SlideShare a Scribd company logo
1 of 31
kongunadu college of Engg & Tech
Prepared By
Tamilnesan P
KNCET
Characteristics of
Instruments
 There are Two types of
characteristics of instruments:-
 1.Static characteristics of
instruments
 2.Dynamic Characteristics of
instruments.
KNCET
1.Static Characteristics
 The static characteristics
instrument are required
of an
to be
considered for the instruments which
measure unvarying process
conditions.
 The static characteristics are defined
for the instruments which measure
quantities which do not vary with
time.
KNCET
are :-
1. Accuracy
2. Sensitivity
3. Reproducibility
4. Drift
5. Static error
6. Dead zone
7. Precision
8. Threshold
9. Linearity
10. Stability
11. Range or Span
12. Bais
13. Tolerance
14. Hysteresis
The main static characteristics
KNCET
1. Accuracy
It is the degree of closeness with which an
instrument reading approaches the true value of
the quantity being measured.
The accuracy of a measurement indicates the
nearness to the actual/true value of the quantity.
KNCET
2.Sensitivity
 Sensitivity is the ratio of change in output of
an instrument to the change in input.
 The manufactures specify sensitivity as the
ratio of magnitude of the measured quantity
to the magnitude of the response.This ratio is
called as Inverse sensitivity or deflection
factor.
KNCET
KNCET
Sensitivity Meter:-
KNCET
3.Reproducibility
Reproducibility is defined as the degree of
closeness by which a given value can be
repeatedly measured.
The reproducibility is specified for a period of
time.
Perfect reproducibility signifies that the given
readings that are taken for an input, do not vary
with time..
KNCET
KNCET
4.Drift
The drift is defined as the gradual shift in the
indication over a period of time where in the
input variable does not change.
Drift may be caused because of environment
factors like stray electric fields, stray magnetic
fields, thermal e.m.fs, changes in temperature,
mechanical vibrations etc.
 Drift is classified into three categories:
1. Zero drift
2. Span drift or sensitivity drift
3. Zonal drift KNCET
5. Static error
It is the deviation from the true value of the
measured variable.
It involves the comparison of an unknown
quantity with an accepted standard quantity.
The degree to which an instrument approaches
to its excepted value is expressed terms of error
of measurement.
KNCET
6.Dead zone
It is the largest changes of input quantity for
which there is no output.
For e.g. the input that is applied to an
instrument may not be sufficient to overcome
friction. It will only respond when it overcomes
the friction forces.
KNCET
7.Precision
It is a measure of the reproducibility of the
measurement that is given a fixed value of
variable.
Precision is a measure of the degree to which
successive measurements differ from each
other.
For example consider an instrument on which
readings can be taken upto 1∕100th of unit.
The instrument has zero adjustment error. So,
when we take a readings, the instrument is
highly precise. However as the instrument has
a zero adjustment error the readings obtained
are precise, but they are not accurate.
Thus, when a set of readings show precision,
the results agree among themselves. However, it
is not essential that the results are accurate.KNCET
Precision Measuring instruments
KNCET
8.Threshsold
Threshold is the smallest measurable input,
below which no output change can be identified.
While specifying threshold, manufactures give
the first detectable output change.
KNCET
9.Linearity
Linearity is defined as the ability of an
instrument to reproduce its input linearly.
Linearity is simply a measure of the maximum
deviation of the calibration points from the ideal
straight line.
Linearity is defined as,
linearity=Maximum deviation of o/p from
idealized straight line ∕ Actual readings
KNCET
10.Stability
The ability of an instrument to retain its
performance throughout its specified storage life
and operating life is called as Stability.
Stability measurement instruments:-
KNCET
11.Range or Span
The minimum and maximum values of a
quantity for which an instrument is designed to
measure is called its range or span. Sometimes
the accuracy is specified interms of range or
span of an instrument.
KNCET
12.Bais
The constant error which exists over the full
range of measurement of an instrument is called
bias. Such a bais can be completely eliminated
by calibration. The zero error is an example of
bais which can be removed by calibration.
KNCET
13.Tolerance
It is the maximum allowable
specified in terms of certain
error that is
value while
measurement, it is called as tolerance.
It specifies the maximum allowable deviation of
a manufactured device from a mentioned value.
KNCET
14.Hysteresis
Hysteresis is a phenomenon which depicts
different output effects while loading and
unloading.
Hysteresis takes place due to the fact that all
the energy put into the stressed parts when
loading is not recoverable while unloading.
When the input of an instrument is varied from
zero to its full scale and then if the input is
decreased from its full scale value to zero, the
output varies. The output at the particular input
while increasing and decreasing varies because
of internal friction or hysteric damping.
KNCET
KNCET
2.Dynamic Characteristics
Instruments rarely respond to the
instantaneous changes in the measured
variables.Their response is slow or sluggish due
to mass, thermal capacitance, electrical
capacitance, inductance etc. sometimes, even
the instrument has to wait for some time till, the
response occurs.
These type of instruments are normally used
for the measurement of quantities that fluctuate
with time.
The behaviour of such a system, where as the
input varies from instant to instant, the output
also varies from instant to instant is called as
dynamic response of the system.
Hence, the dynamic behaviour of the system is
also important as the static behaviour.
KNCET
The dynamic inputs are of two types:
1. Transient
2. Steady state periodic.
 Transient response is defined as that part of
the response which goes to zero as the time
becomes large.
 The steady state response is the response
that has a definite periodic cycle.
KNCET
The variations in the input, that are used
practically to achieve dynamic behaviour are:
I. Step input:-The input is subjected to a finite
and instantaneous change. E.g.: closing of
switch.
II. Ramp input:- The input linearly changes with
respect to time.
III. Parabolic
square of
input:- The input varies to the
time. This represents constant
input:- The input
acceleration.
IV. Sinusoidal
accordance with a sinusoidal
changes in
function of
constant amplitude.
KNCET
The dynamic characteristics of a measurement
system are:
1) Speed of response
2) Fidelity
3) Lag
4) Dynamic error
KNCET
1) Speed of Response
instrument, responds to the changes in
It is defined as the rapidity with which an
the
measured quantity.
It shows how active and fast the system is.
Speed measuring instruments:-
KNCET
2) Fidelity
It is defined as the degree to which a
measurement system is capable of faithfully
reproducing the changes in input, without any
dynamic error.
KNCET
3)Lag
Every system requires its own time to respond to
the changes in input. This time is called as lag.
It is defined as the retardation or delay, in the
response of a system to the changes in the input.
The lags are of two types:
1. Retardation lag:
As soon as there is a changes in the
measured quantity, the measurement system
begins to respond.
2. Time delay:
The response of the measurement system
starts after a dead time, once the input is
applied.They cause dynamic error.
KNCET
4)Dynamic error
It is the difference between the true value of
the quantity that is to be measured, changing
with time and the measured value, if no static
error is assumed.
KNCET

