This document incorporates the basics about instrumentation and measure and static and dynamic performance characteristics of instruments. Also contains statistical analysis of measurements and discuss noise and interference. Types of errors and types of noise also discussed in this document.
1. Measurement involves comparing an unknown value to a known standard using an instrument. Common instruments include indicators, recorders, and integrators.
2. Calibration ensures accurate measurements by comparing instrument readings to a primary or secondary standard over the measurement range.
3. Damping minimizes oscillations to provide steady, accurate readings by introducing opposing forces through methods like air friction, eddy currents, or fluid friction.
This presentation gives the information about Force, Pressure and Torque measurements of the subject: Mechanical measurement and Metrology (10ME32/42) of VTU Syllabus covering unit-6.
basic of measurement and instrumentation.SACHINNikam39
This document discusses instrumentation systems and measurement fundamentals. It begins by classifying instrument systems, such as absolute versus secondary instruments, analog versus digital, and mechanical versus electrical versus electronic. It then describes the functional elements of a generalized measurement system, including the primary sensing element, variable conversion element, variable manipulation element, data processing element, data transmission system, and data presentation element. Finally, it discusses standards used for calibration and measurement, categorizing them from primary reference standards to secondary, tertiary, and working standards used in inspection and workshops.
This document discusses virtual instruments. It begins with defining virtual instruments as instruments whose capabilities are determined by software running on general-purpose computers rather than dedicated hardware. The document then covers the history and evolution of virtual instruments from dedicated analog devices to computer-based instruments. It describes the typical architecture of a virtual instrument including sensor modules, processing modules, and output presentation. Finally, it provides an example virtual instrument developed in MATLAB and discusses advantages and disadvantages of virtual instruments.
The document discusses the key functional elements of measurement instruments. It describes the primary sensing element that initially converts the measured quantity into an electrical signal. It then explains how a variable conversion element may be needed to convert the output signal into a suitable form for the rest of the system. A variable manipulation element can then manipulate the signal while preserving its original nature. Finally, a data presentation element conveys the measurement information intelligibly to the user, such as through a visual display. The document also covers important performance characteristics like accuracy, precision, sensitivity and resolution that are used to evaluate instruments.
Human: You are an expert at summarizing documents. You provide concise summaries in 3 sentences or less that provide the high level and essential
1. Tachometers are instruments used to measure rotational speed and can be classified as mechanical, electrical, or contactless types based on their measurement technique.
2. Mechanical tachometers include revolution counters, hand speed indicators, tachoscopes, and centrifugal and resonance tachometers. Revolution counters measure speeds up to 2000-3000 rpm while hand speed indicators measure 20,000 to 30,000 rpm.
3. Electrical tachometers include eddy current, tachogenerator, inductive pickup, capacitive pickup, and photo-electric types. Eddy current tachometers measure up to 12,000 rpm and tachogenerators translate rotational speeds into electrical signals.
This document provides an introduction to instruments used for measurement. It discusses that an instrument is a device that determines the magnitude of a quantity being measured, such as voltage, current, power or energy. It then classifies instruments as either analog or digital. Analog instruments have outputs that are continuous functions of time with a constant relation to the input. The document describes various types of analog instruments and principles of their operation, which include magnetic, thermal, electrostatic, induction and Hall effects. It also discusses torques involved in instrument operation, including deflecting, controlling and damping torques, and methods used for damping such as air friction, fluid friction and eddy currents.
The document discusses sensors and transducers used in mechatronics systems. It defines sensors as devices that detect physical quantities and convert them into signals, while transducers convert one form of energy to another. The document outlines various types of commonly used sensors like potentiometers, strain gauges, and capacitive sensors. It describes the working principles, specifications, advantages, and applications of these sensors. The specifications discussed include range, sensitivity, accuracy, resolution, response time, which are important for mechatronics designers to understand the capabilities and limitations of different sensors.
1. Measurement involves comparing an unknown value to a known standard using an instrument. Common instruments include indicators, recorders, and integrators.
2. Calibration ensures accurate measurements by comparing instrument readings to a primary or secondary standard over the measurement range.
3. Damping minimizes oscillations to provide steady, accurate readings by introducing opposing forces through methods like air friction, eddy currents, or fluid friction.
This presentation gives the information about Force, Pressure and Torque measurements of the subject: Mechanical measurement and Metrology (10ME32/42) of VTU Syllabus covering unit-6.
basic of measurement and instrumentation.SACHINNikam39
This document discusses instrumentation systems and measurement fundamentals. It begins by classifying instrument systems, such as absolute versus secondary instruments, analog versus digital, and mechanical versus electrical versus electronic. It then describes the functional elements of a generalized measurement system, including the primary sensing element, variable conversion element, variable manipulation element, data processing element, data transmission system, and data presentation element. Finally, it discusses standards used for calibration and measurement, categorizing them from primary reference standards to secondary, tertiary, and working standards used in inspection and workshops.
This document discusses virtual instruments. It begins with defining virtual instruments as instruments whose capabilities are determined by software running on general-purpose computers rather than dedicated hardware. The document then covers the history and evolution of virtual instruments from dedicated analog devices to computer-based instruments. It describes the typical architecture of a virtual instrument including sensor modules, processing modules, and output presentation. Finally, it provides an example virtual instrument developed in MATLAB and discusses advantages and disadvantages of virtual instruments.
The document discusses the key functional elements of measurement instruments. It describes the primary sensing element that initially converts the measured quantity into an electrical signal. It then explains how a variable conversion element may be needed to convert the output signal into a suitable form for the rest of the system. A variable manipulation element can then manipulate the signal while preserving its original nature. Finally, a data presentation element conveys the measurement information intelligibly to the user, such as through a visual display. The document also covers important performance characteristics like accuracy, precision, sensitivity and resolution that are used to evaluate instruments.
Human: You are an expert at summarizing documents. You provide concise summaries in 3 sentences or less that provide the high level and essential
1. Tachometers are instruments used to measure rotational speed and can be classified as mechanical, electrical, or contactless types based on their measurement technique.
2. Mechanical tachometers include revolution counters, hand speed indicators, tachoscopes, and centrifugal and resonance tachometers. Revolution counters measure speeds up to 2000-3000 rpm while hand speed indicators measure 20,000 to 30,000 rpm.
3. Electrical tachometers include eddy current, tachogenerator, inductive pickup, capacitive pickup, and photo-electric types. Eddy current tachometers measure up to 12,000 rpm and tachogenerators translate rotational speeds into electrical signals.
This document provides an introduction to instruments used for measurement. It discusses that an instrument is a device that determines the magnitude of a quantity being measured, such as voltage, current, power or energy. It then classifies instruments as either analog or digital. Analog instruments have outputs that are continuous functions of time with a constant relation to the input. The document describes various types of analog instruments and principles of their operation, which include magnetic, thermal, electrostatic, induction and Hall effects. It also discusses torques involved in instrument operation, including deflecting, controlling and damping torques, and methods used for damping such as air friction, fluid friction and eddy currents.
The document discusses sensors and transducers used in mechatronics systems. It defines sensors as devices that detect physical quantities and convert them into signals, while transducers convert one form of energy to another. The document outlines various types of commonly used sensors like potentiometers, strain gauges, and capacitive sensors. It describes the working principles, specifications, advantages, and applications of these sensors. The specifications discussed include range, sensitivity, accuracy, resolution, response time, which are important for mechatronics designers to understand the capabilities and limitations of different sensors.
