3. UNIT-I BASICS OF METROLOGY
Introduction to metrology-Need-
Element Work piece, Instruments-
Persons-Environment-Their effect on
precision and accuracy-Errors-Errors in
measurement-Types-Control-Types of
standards.
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4. GENERAL APPLICATIONS
• Design and drawing
• Production planning
• Manufacturing
• Assembly section
• Research and
development
• Prizing
• Packaging
• Marketing
• Surveying
• Banking
• Medical metrology
• Food factory's
• Oil industry’s
• Piping
• Textile industry's
• Environment
• Austhetic
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5. INTRODUCTION TO METROLOGY
• Science of measurement
• Ensuring uniformity of measurement
• Developing new methods of measurement
• Analyzing new methods
• Gauges design, manufacturing and testing
• Changing units in the form of standards
• Researching cases and industrial inspection
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6. NEED FOR METROLOGY
• To determine true dimensions
• To ensure public health and human safety
• To evaluate the performance of a system
• To study the basic laws of nature
• To check the limitations of theory in practical
situation
• To design and finding new data
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7. TYPES OF METROLOGY
• SCIENTIFIC METROLOGY (Organization and
development)
• INDUSTRIAL METROLOGY (used in a wide
variety of industries)
• LEGAL METROLOGY
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8. METHODS OF MEASUREMENT
• Direct comparison (length, mass. time)
Primary measurement
Secondary measurement ( single
conversion)
Tertiary measurement (more than one
conversion)
• Indirect comparison
• Comparative (using comparators)
mechanical, electrical, hydraulic, pneumatic
types
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9. METHODS OF MEASUREMENT
• Coincidence
• Fundamental
• Contact
• Transposition
• Complementary
• Deflection
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12. STANDARD
• Physical representation of unit of
measurement
• The term standard is used to denote
universally accepted specifications for devices.
• Components or processes which ensure
conformity and interchangeability throughout
a particular industry.
• A standard provides a reference for assigning a
numerical value to a measured quantity.
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13. TYPES OF STANDARD
• International standards (Internationally
accepted)
• Primary standards ( National Physical
Laboratory at New Delhi)
• Secondary standards(Basic reference
standard)
• Working standards(To check the components)
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14. UNITS
• M.K.S,CGS &S.I
• System International
Fundamental units-Length, Mass, Time,
Temperature, Electric current & Luminus
intensity.
Supplementary units-radian, steradian
Derived units-A,V,Density,v,a,F,P,W,p
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15. 1. Primary sensing element (receives energy
as input signal)
2. Variable conversion element (without
changing)
3. Variable manipulation element
(magnification)
4. Data transmission element
5. Data processing element (modify)
6. Data presentation element (monitoring)
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GENERALIZED MEASURING ELEMENT
SYSTEM
18. PRECISION AND ACCURACY
• Accuracy tends to true value
• Refers to how the measured value agrees with
the true value
• Precision tends to degree of exactness
• Device accuracy
• Procedural effects
• Environmental effects
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22. ERRORS
• Difference between the measured value and true
value
True absolute error:
It is the algebraic difference between the result
of measurement and the conventional true value
of the quantity measured.
Apparent absolute error:
If the series of measurement are made then the
algebraic difference between one of the results of
measurement and the arithmetical mean is
known as apparent absolute error.
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25. • CORRECTION-value which is added
algebraically to the result of measurement
a numerical value is multiplied with
uncorrected result
• CALIBRATION
process of determining and adjusting the
instruments accuracy to make sure its
accuracy is within the manufacture’s
speciation.
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