More Related Content

What's hot

L7 measurement system
L7 measurement systemL7 measurement system
L7 measurement systemtaruian
 
CHARACTERISTICS OF AN INSTRUMENT
CHARACTERISTICS OF AN INSTRUMENT CHARACTERISTICS OF AN INSTRUMENT
CHARACTERISTICS OF AN INSTRUMENT Kunj Thummar
 
Sensor and transducers lect 1
Sensor and transducers lect 1Sensor and transducers lect 1
Sensor and transducers lect 1prashant tripathi
 
Displacement measurement
Displacement measurementDisplacement measurement
Displacement measurementwasim shah
 
Lecture1 measurement & intrumentation
Lecture1 measurement & intrumentationLecture1 measurement & intrumentation
Lecture1 measurement & intrumentationasmawi78
 
Vibration measuring instrument - Vibrometer
Vibration measuring instrument - VibrometerVibration measuring instrument - Vibrometer
Vibration measuring instrument - VibrometerVenkatesh Tadivalasa
 
Static and Dynamic characteristics of Measuring Instrument
Static and Dynamic characteristics of Measuring Instrument Static and Dynamic characteristics of Measuring Instrument
Static and Dynamic characteristics of Measuring Instrument Archana Vijayakumar
 
Introduction to Mechanical Measurement
Introduction to Mechanical MeasurementIntroduction to Mechanical Measurement
Introduction to Mechanical MeasurementNaman Dave
 
Measuring instruments
Measuring instrumentsMeasuring instruments
Measuring instrumentsSayyed Raza
 
Vibration measurement
Vibration  measurementVibration  measurement
Vibration measurementssusera970cc
 
Instrumentation & Measurement: Types and Static Characteristics of Instruments
Instrumentation & Measurement: Types and Static Characteristics of InstrumentsInstrumentation & Measurement: Types and Static Characteristics of Instruments
Instrumentation & Measurement: Types and Static Characteristics of InstrumentsMuhammad Junaid Asif
 