Sensors and transducers convert one form of energy into another. A sensor receives and responds to a signal, a transducer converts one form of energy to another, and an actuator converts an electrical signal to physical output. Transducers can be classified as active or passive depending on whether they require an external power source. Common transducers include resistance, capacitive, piezoelectric, hall effect, and photoelectric transducers. Key parameters for transducers include linearity, repeatability, resolution, and reliability.
Electronics measurement and instrumentation pptImranAhmad225
This document defines key concepts in measurement and instrumentation. It discusses the definition of metrology and engineering metrology. Measurement is defined as the process of numerical evaluation of a dimension or comparison to a standard. Some key methods of measurement discussed are direct, indirect, comparative, coincidence, contact, deflection, and complementary methods. The document also discusses units and standards, characteristics of measuring instruments like sensitivity, readability, range, accuracy, and precision. It defines uncertainty and errors in instruments.
Load cells are transducers that convert an applied force into an electrical signal. There are several types of load cells including resistive, capacitive, vibrating wire, piezoelectric, hydraulic, and pneumatic. Resistive load cells use strain gauges to measure deformation from applied forces. Capacitive load cells measure deformation capacitively. Vibrating wire load cells monitor loads in structural elements. Piezoelectric load cells generate voltage when force is applied to piezoelectric materials. Hydraulic load cells use fluid pressure from piston movement to measure force. Pneumatic load cells balance applied force with counteracting air pressure.
This document discusses different types of electrical and electronic instruments used for measurement and instrumentation. It describes mechanical, electrical, and electronic instruments. Mechanical instruments measure physical quantities under static conditions, while electronic instruments have a quicker response time than mechanical and electrical instruments. Electrical instruments measure electrical quantities like current, voltage, and power. Instruments can also be categorized as absolute, secondary, digital, analog, indicating, integrating, and recording based on their measurement methodology and output display.
Generalized Measurement System is a measuring system exists to provide information about the physical value of some variable being measured. In this presentation, generalized measurement system, its elements, classification of instruments, classification of measurement methods, difference between mechanical and electrical measurement systems, input output characteristics are described.
1. Indicating instruments measure electrical quantities by deflecting a pointer on a calibrated scale. They use a deflection system to produce a force proportional to the measured value, a control system to limit deflection, and a damping system to prevent oscillations.
2. Permanent magnet moving coil (PMMC) instruments have a coil mounted between magnet poles that deflects proportional to current. They are used as ammeters, voltmeters, and galvanometers. As an ammeter, the coil is connected across a low resistance shunt; as a voltmeter, it is connected in series with a high resistance.
3. Moving iron instruments can measure AC using an iron core acted on by a coil
This document discusses force and strain measurement techniques. It begins by defining force and describing Newton's second law of motion. Common force measurement methods include balancing against gravitational force, measuring deflection of an elastic member, translating to a fluid pressure, and measuring acceleration. Devices for force measurement include load cells, proving rings, and dynamometers. The document also discusses strain, strain gauges, and methods of measuring strain including resistance strain gauges, rosette gauges, mechanical strain gauges, and electrical strain gauges.
Ee2201 measurement-and-instrumentation-lecture-notesJayakumar T
This document provides an overview of electrical and electronic instruments. It discusses analog instruments and how they are classified based on the measured quantity, operating current, effects used, and measurement method. The principal of operation of common instruments is described, including magnetic, thermal, and induction effects. Specific instrument types are examined like permanent magnet moving coil meters, moving iron meters, and electrodynamometer meters. The document also covers power measurement instruments like wattmeters and energy meters for single and polyphase systems.
This course is electronics based course dealing with measurements and instrumentation designed for students in Physics Electronics, Electrical and Electronics Engineering and allied disciplines. It is a theory course based on the use of electrical and electronics instruments for measurements. The course deals with topics such as Principle of measurements, Errors, Accuracy, Units of measurements and electrical standards, , introduction to the design of electronic equipment’s for temperature, pressure, level, flow measurement, speed etc
Introduction to electrical and electronic measurement system where basics on measurement, units, static and dynamic characteristics of instruments, order of instruments, are discussed in brief. Errors in instrumentation system is discussed. Calibration and traceability of instruments are illustrated.
The instrument which gives output that varies continuously as quantity to be measured is known as analog instrument.
The instrument which gives output that varies in discrete steps and only has finite number of values is known as digital instrument.
This ppt includes measurement devices of speed measurement like various tachometers, acceleration measurement devices as well as vibration measurement devices, displacement sensing accelerometers, LVDT, piezoelectric tachometer, stroboscope.
This document discusses sensors and actuators, providing classifications of common sensors. It focuses on displacement, position, and proximity sensors, describing four main types: potentiometer sensors, strain gauge sensors, capacitive sensors, and linear variable differential transformers (LVDTs). For each sensor type, it provides the underlying measurement principle, relevant mathematical expressions, and examples of applications. The document is intended as a reference for mechatronics and manufacturing automation.
Recorders record electrical and non-electrical quantities over time to analyze processes. There are analog and digital recorders. Analog recorders include graphic recorders like X-Y and strip chart recorders that produce a pen and ink record. X-Y recorders graphically record the relationship between two variables using potentiometers to move a pen in perpendicular X and Y axes. Magnetic tape recorders record signals as magnetic patterns on tape for later playback, allowing direct high-fidelity recording of high frequencies.
This lecture introduces measurement and instrumentation. It defines measurement and instrumentation, discusses types of measurements and instruments. It reviews units of measurement, standards of measurement, and calibration. Measurement and instrumentation are used in various applications including home appliances, vehicles, and industrial processes to monitor and control parameters and improve operations.
1. Force can be measured using several principles including balancing against gravitational force, translating to fluid pressure, applying to an elastic member, or applying to a known mass and measuring acceleration.
2. Scales and balances measure force by balancing the unknown force against a known gravitational force on a standard mass. Multi-lever scales use a system of levers and counterweights to indirectly measure the applied force.
3. Elastic force meters like proving rings, beams, and springs measure the deflection or strain caused by an applied force. The deflection or strain is then related to the magnitude of the applied force.
Moving iron instruments are the most common type of ammeter and voltmeter used for laboratory or switchboard applications involving power frequencies. They can measure current and voltage with accuracy needed for most engineering works, and are cheaper than other types of AC instruments providing the same level of accuracy. Moving iron instruments are classified as either attraction type or repulsion type based on how the moving iron component moves within the instrument's coil in response to the magnetic field produced by the measured current or voltage.
The document discusses various resistance measurement techniques including the Wheatstone bridge, Kelvin bridge, and AC bridges. The Wheatstone bridge is based on balancing two voltage ratios and can measure resistances from 1 ohm to 10 megohms. The Kelvin bridge is a more precise version that eliminates errors from lead resistance and can measure down to 0.00001 ohms. AC bridges can measure impedances that include resistance, inductance, and capacitance components.
This document discusses the functional elements of a measurement system. It describes six key elements: 1) primary sensing element that detects the measured quantity, 2) variable conversion element that converts the output to a suitable form, 3) variable manipulation element that changes the signal level, 4) data transmission element that transmits data between separated elements, 5) data storage and playback element that records and replays data, and 6) data presentation element that communicates the information to users. Examples are given for each element type.
