Introduction to Mechanical Measurements and Classification of Instruments

1. Unit No. 1
Mechanical Measurement
By:
Manish V Sharma
Asst. Prof.

2. Introduction
• The measurement of a given quantity is essentially an act or
result of comparison between a quantity, whose magnitude is
unknown with a similar quantity whose magnitude is known,
the latter being called standard.

3. • Essential elements of scientific instruments
• A Detector
• An intermediate transfer devices
• An indicator, recorder or a storage device

4. Mechanical Instruments
• Very reliable for static and stable condition
• Unable to respond rapidly to measurements
of dynamic and transient condition
• Due to rigid, heavy and bulky parts have large
mass hence cannot faithfully follow the rapid
change
• Are potential source of noise pollution

5. Electrical Instruments
• Electrical instrument are more rapid than
mechanical type
• An electrical system normally depends upon a
mechanical meter movement as indicating
device

6. Electronic Instruments
• Today’s requirement of measuring instrument
is very fast response
• Electronic instrument uses semiconductor
devices
• Since in electronic devices, the only
movement involved is that of electrons the
response time is very small

7. Functions of Instruments and
Measurement Systems
• Indicating Function:-
• Recording Function:-
• Controlling Function:-

8. Types of Instruments
• Mode of measurement
• Primary Instrument
• Secondary Instrument
• Tertiary Instrument
• Nature of Contact
• Contact type
• Non Contact type

9. Types of Instruments continued
• Signal Being Processed
• Analog Measuring Instrument
• Digital Measuring Instrument
• Condition of Pointer
• Null Type
• Deflection type
• Power Source Required
• Self sufficient Instrument (Active )
• Power operated instrument (Passive)

10. Functional Elements of an
Instrumentation system
• Primary Sensing Element
• Variable Conversion Element
• Variable Manipulation Element
• Data Transmission Element
• Data Presentation Element

11. Functional Elements of an
Instrumentation systemUnknown
Primary
Sensing
Element
Variable
Conversion
Element
Variable
Manipulation
Element
Data
Transmission
Element
Data
Presentation
Element
Output

12. Example