Static characteristics - Mechanical Measurements
Static characteristics - Mechanical MeasurementsStatic characteristics - Mechanical Measurements
Static characteristics - Mechanical MeasurementsAmeya Nijasure
 
Subject: Mechanical Engineering Measurement. Ch. no. 2. displacement, force ...
Subject: Mechanical Engineering Measurement.  Ch. no. 2. displacement, force ...Subject: Mechanical Engineering Measurement.  Ch. no. 2. displacement, force ...
Subject: Mechanical Engineering Measurement. Ch. no. 2. displacement, force ...Amol Kokare
 

What's hot (20)

Thermistor
ThermistorThermistor
Thermistor
 
Tachometer
TachometerTachometer
Tachometer
 
L7 measurement system
L7 measurement systemL7 measurement system
L7 measurement system
 
Displacement measurement
Displacement measurementDisplacement measurement
Displacement measurement
 
CHARACTERISTICS OF AN INSTRUMENT
CHARACTERISTICS OF AN INSTRUMENT CHARACTERISTICS OF AN INSTRUMENT
CHARACTERISTICS OF AN INSTRUMENT
 
Sensor and transducers lect 1
Sensor and transducers lect 1Sensor and transducers lect 1
Sensor and transducers lect 1
 
Displacement measurement
Displacement measurementDisplacement measurement
Displacement measurement
 
Lecture1 measurement & intrumentation
Lecture1 measurement & intrumentationLecture1 measurement & intrumentation
Lecture1 measurement & intrumentation
 
Vibration measuring instrument - Vibrometer
Vibration measuring instrument - VibrometerVibration measuring instrument - Vibrometer
Vibration measuring instrument - Vibrometer
 
Static and Dynamic characteristics of Measuring Instrument
Static and Dynamic characteristics of Measuring Instrument Static and Dynamic characteristics of Measuring Instrument
Static and Dynamic characteristics of Measuring Instrument
 
Introduction to Mechanical Measurement
Introduction to Mechanical MeasurementIntroduction to Mechanical Measurement
Introduction to Mechanical Measurement
 
Measuring instruments
Measuring instrumentsMeasuring instruments
Measuring instruments
 
Mechanical measurement
Mechanical measurementMechanical measurement
Mechanical measurement
 
Vibration measurement
Vibration  measurementVibration  measurement
Vibration measurement
 
Force measurement
Force measurementForce measurement
Force measurement
 
Capacitive Type Transducer
Capacitive Type Transducer Capacitive Type Transducer
Capacitive Type Transducer
 
25633083 sensors-and-transducers
25633083 sensors-and-transducers25633083 sensors-and-transducers
25633083 sensors-and-transducers
 
Instrumentation & Measurement: Types and Static Characteristics of Instruments
Instrumentation & Measurement: Types and Static Characteristics of InstrumentsInstrumentation & Measurement: Types and Static Characteristics of Instruments
Instrumentation & Measurement: Types and Static Characteristics of Instruments
 
Static characteristics - Mechanical Measurements
Static characteristics - Mechanical MeasurementsStatic characteristics - Mechanical Measurements
Static characteristics - Mechanical Measurements
 
Subject: Mechanical Engineering Measurement. Ch. no. 2. displacement, force ...
Subject: Mechanical Engineering Measurement.  Ch. no. 2. displacement, force ...Subject: Mechanical Engineering Measurement.  Ch. no. 2. displacement, force ...
Subject: Mechanical Engineering Measurement. Ch. no. 2. displacement, force ...
 

Similar to Characteristics of Instruments for Measurement

DEE-305 Characteristics of instrument .pdf
DEE-305 Characteristics of instrument .pdfDEE-305 Characteristics of instrument .pdf
DEE-305 Characteristics of instrument .pdfTHEWITCHERGAMING
 
SENSORS_AND_INST.UNIT_1_REG_17__Presentation.ppt
SENSORS_AND_INST.UNIT_1_REG_17__Presentation.pptSENSORS_AND_INST.UNIT_1_REG_17__Presentation.ppt
SENSORS_AND_INST.UNIT_1_REG_17__Presentation.pptSenthilKumarP45
 
Introduction to measurement By Gadkar Sagar P.
Introduction to measurement By Gadkar Sagar P.Introduction to measurement By Gadkar Sagar P.
Introduction to measurement By Gadkar Sagar P.SagarGadkar4
 