This document provides an overview of instrumentation and measurement concepts. It discusses that instrumentation deals with measurement techniques and measuring devices. Measurement involves comparing an unknown quantity to a standard.
A measurement system consists of various elements including a primary sensing element to detect the measured quantity, a transducer to convert it to another form, and elements for signal manipulation, transmission, processing, presentation and storage. Measurement methods can be direct, comparing the measured quantity directly to a standard, or indirect, using a measurement system with multiple elements. Measurements are used for process monitoring, control and experimental analysis.
1. The document discusses the syllabus for the course 20ME601 - Metrology and Measurements.
2. The syllabus is divided into 5 units which cover topics like basics of metrology, linear and angular measurements, form measurement, measurement of mechanical parameters, and advances in metrology including laser interferometers, CMM, and machine vision systems.
3. Key aspects of metrology discussed include measurement systems, standards, measurement methods and types of instruments, factors affecting accuracy and precision, and different types of errors in measurement.
Sensors and transducers convert one form of energy into another. A sensor receives and responds to a signal, a transducer converts one form of energy to another, and an actuator converts an electrical signal to physical output. Transducers can be classified as active or passive depending on whether they require an external power source. Common transducers include resistance, capacitive, piezoelectric, hall effect, and photoelectric transducers. Key parameters for transducers include linearity, repeatability, resolution, and reliability.
Electronics measurement and instrumentation pptImranAhmad225
This document defines key concepts in measurement and instrumentation. It discusses the definition of metrology and engineering metrology. Measurement is defined as the process of numerical evaluation of a dimension or comparison to a standard. Some key methods of measurement discussed are direct, indirect, comparative, coincidence, contact, deflection, and complementary methods. The document also discusses units and standards, characteristics of measuring instruments like sensitivity, readability, range, accuracy, and precision. It defines uncertainty and errors in instruments.
Load cells are transducers that convert an applied force into an electrical signal. There are several types of load cells including resistive, capacitive, vibrating wire, piezoelectric, hydraulic, and pneumatic. Resistive load cells use strain gauges to measure deformation from applied forces. Capacitive load cells measure deformation capacitively. Vibrating wire load cells monitor loads in structural elements. Piezoelectric load cells generate voltage when force is applied to piezoelectric materials. Hydraulic load cells use fluid pressure from piston movement to measure force. Pneumatic load cells balance applied force with counteracting air pressure.
This document discusses different types of electrical and electronic instruments used for measurement and instrumentation. It describes mechanical, electrical, and electronic instruments. Mechanical instruments measure physical quantities under static conditions, while electronic instruments have a quicker response time than mechanical and electrical instruments. Electrical instruments measure electrical quantities like current, voltage, and power. Instruments can also be categorized as absolute, secondary, digital, analog, indicating, integrating, and recording based on their measurement methodology and output display.
Generalized Measurement System is a measuring system exists to provide information about the physical value of some variable being measured. In this presentation, generalized measurement system, its elements, classification of instruments, classification of measurement methods, difference between mechanical and electrical measurement systems, input output characteristics are described.
1. Indicating instruments measure electrical quantities by deflecting a pointer on a calibrated scale. They use a deflection system to produce a force proportional to the measured value, a control system to limit deflection, and a damping system to prevent oscillations.
2. Permanent magnet moving coil (PMMC) instruments have a coil mounted between magnet poles that deflects proportional to current. They are used as ammeters, voltmeters, and galvanometers. As an ammeter, the coil is connected across a low resistance shunt; as a voltmeter, it is connected in series with a high resistance.
3. Moving iron instruments can measure AC using an iron core acted on by a coil
This document discusses force and strain measurement techniques. It begins by defining force and describing Newton's second law of motion. Common force measurement methods include balancing against gravitational force, measuring deflection of an elastic member, translating to a fluid pressure, and measuring acceleration. Devices for force measurement include load cells, proving rings, and dynamometers. The document also discusses strain, strain gauges, and methods of measuring strain including resistance strain gauges, rosette gauges, mechanical strain gauges, and electrical strain gauges.
Ee2201 measurement-and-instrumentation-lecture-notesJayakumar T
This document provides an overview of electrical and electronic instruments. It discusses analog instruments and how they are classified based on the measured quantity, operating current, effects used, and measurement method. The principal of operation of common instruments is described, including magnetic, thermal, and induction effects. Specific instrument types are examined like permanent magnet moving coil meters, moving iron meters, and electrodynamometer meters. The document also covers power measurement instruments like wattmeters and energy meters for single and polyphase systems.
This course is electronics based course dealing with measurements and instrumentation designed for students in Physics Electronics, Electrical and Electronics Engineering and allied disciplines. It is a theory course based on the use of electrical and electronics instruments for measurements. The course deals with topics such as Principle of measurements, Errors, Accuracy, Units of measurements and electrical standards, , introduction to the design of electronic equipment’s for temperature, pressure, level, flow measurement, speed etc
Introduction to electrical and electronic measurement system where basics on measurement, units, static and dynamic characteristics of instruments, order of instruments, are discussed in brief. Errors in instrumentation system is discussed. Calibration and traceability of instruments are illustrated.
The instrument which gives output that varies continuously as quantity to be measured is known as analog instrument.
The instrument which gives output that varies in discrete steps and only has finite number of values is known as digital instrument.
This ppt includes measurement devices of speed measurement like various tachometers, acceleration measurement devices as well as vibration measurement devices, displacement sensing accelerometers, LVDT, piezoelectric tachometer, stroboscope.
This document discusses sensors and actuators, providing classifications of common sensors. It focuses on displacement, position, and proximity sensors, describing four main types: potentiometer sensors, strain gauge sensors, capacitive sensors, and linear variable differential transformers (LVDTs). For each sensor type, it provides the underlying measurement principle, relevant mathematical expressions, and examples of applications. The document is intended as a reference for mechatronics and manufacturing automation.
Recorders record electrical and non-electrical quantities over time to analyze processes. There are analog and digital recorders. Analog recorders include graphic recorders like X-Y and strip chart recorders that produce a pen and ink record. X-Y recorders graphically record the relationship between two variables using potentiometers to move a pen in perpendicular X and Y axes. Magnetic tape recorders record signals as magnetic patterns on tape for later playback, allowing direct high-fidelity recording of high frequencies.
This lecture introduces measurement and instrumentation. It defines measurement and instrumentation, discusses types of measurements and instruments. It reviews units of measurement, standards of measurement, and calibration. Measurement and instrumentation are used in various applications including home appliances, vehicles, and industrial processes to monitor and control parameters and improve operations.
1. Force can be measured using several principles including balancing against gravitational force, translating to fluid pressure, applying to an elastic member, or applying to a known mass and measuring acceleration.
2. Scales and balances measure force by balancing the unknown force against a known gravitational force on a standard mass. Multi-lever scales use a system of levers and counterweights to indirectly measure the applied force.
3. Elastic force meters like proving rings, beams, and springs measure the deflection or strain caused by an applied force. The deflection or strain is then related to the magnitude of the applied force.
Moving iron instruments are the most common type of ammeter and voltmeter used for laboratory or switchboard applications involving power frequencies. They can measure current and voltage with accuracy needed for most engineering works, and are cheaper than other types of AC instruments providing the same level of accuracy. Moving iron instruments are classified as either attraction type or repulsion type based on how the moving iron component moves within the instrument's coil in response to the magnetic field produced by the measured current or voltage.
