Download - SENSOR / TRANSDUCER
SENSOR / TRANSDUCER
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Pre
• Apakah Sensor Itu??• Apakah Transduser itu?????• Berikan gambaran Implementasi
Sensor/Transduser
Definisi
• Sensor adalah piranti yang mentransform (mengubah) suatu nilai (isyarat/energi) fisik ke nilai fisik yang lain (Electric)
• Menghubungkan antara fisik nyata dan industri electric dan piranti elektronika
• Di dunia industri berguna untuk monitoring, controlling, dan proteksi
• Sering disebut juga dengan Transducer
Transducer
• Sensor adalah piranti yang mentransform (mengubah) suatu nilai (isyarat/energi) fisik ke nilai fisik yang lain.
• Piranti yang memberikan output (yang bisa dipakai) sebagai tanggapan terhadap (measurand) kondisi, kuantitas fisik masukan.
• Ada beberapa kategori measurand
Sensor
• Tidak terbatas pada pengukuran besaran fisik saja, tetapi juga pada kimia, dan biologi
Detectable PhenomenonStimulus Quantity
Acoustic Wave (amplitude, phase, polarization), Spectrum, Wave Velocity
Biological & Chemical Fluid Concentrations (Gas or Liquid)
Electric Charge, Voltage, Current, Electric Field (amplitude, phase,
polarization), Conductivity, Permittivity
Magnetic Magnetic Field (amplitude, phase, polarization), Flux, Permeability
Optical Refractive Index, Reflectivity, Absorption
Thermal Temperature, Flux, Specific Heat, Thermal Conductivity
Mechanical Position, Velocity, Acceleration, Force, Strain, Stress, Pressure, Torque
Sensor
• Ada 6 tipe isyarat• Mechanical, contoh: panjang, luas, mass flow, gaya, torque,
tekanan, kecepatan, percepatan, panjang gel acoustic, dll• Thermal, contoh: temperature, panas, entropy, heat flow• Electrical, contoh: tegangan, arus, muatan, resistance,
frekuensi, dll• Magnetic, contoh: intensitas medan, flux density, dll• Radiant, contoh: intensitas, panjang gelombang, polarisasi, dll• Chemical, contoh: komposisi, konsentrasi, pH, kecepatan
reaksi, dll
Physical Principles• Amperes’s Law
– A current carrying conductor in a magnetic field experiences a force (e.g. galvanometer)
• Curie-Weiss Law– There is a transition temperature at which ferromagnetic materials exhibit
paramagnetic behavior
• Faraday’s Law of Induction– A coil resist a change in magnetic field by generating an opposing
voltage/current (e.g. transformer)
• Photoconductive Effect– When light strikes certain semiconductor materials, the resistance of the
material decreases (e.g. photoresistor)
Choosing a Sensor
Sensor
• Sensor mengkonversi dari suatu isyarat input ke suatu isyarat ouput.
• Sensor bisa saja menggunakan satu atau lebih pengkonversian untuk menghasilkan suatu isyarat keluaran
Diskusi
• Apa perbedaan antara Sensor dan Transduser?
• Isyarat apa saja yang mampu dirubah oleh Sensor atau Transduser?
Sensor Block Diagram
• Blok diagram sensor
measurand Primary Transduction
Secondary Transduction
Isyarat input
Isyaratoutput
Passive Sensor
• Mengkonversi sifat-sifat/isyarat fisik atau kimia ke dalam isyarat yang lain tanpa bantuan sumber energi
• Contoh : termocouple• Termocouple menghasilkan tegangan output
sebanding dengan suhu pada sambungan termcouple tersebut
Active Sensor
• Mengkonversi sifat-sifat/isyarat fisik atau kimia ke dalam isyarat yang lain dengan bantuan sumber energi
• Merupakan pilihan utama untuk isyarat-isyarat yang lemah/kecil
Active Sensor
• Blok Diagram Active Sensor
measurand Primary Transduction
Secondary Transduction
Isyarat input
Isyaratoutput
Auxiliary Energy Source
Analog Output
• Active sensor di industri elektronika mempunyai standar isyarat listrik baik analog (berupa tegangan atau arus) maupun digital
Digital Output
• Computer Based atau Microprocessor
Temperature Sensor
• Temperature sensors appear in building, chemical process plants, engines, appliances, computers, and many other devices that require temperature monitoring
• Many physical phenomena depend on temperature, so we can often measure temperature indirectly by measuring pressure, volume, electrical resistance, and strain
Temperature Sensor
• Bimetallic Strip
• Application– Thermostat (makes or
breaks electrical connection with deflection)
Metal A
Metal B
δ)]T-(T1[ 00 LL
Temperature Sensor
• Resistance temperature device.
0
11
0
00 )]T-(T1[
TTeRR
RR
Accelerometer• Accelerometers are used to
measure along one axis and is insensitive to orthogonal directions
• Applications– Vibrations, blasts, impacts, shock
waves– Air bags, washing machines,
heart monitors, car alarms
• Mathematical Description is beyond the scope of this presentation. See me during lunch if interested
Vibrating Base
m
k b
Position Sensor
Light Sensor
• Light sensors are used in cameras, infrared detectors, and ambient lighting applications
• Sensor is composed of photoconductor such as a photoresistor, photodiode, or phototransistor
p n
I
+ V -
Magnetic Field Sensor
• Magnetic Field sensors are used for power steering, security, and current measurements on transmission lines
• Hall voltage is proportional to magnetic field x x x x x x
x x x x x xx x x x x x
+ + + + + + + + + + + + + + +
- - - - - - - - - - - - - - -
I (protons) +VH
-B
tqnBIVH
Ultrasonic Sensor
• Ultrasonic sensors are used for position measurements
• Sound waves emitted are in the range of 2-13 MHz
• Sound Navigation And Ranging (SONAR)
• Radio Dection And Ranging (RADAR) – ELECTROMAGNETIC WAVES !!
15° - 20°
Photogate• Photogates are used in
counting applications (e.g. finding period of period motion)
• Infrared transmitter and receiver at opposite ends of the sensor
• Time at which light is broken is recorded
CO2 Gas Sensor
• CO2 sensor measures gaseous CO2 levels in an environment
• Measures CO2 levels in the range of 0-5000 ppm
• Monitors how much infrared radiation is absorbed by CO2 molecules
Infrared Source IR Detector
Kesimpulan dan Diskusi
Tugas Kelompok
• Implementasi Sensor dalam Dunia Industri– Sensor Cahaya, Sensor Berat, Sensor Suhu,
Sensor Suara, Sensor Jarak, Sensor Regangan• Makalah :
– Teori Pengantar Sensor– Rangkaian Elektronika Sensor– Prinsip Kerja– Algoritma Program dalam Implementasi
(Opsional)
• Browsing, Reading, Resuming and Writing• Presentating of Paper
Tugas Kelompok
HART
• Highway Addressable Remote Transducer• Salah satu protocol komunikasi untuk
sensor• Untuk remote data acquisition dan kontrol• Standart 4 to 20 mA, Teknik FSK• Digital format : 1200 & 2200 (logic 1 & 0)