Fundamentals on Measurement and uncertainty
Fundamentals on Measurement  and  uncertaintyFundamentals on Measurement  and  uncertainty
Fundamentals on Measurement and uncertaintyBerkefede
 
Introduction about Instrumentation.ppt
Introduction about Instrumentation.pptIntroduction about Instrumentation.ppt
Introduction about Instrumentation.pptMuhammadShoaibRabban2
 
Mechatronics study material-Question Bank.pdf
Mechatronics study material-Question Bank.pdfMechatronics study material-Question Bank.pdf
Mechatronics study material-Question Bank.pdfRajaSekaran923497
 
Characteristics of Instruments.pptx
Characteristics of Instruments.pptxCharacteristics of Instruments.pptx
Characteristics of Instruments.pptxAdnanZafar83
 
Mechanical measurement 1
Mechanical measurement 1Mechanical measurement 1
Mechanical measurement 1Sangram Petkar
 
Characteristics of Measuring instruments
Characteristics of Measuring instrumentsCharacteristics of Measuring instruments
Characteristics of Measuring instrumentsGAURAVBHARDWAJ160
 
Static and dynamic_characteristics_of_measurement_system
Static and dynamic_characteristics_of_measurement_systemStatic and dynamic_characteristics_of_measurement_system
Static and dynamic_characteristics_of_measurement_systemPrabhaMaheswariM
 
Introduction to Measurement Transducers.ppt
Introduction to Measurement Transducers.pptIntroduction to Measurement Transducers.ppt
Introduction to Measurement Transducers.pptPratheepVGMTS
 
chapter one.pptx
chapter one.pptxchapter one.pptx
chapter one.pptxgetacew1
 
Lecture Notes: EEEC6430312 Measurements And Instrumentation - Instrument Typ...
Lecture Notes:  EEEC6430312 Measurements And Instrumentation - Instrument Typ...Lecture Notes:  EEEC6430312 Measurements And Instrumentation - Instrument Typ...
Lecture Notes: EEEC6430312 Measurements And Instrumentation - Instrument Typ...AIMST University
 
Measurements kkkkkkkkkkkkkkkkkkkch(1)1.pptx
Measurements kkkkkkkkkkkkkkkkkkkch(1)1.pptxMeasurements kkkkkkkkkkkkkkkkkkkch(1)1.pptx
Measurements kkkkkkkkkkkkkkkkkkkch(1)1.pptxAhmedWail2
 
2nd ppt of agricultural instrumentation.
2nd ppt of agricultural instrumentation.2nd ppt of agricultural instrumentation.
2nd ppt of agricultural instrumentation.lauralasun1865
 

Similar to Characteristics of Instruments for Measurement (20)

DEE-305 Characteristics of instrument .pdf
DEE-305 Characteristics of instrument .pdfDEE-305 Characteristics of instrument .pdf
DEE-305 Characteristics of instrument .pdf
 
PPT2.pdf
PPT2.pdfPPT2.pdf
PPT2.pdf
 
SENSORS_AND_INST.UNIT_1_REG_17__Presentation.ppt
SENSORS_AND_INST.UNIT_1_REG_17__Presentation.pptSENSORS_AND_INST.UNIT_1_REG_17__Presentation.ppt
SENSORS_AND_INST.UNIT_1_REG_17__Presentation.ppt
 
Introduction to measurement By Gadkar Sagar P.
Introduction to measurement By Gadkar Sagar P.Introduction to measurement By Gadkar Sagar P.
Introduction to measurement By Gadkar Sagar P.
 
Fundamentals on Measurement and uncertainty
Fundamentals on Measurement  and  uncertaintyFundamentals on Measurement  and  uncertainty
Fundamentals on Measurement and uncertainty
 
Unit I
Unit IUnit I
Unit I
 
Introduction about Instrumentation.ppt
Introduction about Instrumentation.pptIntroduction about Instrumentation.ppt
Introduction about Instrumentation.ppt
 
Mechatronics study material-Question Bank.pdf
Mechatronics study material-Question Bank.pdfMechatronics study material-Question Bank.pdf
Mechatronics study material-Question Bank.pdf
 
Chapter 1-notes
Chapter 1-notesChapter 1-notes
Chapter 1-notes
 
Characteristics of Instruments.pptx
Characteristics of Instruments.pptxCharacteristics of Instruments.pptx
Characteristics of Instruments.pptx
 
Mechanical measurement 1
Mechanical measurement 1Mechanical measurement 1
Mechanical measurement 1
 
