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SENSOR / TRANSDUCER
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• 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 Phenomenon
Stimulus
Acoustic
Biological & Chemical
Electric
Magnetic
Quantity
Wave (amplitude, phase, polarization), Spectrum, Wave
Velocity
Fluid Concentrations (Gas or Liquid)
Charge, Voltage, Current, Electric Field (amplitude,
phase,
polarization), Conductivity, Permittivity
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
Primary
Transduction
measurand
Isyarat
input
• Blok diagram sensor
Secondary
Transduction
Isyarat
output
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 isyaratisyarat yang lemah/kecil
Active Sensor
Primary
Transduction
measurand
Secondary
Transduction
Isyarat
output
Isyarat
input
Auxiliary Energy
Source
• Blok Diagram Active Sensor
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
L  L 0[1   (T - T0)]
Metal A
δ
• Application
– Thermostat (makes or
breaks electrical
connection with
deflection)
Metal B
Temperature Sensor
• Resistance temperature
device.
R  R 0[1   (T - T0)]
R  R0 e
1 1 

 T T0 
 
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
m
k
b
Vibrating Base
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
I
p
+
n
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
VH 
I (protons)
I B
n  q t
+ + + + + + + + + + + + + + +
x
x
x
x
x
x
x
x
x B x
x
x
x
x
x
x
x
x
- - - - - - - - - - - - - - -
+
VH
-
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)
Tugas Kelompok
• Browsing, Reading, Resuming and Writing
• Presentating of Paper
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)