The document discusses various resistance measurement techniques including the Wheatstone bridge, Kelvin bridge, and AC bridges. The Wheatstone bridge is based on balancing two voltage ratios and can measure resistances from 1 ohm to 10 megohms. The Kelvin bridge is a more precise version that eliminates errors from lead resistance and can measure down to 0.00001 ohms. AC bridges can measure impedances that include resistance, inductance, and capacitance components.
This document discusses the functional elements of a measurement system. It describes six key elements: 1) primary sensing element that detects the measured quantity, 2) variable conversion element that converts the output to a suitable form, 3) variable manipulation element that changes the signal level, 4) data transmission element that transmits data between separated elements, 5) data storage and playback element that records and replays data, and 6) data presentation element that communicates the information to users. Examples are given for each element type.
This document provides an overview of instrumentation and measurement concepts. It discusses that instrumentation deals with measurement techniques and measuring devices. Measurement involves comparing an unknown quantity to a standard.
A measurement system consists of various elements including a primary sensing element to detect the measured quantity, a transducer to convert it to another form, and elements for signal manipulation, transmission, processing, presentation and storage. Measurement methods can be direct, comparing the measured quantity directly to a standard, or indirect, using a measurement system with multiple elements. Measurements are used for process monitoring, control and experimental analysis.
1. The document discusses the syllabus for the course 20ME601 - Metrology and Measurements.
2. The syllabus is divided into 5 units which cover topics like basics of metrology, linear and angular measurements, form measurement, measurement of mechanical parameters, and advances in metrology including laser interferometers, CMM, and machine vision systems.
3. Key aspects of metrology discussed include measurement systems, standards, measurement methods and types of instruments, factors affecting accuracy and precision, and different types of errors in measurement.
This document provides an overview of metrology and measurement concepts. It discusses the introduction to metrology, the need for measurement, components of a generalized measurement system, types of standards, units of measurement, types of measurements/methods of measurement, types of measuring instruments, accuracy vs precision, and factors affecting accuracy and precision. It also defines types of errors in measurement such as gross errors, measurement errors, systematic errors, and random errors.
This document provides an overview of metrology and measurement concepts. It discusses the introduction to metrology, the need for measurement, components of a generalized measurement system, types of standards, units of measurement, types of measurements/methods of measurement, types of measuring instruments, accuracy vs precision, and factors affecting accuracy and precision. It also defines types of errors in measurement such as gross errors, measurement errors, systematic errors, and random errors.
1. The document discusses the syllabus for the course 20ME601 - Metrology and Measurements.
2. The syllabus is divided into 5 units which cover topics like basics of metrology, linear and angular measurements, form measurement, measurement of mechanical parameters, and advances in metrology.
3. Key concepts discussed include types of metrology, components of a generalized measurement system, standards, units, types of measurements/methods of measurements, types of measuring instruments, factors affecting accuracy and precision, and types of errors in measurements.
Metrology Measurements and All units PPTdinesh babu
Metrology is the science of measurement, embracing both experimental and theoretical determinations at any level of uncertainty in any field of science and technology
This document outlines the course objectives and syllabus for a Measurements and Instrumentation course.
The course aims to: [1] Familiarize students with measuring instrument characteristics and concepts of analog and digital instruments; [2] Teach students how to evaluate instrument performance using bridges, transducers, and different measurement techniques; and [3] Demonstrate various transducers and sensors used to measure physical quantities.
The syllabus covers 5 units - science of measurements, analog instruments, digital instruments, comparative measurement methods, and transducers and data acquisition systems. Key topics include instrument elements, static and dynamic performance, error analysis, and an overview of common measurement devices.
Metrology is the science of measurement. It has three main tasks: defining measurement units, realizing measurement units through scientific methods, and establishing traceability in documenting measurement accuracy. Metrology is essential in scientific research and various industries. It covers establishing standards, developing measurement methods, analyzing errors, and ensuring instrument accuracy. Metrology helps plan lives and enable commercial exchanges with confidence as measurements can be seen everywhere.
1. This document discusses instrumentation and measurement systems. It defines instrumentation as the science of measurement and control.
2. A measurement system consists of four main functional blocks - a sensing element, signal conditioning, signal processing, and data presentation. The sensing element detects the input quantity and produces a corresponding output. Signal conditioning prepares the output for further processing.
3. The performance of a sensing element is characterized by its static and dynamic characteristics. Static characteristics describe the sensor's performance when the input is constant or changing slowly, and include properties like range, sensitivity, linearity, and accuracy.
This document provides an overview of electrical and electronic measurements. It discusses measurement systems and instruments, including various types of analog and digital meters, bridges for measuring resistance, inductance and capacitance, signal generators and oscilloscopes. Measurement methods can be direct or indirect, with indirect using a transducer and processing the signal. Key aspects covered include instrument components, types of instruments, and their functions such as indicating, recording and integrating measurements.
This document provides an introduction to measurement systems and concepts. It discusses the classification of standards including primary, secondary, international, and working standards. It also describes the International System of Units (SI) which defines the seven base units of the metric system. Measurement methods are classified as direct comparison using deflection instruments or null balance comparisons, and indirect methods. Direct methods measure the unknown quantity while indirect determine it through a related measured value.
These slides describes the deifintion of measurement, Classification of instruments and methods of measurement.
Read the full blog post here: https://bit.ly/32prjeT
An energy audit document outlines the process and key aspects of conducting an energy audit. It begins with definitions of an energy audit and why they are needed to identify opportunities to lower energy costs. The document then describes the different types of energy audits from preliminary to targeted to detailed. For detailed audits, it provides a 10 step process including planning, data collection, analysis, identification of conservation opportunities, and reporting. Key audit instruments and factors to examine like production processes, energy usage, benchmarks, and monitoring are also outlined. The goal is to comprehensively evaluate energy usage and identify technical and economically feasible recommendations to improve efficiency.
1) Measurement involves quantitatively comparing an unknown quantity to a standard unit of measurement. Measurements are important for research, development, and evaluating system performance.
2) Instruments are devices used to determine the value of a physical quantity. Instrumentation is the technology of using instruments to measure properties.
3) There are direct and indirect methods of measurement. Direct involves comparing the unknown quantity directly to a standard, while indirect uses a secondary standard and calibration.
The document discusses measurement systems and their components. It describes how a generalized measurement system consists of three main elements - a transducer element that senses the input, a signal conditioning element that processes the output, and a data presentation element that provides the measurement results. It provides examples of different types of transducers and measurement instruments, and explains the desirable characteristics of transducer elements, including being sensitive only to the desired input and providing an accurate electrical output signal.
An instrument may be defined as a machine or system which is designed to maintain functional relationship between prescribed properties of physical variables & could include means of communication to human observer
Ch-4: Measurement systems and basic concepts of measurement methodsSuraj Shukla
This document provides an introduction and overview of measurement systems and concepts. It discusses:
- The basic components of a generalized measurement system, including sensing, conversion, manipulation, processing, transmission and presentation stages.
- Key definitions and concepts in measurement like accuracy, error, calibration, threshold, sensitivity and hysteresis.
- Classification schemes for transducers based on factors like the physical phenomenon, power type, output type and electrical phenomenon.
- Types of transducers like active vs passive, primary vs secondary, analog vs digital, and examples within resistive, capacitive, inductive and other categories.