Characteristics of Measuring instruments
Characteristics of Measuring instrumentsCharacteristics of Measuring instruments
Characteristics of Measuring instruments
 
Static and dynamic_characteristics_of_measurement_system
Static and dynamic_characteristics_of_measurement_systemStatic and dynamic_characteristics_of_measurement_system
Static and dynamic_characteristics_of_measurement_system
 
Introduction to Measurement Transducers.ppt
Introduction to Measurement Transducers.pptIntroduction to Measurement Transducers.ppt
Introduction to Measurement Transducers.ppt
 
Emi unit 1 ppt
Emi unit 1 pptEmi unit 1 ppt
Emi unit 1 ppt
 
chapter one.pptx
chapter one.pptxchapter one.pptx
chapter one.pptx
 
Lecture Notes: EEEC6430312 Measurements And Instrumentation - Instrument Typ...
Lecture Notes:  EEEC6430312 Measurements And Instrumentation - Instrument Typ...Lecture Notes:  EEEC6430312 Measurements And Instrumentation - Instrument Typ...
Lecture Notes: EEEC6430312 Measurements And Instrumentation - Instrument Typ...
 
Measurements kkkkkkkkkkkkkkkkkkkch(1)1.pptx
Measurements kkkkkkkkkkkkkkkkkkkch(1)1.pptxMeasurements kkkkkkkkkkkkkkkkkkkch(1)1.pptx
Measurements kkkkkkkkkkkkkkkkkkkch(1)1.pptx
 
2nd ppt of agricultural instrumentation.
2nd ppt of agricultural instrumentation.2nd ppt of agricultural instrumentation.
2nd ppt of agricultural instrumentation.
 
MI Mod 1.ppt
MI Mod 1.pptMI Mod 1.ppt
MI Mod 1.ppt
 

More from tamilnesaner (15)

BEEME UNIT V.ppt
BEEME UNIT V.pptBEEME UNIT V.ppt
BEEME UNIT V.ppt
 
Unit 4
Unit 4Unit 4
Unit 4
 
Unit 5
Unit 5Unit 5
Unit 5
 
Unit 3 mpmc
Unit 3 mpmcUnit 3 mpmc
Unit 3 mpmc
 
Unit 2 mpmc
Unit 2 mpmcUnit 2 mpmc
Unit 2 mpmc
 
Unit 1 MPMC
Unit 1 MPMCUnit 1 MPMC
Unit 1 MPMC
 
Smart meter
Smart meterSmart meter
Smart meter
 
Lcr meter
Lcr meterLcr meter
Lcr meter
 
Tachometer and clamp meter
Tachometer and clamp meterTachometer and clamp meter
Tachometer and clamp meter
 
Unit 5
Unit 5Unit 5
Unit 5
 
Unit 4
Unit 4Unit 4
Unit 4
 
Unit 3
Unit 3Unit 3
Unit 3
 
Unit 2
Unit 2Unit 2
Unit 2
 
Unit 1
Unit 1Unit 1
Unit 1
 
Three phase voltage source inverter
Three phase voltage source inverterThree phase voltage source inverter
Three phase voltage source inverter
 

Recently uploaded

System Simulation and Modelling with types and Event Scheduling
System Simulation and Modelling with types and Event SchedulingSystem Simulation and Modelling with types and Event Scheduling
System Simulation and Modelling with types and Event SchedulingBootNeck1
 
Katarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School CourseKatarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School Coursebim.edu.pl
 
Mine Environment II Lab_MI10448MI__________.pptx
Mine Environment II Lab_MI10448MI__________.pptxMine Environment II Lab_MI10448MI__________.pptx
Mine Environment II Lab_MI10448MI__________.pptxRomil Mishra
 
Internet of things -Arshdeep Bahga .pptx
Internet of things -Arshdeep Bahga .pptxInternet of things -Arshdeep Bahga .pptx
Internet of things -Arshdeep Bahga .pptxVelmuruganTECE
 
Crystal Structure analysis and detailed information pptx
Crystal Structure analysis and detailed information pptxCrystal Structure analysis and detailed information pptx
Crystal Structure analysis and detailed information pptxachiever3003
 
Work Experience-Dalton Park.pptxfvvvvvvv
Work Experience-Dalton Park.pptxfvvvvvvvWork Experience-Dalton Park.pptxfvvvvvvv
Work Experience-Dalton Park.pptxfvvvvvvvLewisJB
 
