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SMJ 4222 Instrumentation (02 & 07) Dr Intan Zaurah Mat Darus
SMJ 4222 Instrumentation (02 & 07)Dr Intan Zaurah Mat DarusDr Intan Zaurah Mat Darus
Lecture 1
Introduction to measurement and instrumentation
What is measurement?
Measurement Standards and Measurement Standards and UnitsUnits
Measuring system are composed of different elements and condition therefore it needs norms and standards
3 unit systems widely used-International System (SI), CGS System, English System
Basic units - length, time, mass, temperatureDerived units –area, volume, acceleration, force
International System of Units (SI)International System of Units (SI)
The SI is founded on seven SI base units for seven base quantities assumed to be mutually independent, as given in Table 1.
SI base unit
Base quantity Name Symbol
length meter m
mass kilogram kg
time second s
electric current ampere A
thermodynamic temperature kelvin K
amount of substance mole mol
luminous intensity candela cd
Derived Units- defined in terms of the seven base quantities via a system of quantity equations. Examples are:
SI base unit
Name Derived units Symbol
area square meter m2
volume cubic meter m3
velocity meter per second m/s
accelerationMeter per second squared
m/s-2
force m·kg·s-2 N
pressure m-1·kg·s-2 Pa
work m2·kg·s-2 Joule
What is instrumentation?
Automotive Sensors
Oxygen Sensor
Airflow Sensor
Water Temperature
Oil Pressure
Accelerometer
CO Sensor
The need for measurement and instrumentation
In industrial application, it is important for:
1) monitoring and control of a process
2) improving the quality of the product and efficiency of production
3) Safety purposes
Laser Sensor
Laser sensor
Typical Instrumentation System
• Transducer - converts the measured value into another useful value (a sensor)
• Signal conditioner- “conditions” the signal from the sensor
• A/D Converter - changes the signal into a digital format
• Computer - processes, displays, and records the signal
Transducer Signal conditioner
A/D Converter
Display
Sensor• Thermocouple
• Resistance thermometer
Thermocoupleinput output
temperature e.m.f
inputResistance thermometer
output
temperature Resistance change
Signal conditioner• Amplifier
• Wheatstone bridge
input Amplifier
Voltage change
Small e.m.f
Larger voltage
inputWheatstone bridge
output
Amplifier
Resistance change
Larger voltage change
Display• Scale
• Computer
input
current change
scaleoutput
movement of pointer
input
analog signal
DAS VDUdigital signal
output
readings
Temperature Control
The Control System sets the current supplied to the heating elements in the furnace to keep the material temperature at the desired (setpoint) value.
Desired Temperature
Control System
Furnace and
Material
Temperature Sensor
Water level system
h
Assignment
Identify the elements for the pressure measurement system i.e. : transducer, signal conditioner, display
POINTER
SCALE