This document discusses basic principles of measurements. It defines key terms like measurement, instrument, measurand and describes different types of measurement methods, standards, and performance characteristics of instruments. Specifically, it outlines direct and indirect comparison methods of measurement and discusses primary, secondary and working standards. It also categorizes instruments as mechanical, electrical, electronic; and defines static performance characteristics like accuracy, precision, error, range and resolution.
JNTUK v semester electronics and communication engineering subject unit 1 ppt
A smart sensor is a device that takes input from the physical environment and uses built-in compute resources to perform predefined functions upon detection. A smart sensor is a device that takes input from the physical environment and uses built-in compute resources to perform predefined functions upon detection of specific input and then process data before passing it on. How do sensors work?
Most sensors use radiation such as light or laser, infrared, radio waves or other waves such as ultrasonic waves to detect objects and changes in their environment. They can do so by having an energy source inside them that enables them to emit the radiation towards their target object.
This document provides an introduction to instrumentation and measurement. It discusses:
1. The importance of measurement in science, engineering, and daily life. Measurement allows the study of natural phenomena and supports technological advancement.
2. Key concepts in instrumentation including transducers that convert physical quantities to electrical signals, and functional elements like sensing, signal conversion/manipulation, transmission, and display.
3. Performance characteristics of instruments including static characteristics like accuracy, precision, resolution, sensitivity, and errors, and dynamic characteristics related to rapidly changing measurements. Calibration is also discussed.
4. Sources of errors in measurement including gross errors from human mistakes, systematic errors from instruments, environments, and observations, and random errors
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ACEP Magazine edition 4th launched on 05.06.2024Rahul
This document provides information about the third edition of the magazine "Sthapatya" published by the Association of Civil Engineers (Practicing) Aurangabad. It includes messages from current and past presidents of ACEP, memories and photos from past ACEP events, information on life time achievement awards given by ACEP, and a technical article on concrete maintenance, repairs and strengthening. The document highlights activities of ACEP and provides a technical educational article for members.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELgerogepatton
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
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CHAPTER ONE: Introduction to Instrumentation and Measurement.pptx
1. Chapter One
Introduction to Measurement &
Instrumentation
AMU-SC | Ashenafi B. 1
Arba Minch University
Sawla Campus
Department of Electromechanical Engineering
Course: Instrumentation Engineering & Measurement
(EMEg4262)
Instructor:
Mr. Tadesse, A.B. (Control & Instrumentation Engineer)
2. Why do we measure parameters?
• To understand, or reveal insight and predict
variables.
• In the case of industry, to improve quality and
efficiency, and to maintain proper operation.
• Measuring is the process of learning about the
parameters.
• Different scholar quote:
“If you can’t measure it, you can’t improve it.”
AMU-SC | Ashenafi B. 2
3. Introduction
Measurement and Instrumentation
• Measurement:– the process of determining the quantity
of a variable by means of appropriate measuring
instruments.
• It is a comparison between a standard and what we want
to measure (the measurand).
• A method to obtain information regarding the physical
values of the variables.
AMU-SC | Ashenafi B. 3
4. Cont’d
• Basic requirements for a meaningful measurement is:
the standard used for comparison purposes must be accurately defined
and should be commonly accepted.
the apparatus used and the method adopted must be provable
(verifiable).
• Measurement involve the use of instruments as a physical
means of determining quantities or variables.
• Because of modular nature of the elements within it, it is
common to refer the measuring instrument as a
measurement system.
AMU-SC | Ashenafi B. 4
5. Instrumentation
• Instrumentation is a collective term for measuring
instruments that are used for measuring,
indicating and recording physical quantities.
• Instrumentation is the design, equipping, and/or
use of measuring instruments in determining real-
life conditions in a plant's process, as for
observation, measurement and control.
AMU-SC | Ashenafi B. 5
6. Evolution of Instruments
Mechanical
Instrument
Electrical
Instrument
Electronic
Instrument
• Very reliable for static and stable conditions, however
unable to respond rapidly to measurements of dynamic
and transient conditions.
• Indicating the output are rapid than
mechanical methods, however it
depends on the mechanical movement
of the meters.
• It is more reliable than other system.
• It uses semiconductor devices and
weak signal can also be detected.
AMU-SC | Ashenafi B. 6
7. • An instrument is a device in which we can determine the magnitude or value
of the quantity to be measured.
• The measuring quantity can be voltage, current, power, energy and etc.
• Generally, instruments are classified in to two categories:
Classification of Instruments
Instrument
Absolute
Instrument
Secondary
Instrument
AMU-SC | Ashenafi B. 7
8. Absolute/primary instrument determines the magnitude of the quantity to be measured in terms of
the instrument parameter.
We have to calculate the magnitude of the measuring quantity, analytically which is time consuming,
because each time the value of the measuring quantities varies.
These types of instruments are suitable for laboratory use.
Example: Tangent galvanometer (for current measurement)
Cont’d
From figure, B=Bh tanθ. This is known as
tangent law of magnetism.
AMU-SC | Ashenafi B. 8
9. Secondary instrument: determines the value of the quantity to be measured
directly.
Generally, these instruments are calibrated by comparing with another standard
secondary instrument.
Examples: voltmeter, ammeter, wattmeter, and etc.
Cont’d
AMU-SC | Ashenafi B. 9
10. • Indicating Instrument:
This instrument uses a dial and pointer to determine the value of measuring
quantity. The pointer indication gives the magnitude of measuring quantity.
• Recording Instrument:
This type of instruments records the magnitude of the quantity to be
measured continuously over a specified period of time.
• Integrating Instrument:
This type of instrument gives the total amount of the quantity to be
measured over a specified period of time.
Cont’d
AMU-SC | Ashenafi B. 10
11. Functional Elements of Measuring System
• The main functional elements of a measurement system are:
I. primary sensing element;
II. variable conversion element;
III. variable manipulation element;
IV. data transmission element;
V. data presentation element; and
VI. data storage and playback element
Data Conditioning Element
AMU-SC | Ashenafi B. 11
13. Primary Sensing Elements:
The quantity or the variable which is being measured (i.e., CURRENT) makes its first
contact with primary sensing element (i.e., COIL) of measurement.
PSE receives signal of the physical quantity to be measured as a I/P (input) with help of
detector.
Variable Conversion Element:
The measured signal is then immediately converted into a suitable form; it may be a
analogous electrical signal, mechanical signal or any other form using transducer.
For the instrument to perform the desired function, it may be necessary to convert this
output to some other suitable form.
Cont’d
AMU-SC | Ashenafi B. 13
14. Variable Manipulation Element:
The function of this element is to manipulate the signal presented to it preserving the
original nature of the signal.
Data Presentation Element:
The information about the quantity under measurement has to be conveyed to the
personnel handling instrument or the system for monitoring, control, or analysis purposes.
This function is done by data presentation element.
In case data is to be monitored, visual display devices are needed. These devices may be
analog or digital indicating instruments like ammeters, voltmeters etc.
Cont’d
AMU-SC | Ashenafi B. 14
15. In case data is to be recorded, recorders like magnetic tapes, high speed camera &
TV equipment, CRT, printers may be used.
Example: Ammeter
Cont’d
AMU-SC | Ashenafi B. 15
16. Function of Measurement System
• Functions of instrument and measuring system can be classified into
four major parts. They are:
I. Indicating Function: supplying information concerning the variable quantity
under measurement.