Arduino_CSE ece ppt for working and principal of arduino.ppt
Arduino_CSE ece ppt for working and principal of arduino.pptArduino_CSE ece ppt for working and principal of arduino.ppt
Arduino_CSE ece ppt for working and principal of arduino.pptSAURABHKUMAR892774
 
multiple access in wireless communication
multiple access in wireless communicationmultiple access in wireless communication
multiple access in wireless communicationpanditadesh123
 
Ch10-Global Supply Chain - Cadena de Suministro.pdf
Ch10-Global Supply Chain - Cadena de Suministro.pdfCh10-Global Supply Chain - Cadena de Suministro.pdf
Ch10-Global Supply Chain - Cadena de Suministro.pdfChristianCDAM
 
"Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ..."Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ...Erbil Polytechnic University
 
Autonomous emergency braking system (aeb) ppt.ppt
Autonomous emergency braking system (aeb) ppt.pptAutonomous emergency braking system (aeb) ppt.ppt
Autonomous emergency braking system (aeb) ppt.pptbibisarnayak0
 
Immutable Image-Based Operating Systems - EW2024.pdf
Immutable Image-Based Operating Systems - EW2024.pdfImmutable Image-Based Operating Systems - EW2024.pdf
Immutable Image-Based Operating Systems - EW2024.pdfDrew Moseley
 
Earthing details of Electrical Substation
Earthing details of Electrical SubstationEarthing details of Electrical Substation
Earthing details of Electrical Substationstephanwindworld
 
home automation using Arduino by Aditya Prasad
home automation using Arduino by Aditya Prasadhome automation using Arduino by Aditya Prasad
home automation using Arduino by Aditya Prasadaditya806802
 
National Level Hackathon Participation Certificate.pdf
National Level Hackathon Participation Certificate.pdfNational Level Hackathon Participation Certificate.pdf
National Level Hackathon Participation Certificate.pdfRajuKanojiya4
 
Energy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptxEnergy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptxsiddharthjain2303
 
Main Memory Management in Operating System
Main Memory Management in Operating SystemMain Memory Management in Operating System
Main Memory Management in Operating SystemRashmi Bhat
 
DM Pillar Training Manual.ppt will be useful in deploying TPM in project
DM Pillar Training Manual.ppt will be useful in deploying TPM in projectDM Pillar Training Manual.ppt will be useful in deploying TPM in project
DM Pillar Training Manual.ppt will be useful in deploying TPM in projectssuserb6619e
 

Recently uploaded (20)

System Simulation and Modelling with types and Event Scheduling
System Simulation and Modelling with types and Event SchedulingSystem Simulation and Modelling with types and Event Scheduling
System Simulation and Modelling with types and Event Scheduling
 
Katarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School CourseKatarzyna Lipka-Sidor - BIM School Course
Katarzyna Lipka-Sidor - BIM School Course
 
Mine Environment II Lab_MI10448MI__________.pptx
Mine Environment II Lab_MI10448MI__________.pptxMine Environment II Lab_MI10448MI__________.pptx
Mine Environment II Lab_MI10448MI__________.pptx
 
Design and analysis of solar grass cutter.pdf
Design and analysis of solar grass cutter.pdfDesign and analysis of solar grass cutter.pdf
Design and analysis of solar grass cutter.pdf
 
Internet of things -Arshdeep Bahga .pptx
Internet of things -Arshdeep Bahga .pptxInternet of things -Arshdeep Bahga .pptx
Internet of things -Arshdeep Bahga .pptx
 
Crystal Structure analysis and detailed information pptx
Crystal Structure analysis and detailed information pptxCrystal Structure analysis and detailed information pptx
Crystal Structure analysis and detailed information pptx
 
Work Experience-Dalton Park.pptxfvvvvvvv
Work Experience-Dalton Park.pptxfvvvvvvvWork Experience-Dalton Park.pptxfvvvvvvv
Work Experience-Dalton Park.pptxfvvvvvvv
 
Arduino_CSE ece ppt for working and principal of arduino.ppt
Arduino_CSE ece ppt for working and principal of arduino.pptArduino_CSE ece ppt for working and principal of arduino.ppt
Arduino_CSE ece ppt for working and principal of arduino.ppt
 
POWER SYSTEMS-1 Complete notes examples
POWER SYSTEMS-1 Complete notes  examplesPOWER SYSTEMS-1 Complete notes  examples
POWER SYSTEMS-1 Complete notes examples
 
multiple access in wireless communication
multiple access in wireless communicationmultiple access in wireless communication
multiple access in wireless communication
 
Ch10-Global Supply Chain - Cadena de Suministro.pdf
Ch10-Global Supply Chain - Cadena de Suministro.pdfCh10-Global Supply Chain - Cadena de Suministro.pdf
Ch10-Global Supply Chain - Cadena de Suministro.pdf
 
"Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ..."Exploring the Essential Functions and Design Considerations of Spillways in ...
"Exploring the Essential Functions and Design Considerations of Spillways in ...
 
