# Instrumentasi Sistem Pengaturan - Website - 01...Instrumentasi Sistem Pengaturan - 01 1 Instrumentasi Sistem Pengaturan Pengantar Sistem Instrumentasi. Ir. Jos. Pramudijanto, M.Eng

• View
244

9

Embed Size (px)

### Text of Instrumentasi Sistem Pengaturan - Website - 01...Instrumentasi Sistem Pengaturan - 01 1...

• Instrumentasi Sistem Pengaturan - 01 1

Instrumentasi Sistem Pengaturan

Pengantar Sistem Instrumentasi

Ir. Jos Pramudijanto, M.Eng.Jurusan Teknik Elektro FTI ITS

Telp. 5947302 Fax.5931237Email: pramudijanto@gmail.com

• Instrumentasi Sistem Pengaturan - 01 2

Objektif

Mengetahui konfigurasi sistem instrumentasi; Perbedaan dari sensor dan tranduser; Mengetahui pentingnya manfaat pengukuran; Akurasi dari sensor;

• Instrumentasi Sistem Pengaturan - 01 3

A Instrumentation systems includes all the components necessary for producing a measurement.

Instrumentation Systems

• Instrumentasi Sistem Pengaturan - 01 4

Bicycle Speedometer

Sensor: A Magnet attached to one of the spokesTransducer: The Hall Effect device that produces an electrical pulse as the magnet passesSignal Conditioning: A circuit compares the pulses to a timer and determines the period. A correlation based on the measured period and wheel diameter is used to determine velocity.Output Stage: A digital signal is sent to the LCD displays and the velocity appears on the screen

• Instrumentasi Sistem Pengaturan - 01 5

Measurement: Comparison between a standard and what we want to measure (the measurand).What is the standard?

Width of a mans thumb =1 inchLength of a mans foot = 1 footLength of a mans belt = 1 yard

There is a need for an unchanging standard for physical parameters

length(m), time(s), mass(kg), temperature(K), etc.

Other parameters can be defined in terms of these standard parameters (velocity = length/time)Oversight of standards and definitions (IEEE)

What is a Measurement ?

• Instrumentasi Sistem Pengaturan - 01 6

Sensor converts some physical quantity into an electrical quantity

Transducer converts one form of energy into another

What is a Sensor and Transducer ?

• Instrumentasi Sistem Pengaturan - 01 7

Sensors and Actuators

Transducers:a sensor is an electronic transducer that converts a physical quantity into an electrical signal,an actuator is an electronic transducer that converts electrical energy into a physical quantity.They are essential to digital control systems.

• Instrumentasi Sistem Pengaturan - 01 8

TradeGetting what you pay forGetting parts that fit

DesignDesign parameters are based on experimental measurement (ex. max. temperature = 140oC)Analysis based on measurement (Testing: Does the part fail under max load at T = 140oC?)

ControlSafety (stall sensors on an aircraft wing measure lift)Economy (fuel system controls on an automobile)

Why is Measurement so Important ?

• Instrumentasi Sistem Pengaturan - 01 9

Strain gauge

Strain-gauge Measurement System

• Instrumentasi Sistem Pengaturan - 01 10

Oxygen Sensor

Airflow Sensor

Water Temperature

Oil Pressure

Accelerometer

CO Sensor

Automotive Measurement System

• Instrumentasi Sistem Pengaturan - 01 11

Ultrasound Transducer

Biomedical Measurement System

• Instrumentasi Sistem Pengaturan - 01 12

Direct comparisonMeasure length with a rulerMeasure mass with a balanceMeasure pressure with a deadweight pressure gage

Indirect comparisonUse of a measuring systemRequires calibrationMeasure temperature with a thermometerMeasure velocity with a bicycle speedometer

How Do we Measure with Sensor ?

• Instrumentasi Sistem Pengaturan - 01 13

There is always some uncertainty in measurementsUncertainty: A likely bound on the error

The application prescribes the required accuracySignificant consequencesCore temperature of a nuclear reactor vs. outdoor temperatureFunctionalityMeasurement of lens curvature on eyeglasses vs. curvature of a wide-angle mirror

Error Definition: Difference between the actual value and the measured valuePrecision errorBias error

How Accurate is the Sensor ?

• Instrumentasi Sistem Pengaturan - 01 14

Precision Error

RandomCauses measurement to be randomly above or below the the average value

Estimated by statistical methodsEstimation based on standard deviation

Example: Darts

• Instrumentasi Sistem Pengaturan - 01 15

Bias Error

SystematicConstant fractional or total error

Can not be estimated by statistical methodsEstimation based on an understanding of sources of error

Example: Darts

Instrumentasi Sistem PengaturanSlide Number 2Instrumentation Systems Bicycle SpeedometerSlide Number 5Slide Number 6Sensors and ActuatorsSlide Number 8Strain-gauge Measurement SystemAutomotive Measurement SystemBiomedical Measurement SystemHow Do we Measure with Sensor ?How Accurate is the Sensor ?Precision ErrorBias Error

Documents
Documents
Documents
Documents
Documents
Documents
Documents
Documents
Documents
Documents
Documents
Documents