II. Recording Function: the instrument makes a written record, usually on
paper, of the value of the quantity under measurement against time or against
some other variable.
III. Signal Processing: modifying the measured signal to facilitate recording /
control.
IV. Controlling Function: the system to control the original measured variable
or quantity.
AMU-SC | Ashenafi B. 16
17. Application of Measurement System
• Before discussing the instrument characteristics, construction and
working, it is pertinent to understand the various ways in which the
measuring instruments are put in use.
• Different applications of the instruments and measurement systems
are:
i. Monitoring a process/operation: indication the value/condition of
parameter.
ii. Control a process/operation: corrective action
iii. Experimental engineering analysis: to find out solution of the
engineering problems.
AMU-SC | Ashenafi B. 17
18. Control a Process
• Measurement of a variable and
its control are closely
associated.
• To control a process variable,
e.g., temperature, pressure or
humidity etc., the prerequisite
is that it is accurately
measured at any given instant
and at the desired location.
Figure: Process control system.
AMU-SC | Ashenafi B. 18
19. Unit of Measurement & Dimensions
• The standard measure of each kind of physical quantity is called a
unit.
1. CGS system: called Gaussian system of units.
• In this length, mass and time have been chosen as the fundamental
quantities and corresponding fundamental units are centimetre (cm),
gram (g) and second (s) respectively.
2. MKS system: called Giorgi system of unit.
• In this system also length, mass and time have been taken as
fundamental quantities, and the corresponding fundamental units are
metre, kilogram and second.
AMU-SC | Ashenafi B. 19
20. 3. FPS system: In this system foot, pound and second are used
respectively for measurements of length, mass and time.
• In this system force is a derived quantity with unit poundal.
4. SI System: It is known as International system of units, and is
extended system of units applied to whole physics.
• There are seven fundamental quantities in this system.
Cont’d
AMU-SC | Ashenafi B. 20
21. S.No. Basic Quantity Name Symbol
1 Length Meter M
2 Mass Kilogram Kg
3 Time Second S
4 Electric Current Ampere A
5 Temperature Kelvin k
6 Amount of Substance Mole Mol
7 Luminous Intensity Candela Cd
Cont’d
AMU-SC | Ashenafi B. 21
22. • Units are sub-divided into 2 categories:
1. Fundamental units
2. Supplementary and Derived units
1. Fundamental units: units for fundamental or base quantities (like
length, mass, time, etc.).
• It was developed and recommended by general conference on weights
and measures in 1971.
Cont’d
AMU-SC | Ashenafi B. 22
23. Derived Units: Other physical quantities derived from the base quantities can be
expressed as a combination of the base units.
Examples:
Force(f) = Mass x acceleration = m x a = kg ms-2 (newton, N)
Pressure(p) = force/area = (f/a) = kg ms-2/m2 (pascal, pa)
Frequency(f) = 1/period = (1/T) = 1/s = s-1 (hertz, hz)
Cont’d
AMU-SC | Ashenafi B. 23
24. • Supplementary Units: there are two supplementary units, which are shown in
table below:
• Dimensions: are the representation of physical quantities or derived quantities
in the form of fundamental quantities without its numerical values.
S.No.
Supplementary Fundamental
Quantities
Supplementary
Unit
Symbol
1 Plane angle radian rad
2 Solid angle steradian Sr
Cont’d
AMU-SC | Ashenafi B. 24
27. Standard
• Mainly used for calibration purpose.
• Standards are used to determine the values of other physical quantities
by comparison method.
1. International Standards
• International standards are defined by the international agreement.
These standards are maintained at the international bureau of weights
and measures and are periodically evaluated and checked by absolute
measurements in terms of fundamental units of physics.
• These international standards are not available to the ordinary users
for the calibration purpose.
AMU-SC | Ashenafi B. 27
28. Example: International ohms, amperes, etc.
Note: international standard units are replaced in 1948 by absolute units (these units are
more accurate).
1 international ohm = 1.00049 absolute ohm
1 international ampere = 0.99985 absolute ampere
2. Primary Standards
These primary standards are maintained at national standard laboratories in different
countries.
These are not available for use, outside the national laboratories.
The main function of the primary standards is the calibration and verification of
secondary standards.
Cont’d
AMU-SC | Ashenafi B. 28
29. 3. Secondary Standards
These are used by the measurement and calibration laboratories in industries
and are maintained by the particular industry to which they belong.
Each industry has its own standards.
4. Working Standards
These standards are used to check and calibrate laboratory instruments for
accuracy and performance.
Example: manufacturers of electronic components such as Capacitors, Resistors
etc.. use working standards for checking the component values being manufactured.
Cont’d
AMU-SC | Ashenafi B. 29
30. Calibration
• Calibration of all instruments is important since it affords
the opportunity to check the instruments against a known
standard and subsequently to find errors and accuracy.
• Calibration procedure involve a comparison of the
particular instrument with either
a Primary standard;
a secondary standard with a higher accuracy than the instrument
to be calibrated; or
an instrument of known accuracy.
AMU-SC | Ashenafi B. 30
31. • Error is the deviation of the true value from the desired value or the difference between the
measured value and the actual value.
True value: the average value of an infinite number of measured values.
Measured value: the estimated value of true value.
• Error may be expressed either as absolute error or percentage error
Absolute Error:
E = Yn - Xn
Where, E = Absolute error, Yn=Expected value and Xn=Measured value
Percentage Error / Percentage Relative Error:
Er = {[Yn - Xn] / Yn} x 100
Where, Er = Relative error
Error
AMU-SC | Ashenafi B. 31
32. Accuracy
• The degree of exactness (closeness) of a measurement compared to the expected
(desired) value. Or how close a measured value is to the actual value
• In most instrument, the accuracy is guaranteed within a certain percentage of full
scale reading.
Note: Percentage error is more frequently expressed as accuracy rather than error.
Therefore,
A = 1 – Er = 1 - {[Yn - Xn] / Yn}
AMU-SC | Ashenafi B. 32
33. Precision
• A measure of the consistency or repeatability of measurement. (or) it is the
consistency of the instrument output for a given value of input. (or) how close the
measured values are to each other (in each iteration).
Note: The accuracy and precision of an instrument depends upon its design,
material used, and workmanship that goes into making of the instrument.
AMU-SC | Ashenafi B. 33
35. Types of Errors
a) Gross Error (Human Error)
• These errors are due to human in reading and recording or lack of experience
while taking the measurement values.
• The values of gross errors will vary from observer to observer.
• Sometimes, the gross errors may also occur due to improper selection of the
instrument.
• We can minimize the gross errors by following these two steps.
Choose the best suitable instrument, based on the range of values to be
measured.
Note down the readings carefully.
AMU-SC | Ashenafi B. 35
36. b) Systematic Error
• If the instrument produces an error, which is of a constant uniform deviation during its operation is
known as systematic error.
• The systematic errors that occur due to fault in the measuring device (i.e., defective or worn parts
or ageing or environment effect on the instrument), or occur due to the characteristics of the
materials used in the instrument.
Types of Systematic Errors
• The systematic errors can be classified into the following three types.
I. Instrumental Errors: occur due to wrong construction of the measuring instruments
(i.e., shortcomings of the instrument & loading effect).
