>Aliasing. </li></ul><ul><ul><li>Acquired signal gets distorted if sampling rate is too small. </li></ul></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  16. 16. A/D Converter: Throughput <ul><li>Effective rate of each individual channel is inversely proportional to the number of channels sampled. </li></ul><ul><li>Example: </li></ul><ul><ul><li>100 KHz maximum. </li></ul></ul><ul><ul><li>16 channels. </li></ul></ul><ul><li>100 KHz/16 = 6.25 KHz per channel. </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  17. 17. A/D Converter: Range <ul><li>Minimum and maximum voltage levels that the A/D converter can quantize </li></ul><ul><li>Ranges are selectable (either hardware or software) to accurately measure the signal </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  18. 18. A/D Converter: Resolution 06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |
  19. 19. <ul><li>Percobaan transformasi forier mengunakan Matlab </li></ul>06/02/11 © 2010 Universitas Negeri Jakarta | www.unj.ac.id |

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