SENSOR / TRANSDUCER

Busran

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)