Autonomous emergency braking system (aeb) ppt.ppt
Autonomous emergency braking system (aeb) ppt.pptAutonomous emergency braking system (aeb) ppt.ppt
Autonomous emergency braking system (aeb) ppt.ppt
 
Immutable Image-Based Operating Systems - EW2024.pdf
Immutable Image-Based Operating Systems - EW2024.pdfImmutable Image-Based Operating Systems - EW2024.pdf
Immutable Image-Based Operating Systems - EW2024.pdf
 
Earthing details of Electrical Substation
Earthing details of Electrical SubstationEarthing details of Electrical Substation
Earthing details of Electrical Substation
 
home automation using Arduino by Aditya Prasad
home automation using Arduino by Aditya Prasadhome automation using Arduino by Aditya Prasad
home automation using Arduino by Aditya Prasad
 
National Level Hackathon Participation Certificate.pdf
National Level Hackathon Participation Certificate.pdfNational Level Hackathon Participation Certificate.pdf
National Level Hackathon Participation Certificate.pdf
 
Energy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptxEnergy Awareness training ppt for manufacturing process.pptx
Energy Awareness training ppt for manufacturing process.pptx
 
Main Memory Management in Operating System
Main Memory Management in Operating SystemMain Memory Management in Operating System
Main Memory Management in Operating System
 
DM Pillar Training Manual.ppt will be useful in deploying TPM in project
DM Pillar Training Manual.ppt will be useful in deploying TPM in projectDM Pillar Training Manual.ppt will be useful in deploying TPM in project
DM Pillar Training Manual.ppt will be useful in deploying TPM in project
 