II. Environmental Errors: occur due to some external conditions mainly change in
environment such that change in pressure, temperature, humidity or due to magnetic
field. These errors are avoided by air-conditioning, sealing certain components, using
magnetic shield, etc.…
Cont’d
AMU-SC | Ashenafi B. 36
37. III. Observational Errors: occurs due to wrong observations or reading in the
instruments. Parallax errors belong to this type of errors.
• In order to reduce the PARALLAX error highly accurate meters are needed:
meters provided with mirror scales.
c) Random Errors
• Random errors are caused by the sudden change in experimental conditions or
noise or tiredness in the working persons.
• Hence, it is not possible to eliminate or minimize these errors.
Example: sudden changes in humidity, unexpected change in temperature and
fluctuation in voltage.
• These errors may be reduced by taking the average (i.e., statistical analysis) of
a large number of readings.
Cont’d
AMU-SC | Ashenafi B. 37
38. Performance Characteristics of Instruments
• The performance characteristics of an instrument are mainly divided
in two categories:
1. Static Characteristics: used to measure the quantities which are
slowly varying with time or mostly constant.
2. Dynamic Characteristics: when the quantity under measurement
changes with time, it is necessary to study the dynamic relations
existing between input and output.
• Dynamic relations of parameters are generally expressed with the help
of differential equations.
AMU-SC | Ashenafi B. 38
39. Static Characteristics
1. Accuracy
2. Precision
3. Sensitivity / Sensitivity Drift
4. Range / span
5. Linearity
6. Threshold
7. Hysteresis
8. Resolution
• The various static characteristics are:
AMU-SC | Ashenafi B. 39
40. 1. Accuracy
• It is concerned on how close a measured value is to the actual value. The accuracy
can be expressed in the following ways.
I. Accuracy as ‘Percentage of Full Scale Reading’
• In case of instrument having uniform scale, the accuracy can be expressed as
percentage of full scale reading.
Example: the accuracy of an instrument having full scale reading of 50 units may
be expressed as ±0.1% of full scale reading. From this accuracy indication,
practically accuracy is expressed in terms of limits of error.
AMU-SC | Ashenafi B. 40
41. • So for the accuracy limits specified above, there will be ±0.05 units
error in any measurement.
• So for a reading of 50 units, there will be error of ±0.05 units i.e.
±0.1%, while for a reading of 25 units, there will be error of ±0.05
units in the reading i.e. ±0.2%.
II. Accuracy as ‘Percentage of True Value’
• This is the best method of specifying the accuracy.
• It is to be specified in terms of the true value of quantity being
measured.
For example: it can be specified as ±0.1% of true value.
Cont’d
AMU-SC | Ashenafi B. 41
42. III. Accuracy as ‘Percentage of Scale Span’
• For an instrument, if amax is the maximum point for which scale is
calibrated (i.e., full scale reading) and amin is the lowest reading on
scale; then (amax - amin) is called scale span or span of the instrument.
• Thus, for an instrument having range from 25 units to 225 units, it can
be specified as ±[(0.2/100) x (225-25)] (i.e., ±0.2%.) which is ±0.4 units
error in any instrument.
IV. Point Accuracy
• Such an accuracy is specified at only one particular point of scale.
• It does not give any information about the accuracy at any other point
on the scale.
Cont’d
AMU-SC | Ashenafi B. 42
43. 2. Precision
• It is the measure of the consistency or repeatability of the measurements.
• The precision is composed of two characteristics.
i. Conformity: compliance with standards, or measurement matching with desired value.
ii. Number of significant figures: precision of the measurement is obtained from the number
of significant figures, in which the reading is expressed.
For example: a resistance of 110Ώ, specified by an instrument may be closer to 109Ώ or
110Ώ. Thus, there are 3 significant figures.
• While if it is specified as 110.0Ώ, then is may be closer to 110.1Ώ or 109.9Ώ. Thus, there
are also 3 significant figures.
AMU-SC | Ashenafi B. 43
44. 3. Sensitivity
• The sensitivity denotes the smallest change in the measured variable to which the
instrument responds.
• It denotes as the ratio of the changes in the output to a change in the value of the
quantity to be measured (input).
AMU-SC | Ashenafi B. 44
45. Cont’d
Example: Sensitivity of a spring balance can be expressed as 25 mm/kg (say), indicating
additional load of 1 kg will cause additional displacement of the spring by 25mm
• Deflection factor (Inverse sensitivity) = 1/Sensitivity
AMU-SC | Ashenafi B. 45
46. 4. Sensitivity Drift
• It defines the amount by which an instrument’s sensitivity of measurement varies as
ambient conditions change (i.e., due to external conditions).
• In order to avoid such sensitivity drift, sophisticated instruments are either kept at
controlled temperature, or suitable in-built temperature compensation schemes are
provided inside the instrument.
Example:
• Suppose the sensitivity of the spring
balance mentioned above is 25 mm/kg at
20 oC and 27 mm/kg at 30oC.
• Then, the sensitivity drift/oC is 0.2
(mm/kg)/oC.
AMU-SC | Ashenafi B. 46
47. 5. Resolution/Discrimination
• The smallest change in input reading that can be traced accurately, or
It defines the smallest change in measured quantity that causes a
observable change in its output.
For example: In a temperature transducer, if 0.2oC is the smallest
temperature change that observed, then the measurement resolution is
0.2oC.
Note:
• Resolution is the smallest portion of the signal that can be observed, whereas
Sensitivity is the smallest change in the signal that can be detected.
AMU-SC | Ashenafi B. 47
48. 6. Hysteresis
• Hysteresis is basically dependence on the state of a system on its
history.
• It is non-coincidence of loading and unloading whether it is an
electrical or a mechanical system.
• Which means, for an instrument or system, when an input varies from
zero to full scale and then back to zero, its output varies.
• It can occur due to gear backlash in mechanism, magnetic
hysteresis or due to elastic hysteresis.
AMU-SC | Ashenafi B. 48
49. For example: a magnetic hysteresis is shown below. It is characteristics
of flux density, B and magnetizing force, H.
• There are two outputs in hysteresis for increasing and decreasing the
value of the input.
Cont’d
AMU-SC | Ashenafi B. 49
50. 7. Linearity
• Linearity is the static characteristics of an instrument or measurement system, in
which output is linearly proportional to the input.
• It also defined as the maximum deviation from the linear characteristics as
percentage of the full-scale output.
AMU-SC | Ashenafi B. 50
51. • If the input to an instrument is gradually increased from zero, the input will have
to reach a certain minimum level before the change in the instrument’s output
reading.
• This minimum value of input below which no output can be appeared is known as
the threshold of the instrument.
Example: Eddy current Speedometer used in automobiles, typically have a
threshold of about 15km/h.
8. Threshold
AMU-SC | Ashenafi B. 51
52. 9. Zero Drift
• It describes the effect where the zero reading of an instrument is modified by a
change in ambient conditions.
• Zero drift is normally removable by calibration.
AMU-SC | Ashenafi B. 52
53. • Dead space is defined as the range of different input values over
which there is no change in output value.
10. Dead Zone / Dead Space
AMU-SC | Ashenafi B. 53
54. 11. Range
• The input range of an measuring device is specified by the minimum
and maximum values of input variable (Xmin to Xmax).
For example: from -10 to +150 oC (for the measurement device with
temperature input).
• The output range of a measuring device is specified by the minimum
and maximum values of output variable (Ymin to Ymax).
AMU-SC | Ashenafi B. 54
55. 12. Span
• The input span of a measuring devices is specified by the difference
between maximum (Xmax) and minimum (Xmin) values of input
variables: (Xmax - Xmin ).
• In the case of a thermometer, its scale goes from −40°C to 100°C.
Thus, its span is 140°C.
AMU-SC | Ashenafi B. 55
56. Dynamic Characteristics
• The various dynamic characteristics are:
1. Speed of response
2. Measuring lag
3. Fidelity
4. Dynamic error
AMU-SC | Ashenafi B. 56
57. • Speed of response: the rapidity with which a measurement system
responds to changes in the measured quantity.
• Measuring lag: retardation delay in the response of a measurement
system to changes in the measured quantity.
It is of 2 types:
I. Retardation type: The response begins immediately after a change in
measured quantity has occurred, but have a slow progress.
II. Time delay: The response of the measurement system begins after a dead
zone after the application of the input.
Cont’d
AMU-SC | Ashenafi B. 57
58. • Dynamic error:
• Otherwise called as measurement error.
• Difference between the true value of the quantity changing with time and the
value indicated by the measurement system (i.e., provided no static error is
assumed).
• Fidelity: degree to which a measurement system indicates changes in
the measurand quantity without dynamic error.
Cont’d
AMU-SC | Ashenafi B. 58
59. Statistical Evaluation of Measurement Data
• Out of all the various possible errors, the random errors cannot be determined in
the ordinary process of measurements. However, these errors can be treated
mathematically.
• The mathematical analysis of the various measurements is called statistical
analysis of the data.
• For statistical analysis, the same reading is taken number of times, generally using
different observers, different instruments & by different ways of measurement.
• The statistical analysis helps to determine analytically the uncertainty of the final
test results.
• From statistical analysis tools, some are:
Arithmetic mean & median
Average deviation
AMU-SC | Ashenafi B. 59
60. 60
Arithmetic Mean
• The most probable value of measured variable is the arithmetic
mean of the number of readings taken.
• It is given by:
Where, = arithmetic mean
x1, x2, …, x3 = reading of samples
n = number of readings
n
x
n
x
x
x
x n
.....
2
1
x
AMU-SC | Ashenafi B.
61. 61
Deviation
• Deviation is departure of the observed reading from the arithmetic
mean of the group of readings.
0
)
...
(
)
(
..
)
(
)
(
)
(
0
.....
3
2
1
3
2
1
3
2
1
3
3
2
2
1
1
X
n
X
n
X
n
x
x
x
x
X
x
X
x
X
x
X
x
ie
d
d
d
d
X
x
d
X
x
d
X
x
d
X
x
d
n
n
n
n
n
AMU-SC | Ashenafi B.
62. 62
Standard Deviation
• The average amount of variability in the database.
• The standard deviation of an infinite number of data is defined as
the square root of the sum of the individual deviations squared
divided by the number of readings.
n
observatio
n
d
n
d
d
d
d
s
D
S
n
observatio
n
d
n
d
d
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n
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20
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.
20
...
.
2
2
2
3
2
2
2
1
2
2
2
3
2
2
2
1
Note: ‘n-1’ is a Bessel’s correction to remove biasness from square root, or to
yield unbiased variance.
AMU-SC | Ashenafi B.
63. 63
Variance
n
observatio
n
d
s
D
S
Variance
n
observatio
n
d
D
S
Variance
20
1
.
20
.
2
2
2
2
2
2
• The expectation of the squared deviation of a random variable
from its population mean or sample mean.
AMU-SC | Ashenafi B.
64. 64
Probable Error
• Regular deviation within a determined distance on each side of the mean of a
frequency curve.
• It is the value that added or subtracted from the coefficient of correlation (r) to get
the upper & lower limit respectively, within which the value of the correlation
expectedly lies.
• Probable error of one reading (r1),
r1 = 0.6745 * S.D.
• Probable error of mean (rm):
1
1
n
r
rm
AMU-SC | Ashenafi B.
65. 65
Problem
Question: The following 10 observation were recorded when
measuring a voltage:
41.7, 42.0, 41.8, 42.0, 42.1, 41.9, 42.0, 41.9, 42.5, 41.8 volts.
1. Mean
2. Standard Deviation
3. Probable Error
4. Range and Span.
AMU-SC | Ashenafi B.
66. 66
Answer
• Mean = 41.97 volt
• S.D = 0.22 volt
• Probable error of a single observation (r1) = 0.15 volt
• Probable error of mean (rm) = 0.05
• Range = 41.7 volt to 42.5 volt
• Span = 0.8 volt.
AMU-SC | Ashenafi B.
68. • Noise: can be characterized as any disturbance that tends to obscure
a desired signal. It can be generated within a circuit or picked up from
external nature or artificial sources.
• Interference: is noise that tends to obscure the useful signal. It is
usually caused by electrical sources, but can be induced from other
physical sources such as mechanical vibration, acoustical feedback, or
electrochemical sources.
• The distinction between interference and noise is that interference is
artificial noise (radio frequency jammer) while noise can be natural
(thermal noise) or man made.
Cont’d
AMU-SC | Ashenafi B. 68
69. Classification/Source of Noise
• Internal Noise
1. Thermal Noise: caused by the random motion of charged particles in the
sensors and amplifiers.
2. Contact Noise: excess noise, flicker noise, or pink noise.
3. Shot Noise: originates from the discrete nature of electric charge (i.e.,
random fluctuation of DC current), or from quantum mechanical events.
• External Noise
1. Conductive Coupling: a power line transmits surge, ripple, and spike noise.
2. Electric and Magnetic Field: capacitive coupled interference & magnetic
field interference.
3. Power Line Interference: caused by an external source that introduces
unwanted voltage in the circuit, called hum in audio system.
AMU-SC | Ashenafi B. 69
70. AMU-SC | Ashenafi B. 70
Effects of Noise
• Affects operation stability and performance of the system.
• Reduces accuracy and repeatability of measurements.
• Introduces distortion in sound signals.
• Introduces errors in control systems.
71. • RMS (Root Mean Square) value:
T
n
rms
n dt
t
v
T
v 0
2
,
1
where T is a suitable averaging time interval. A longer T usually gives a more accurate
rms measurement.
• It indicates the normalized noise power of the signal.
• Signal-to-Noise ratio (SNR) (in dB):
• Noise Summation:
rms
n
rms
x
rms
n
rms
x
v
v
v
v
power
noise
power
signal
SNR
,
,
2
,
2
,
log
20
log
10
log
10
vn2(t)
vn1(t)
vno(t)=vn1(t)+vn2(t)
=
sources
signal
two
the
between
n
correlatio
T
n
n
values
squared
mean
individual
rms
n
rms
n
T
n
n
rms
no
dt
t
v
t
v
T
v
v
dt
t
v
t
v
T
v
0 2
1
2
,
2
2
,
1
0
2
2
1
2
,
2
1
Noise Analysis
AMU-SC | Ashenafi B.
71
72. AMU-SC | Ashenafi B. 72
What to Do?
How can we eliminate or reduce the undesirable effects of noise?
• Grounding/shielding electrical connections;
• Filtering (smoothing);
• Averaging several measurements;
• Keep the connecting wires as short as possible; and
• Keep signal wires away from noise sources.