Characteristics of Instruments for Measurement

  • 1. kongunadu college of Engg & Tech Prepared By Tamilnesan P KNCET
  • 2. Characteristics of Instruments  There are Two types of characteristics of instruments:-  1.Static characteristics of instruments  2.Dynamic Characteristics of instruments. KNCET
  • 3. 1.Static Characteristics  The static characteristics instrument are required of an to be considered for the instruments which measure unvarying process conditions.  The static characteristics are defined for the instruments which measure quantities which do not vary with time. KNCET
  • 4. are :- 1. Accuracy 2. Sensitivity 3. Reproducibility 4. Drift 5. Static error 6. Dead zone 7. Precision 8. Threshold 9. Linearity 10. Stability 11. Range or Span 12. Bais 13. Tolerance 14. Hysteresis The main static characteristics KNCET
  • 5. 1. Accuracy It is the degree of closeness with which an instrument reading approaches the true value of the quantity being measured. The accuracy of a measurement indicates the nearness to the actual/true value of the quantity. KNCET
  • 6. 2.Sensitivity  Sensitivity is the ratio of change in output of an instrument to the change in input.  The manufactures specify sensitivity as the ratio of magnitude of the measured quantity to the magnitude of the response.This ratio is called as Inverse sensitivity or deflection factor. KNCET
  • 9. 3.Reproducibility Reproducibility is defined as the degree of closeness by which a given value can be repeatedly measured. The reproducibility is specified for a period of time. Perfect reproducibility signifies that the given readings that are taken for an input, do not vary with time.. KNCET
  • 10. KNCET
  • 11. 4.Drift The drift is defined as the gradual shift in the indication over a period of time where in the input variable does not change. Drift may be caused because of environment factors like stray electric fields, stray magnetic fields, thermal e.m.fs, changes in temperature, mechanical vibrations etc.  Drift is classified into three categories: 1. Zero drift 2. Span drift or sensitivity drift 3. Zonal drift KNCET
  • 12. 5. Static error It is the deviation from the true value of the measured variable. It involves the comparison of an unknown quantity with an accepted standard quantity. The degree to which an instrument approaches to its excepted value is expressed terms of error of measurement. KNCET
  • 13. 6.Dead zone It is the largest changes of input quantity for which there is no output. For e.g. the input that is applied to an instrument may not be sufficient to overcome friction. It will only respond when it overcomes the friction forces. KNCET
  • 14. 7.Precision It is a measure of the reproducibility of the measurement that is given a fixed value of variable. Precision is a measure of the degree to which successive measurements differ from each other. For example consider an instrument on which readings can be taken upto 1∕100th of unit. The instrument has zero adjustment error. So, when we take a readings, the instrument is highly precise. However as the instrument has a zero adjustment error the readings obtained are precise, but they are not accurate. Thus, when a set of readings show precision, the results agree among themselves. However, it is not essential that the results are accurate.KNCET
  • 16. 8.Threshsold Threshold is the smallest measurable input, below which no output change can be identified. While specifying threshold, manufactures give the first detectable output change. KNCET
  • 17. 9.Linearity Linearity is defined as the ability of an instrument to reproduce its input linearly. Linearity is simply a measure of the maximum deviation of the calibration points from the ideal straight line. Linearity is defined as, linearity=Maximum deviation of o/p from idealized straight line ∕ Actual readings KNCET
  • 18. 10.Stability The ability of an instrument to retain its performance throughout its specified storage life and operating life is called as Stability. Stability measurement instruments:- KNCET
  • 19. 11.Range or Span The minimum and maximum values of a quantity for which an instrument is designed to measure is called its range or span. Sometimes the accuracy is specified interms of range or span of an instrument. KNCET
  • 20. 12.Bais The constant error which exists over the full range of measurement of an instrument is called bias. Such a bais can be completely eliminated by calibration. The zero error is an example of bais which can be removed by calibration. KNCET
  • 21. 13.Tolerance It is the maximum allowable specified in terms of certain error that is value while measurement, it is called as tolerance. It specifies the maximum allowable deviation of a manufactured device from a mentioned value. KNCET
  • 22. 14.Hysteresis Hysteresis is a phenomenon which depicts different output effects while loading and unloading. Hysteresis takes place due to the fact that all the energy put into the stressed parts when loading is not recoverable while unloading. When the input of an instrument is varied from zero to its full scale and then if the input is decreased from its full scale value to zero, the output varies. The output at the particular input while increasing and decreasing varies because of internal friction or hysteric damping. KNCET
  • 23. KNCET
  • 24. 2.Dynamic Characteristics Instruments rarely respond to the instantaneous changes in the measured variables.Their response is slow or sluggish due to mass, thermal capacitance, electrical capacitance, inductance etc. sometimes, even the instrument has to wait for some time till, the response occurs. These type of instruments are normally used for the measurement of quantities that fluctuate with time. The behaviour of such a system, where as the input varies from instant to instant, the output also varies from instant to instant is called as dynamic response of the system. Hence, the dynamic behaviour of the system is also important as the static behaviour. KNCET
  • 25. The dynamic inputs are of two types: 1. Transient 2. Steady state periodic.  Transient response is defined as that part of the response which goes to zero as the time becomes large.  The steady state response is the response that has a definite periodic cycle. KNCET
  • 26. The variations in the input, that are used practically to achieve dynamic behaviour are: I. Step input:-The input is subjected to a finite and instantaneous change. E.g.: closing of switch. II. Ramp input:- The input linearly changes with respect to time. III. Parabolic square of input:- The input varies to the time. This represents constant input:- The input acceleration. IV. Sinusoidal accordance with a sinusoidal changes in function of constant amplitude. KNCET
  • 27. The dynamic characteristics of a measurement system are: 1) Speed of response 2) Fidelity 3) Lag 4) Dynamic error KNCET
  • 28. 1) Speed of Response instrument, responds to the changes in It is defined as the rapidity with which an the measured quantity. It shows how active and fast the system is. Speed measuring instruments:- KNCET
  • 29. 2) Fidelity It is defined as the degree to which a measurement system is capable of faithfully reproducing the changes in input, without any dynamic error. KNCET
  • 30. 3)Lag Every system requires its own time to respond to the changes in input. This time is called as lag. It is defined as the retardation or delay, in the response of a system to the changes in the input. The lags are of two types: 1. Retardation lag: As soon as there is a changes in the measured quantity, the measurement system begins to respond. 2. Time delay: The response of the measurement system starts after a dead time, once the input is applied.They cause dynamic error. KNCET
  • 31. 4)Dynamic error It is the difference between the true value of the quantity that is to be measured, changing with time and the measured value, if no static error is assumed. KNCET