reort verified

97
PROJECT REPORT ON MEASUREMENT AUTOMATION FOR HF IMPEDANCE STANDARD USING LABVIEW BACHELOR OF TECHNOLOGY (ELECTRONICS AND COMMUNICATION ENGINEERING) Report Submitted By: POWRNIMA G KUMAR :-7210406872

Upload: powrnima-g-kumar

Post on 02-Aug-2015

97 views

Category:

Documents


11 download

TRANSCRIPT

Page 1: Reort Verified

PROJECT REPORT

ON

MEASUREMENT AUTOMATIONFOR

HF IMPEDANCE STANDARD USING LABVIEW

BACHELOR OF TECHNOLOGY

(ELECTRONICS AND COMMUNICATION ENGINEERING)

Report Submitted By:

POWRNIMA G KUMAR :-7210406872

BHUTTA COLLEGE OF ENGINEERING & TECHNOLOGY

LUDHIANA, PUNJAB

Page 2: Reort Verified

Punjab Technical University

ORGANISATION PROFILE

NATIONAL PHYSICAL LABORATORY

The National Physical Laboratory is the premier research laboratory in India in the field of physical

sciences. It has developed core competencies in standards, apex level calibration, engineering materials,

electronic materials, materials characterization, radio and space physics, global change and

environmental studies, low temperature physics, and instrumentation. Established in 1947, it is one of

the oldest laboratories of the Council of Scientific and Industrial Research. Its main activities are :

1. Research and development

2. Consultancy

3. Sponsored and contract research

4. Calibration and testing

 

National Physical Laboratory 2

Page 3: Reort Verified

Punjab Technical University

VISION

Make India prosperous by assisting industries, national and other agencies in their development tasks by

providing precision measurements and calibration. Also, to establish world class science and technology

base and provide decisive edge to problems related to Physics by equipping them with internationally

competitive system and solutions.

The various divisions at NPL are :-

1. Physio Mechanical Standards

The division is responsible to establish, maintain and continually upgrade the national standard of

Measurements related to activities and disseminates the standards by providing the apex level calibration

services to the industry and institutions of the country and thus ensures the traceability to measurements

made by these.

2. Electrical & Electronic Standards

The electrical and electronics standards division of NPLI is in NPLI is involved in the realization,

establishment, maintenance and dissemination of SI unit (Si), primary standard, and national standards

of various electrical, electronic and magnetic parameters.

3. Engineering Materials

The Division of Engineering Materials mainly comprises of Metals & Alloys, Advanced Carbon

Products, Polymeric & Soft Materials and Liquid Crystal groups. The objective of this division is to

develop materials, processes and technologies for components, devices and systems in the above

mentioned areas.

National Physical Laboratory 3

Page 4: Reort Verified

Punjab Technical University

4. Electronic Materials

The Division of Electronic Materials has undertaken R & D work on several types of materials:

electroluminescent, photovoltaic and electro chromic materials, nanostructure materials, high

temperature superconducting materials, advanced ceramic materials and polymeric materials.

5. Materials Characterization

Characterization of various materials being developed at NPL, like thin films, nano tubes, Nano rods,

Nano wires, composite materials for engineering applications, electronic materials for device fabrication

etc. are being carried out regarding their composition, trace impurities, crystalline structure, crystalline

perfection, surfaces & interfaces, at this division regularly as central facility of the laboratory.

6. Radio & Atmospheric Sciences

The activities of the Radio and Atmospheric Sciences Division comprise with two Major Laboratory

projects of the laboratory. The first project is entitled “Radio Physics and Applications”. The second

Major Laboratory Project is entitled “Atmospheric Environment and Global Change”. It also operates

Regional Warning Centre (RWC, NPL-India), an International facility for providing Space Weather

Alerts to the users in the country

7. Superconductivity and Cryogenics

A major activity of the division has been continuation of basic research in doped MgB2 superconductors.

National Physical Laboratory 4

Page 5: Reort Verified

ACKNOWLEDGEMENT

The submission of this project gives me the opportunity to convey my gratitude to all those who have

helped me in the completion of this project. I would like to take this opportunity to thank and

acknowledge Mr. A.K.SAXENA, Scientist F., LH & HF Impedance & DC standards and Mr.

SATISH, Scientist B for his guidance and support, an inspired project in charge for this project without

which my submission would not have been possible.

It has been an enriching experience while working for this project.

POWRNIMA G KUMAR

Page 6: Reort Verified

Punjab Technical University

LIST OF FIGURES

S . NO. FIGURES PAGE No.

1. VI FRONT PANEL 19

2. VI BLOCK DIAGRAM 20

3. LCR CIRUIT 21

4 CIRCUIT BEHAVES AS INDUCTOR 22

5 CIRCUIT BEHAVES AS CAPACITOR 23

6 CIRCUIT BEHAVES AS RESISTOR 24

7 LCR PARALLEL CIRCUIT 25

8 WAYNE KERR 6500P 27

9 WAYNE KERR 6500P INSTRUMENT FRONT PANEL 29

10 OPERATION OVERVIEW 33

11 COMPONENT FIXTURE 34

12 AGILENT E4980A 36

13 AGILENT E4980A INSTRUMENT FRONT PANEL 37

14 OPERATION OVERVIEW 40

15 STANDARD CAPACITORS 44

16 STANDARD INDUCTORS AND RESISTORS 44

17 CONFIGRATION BLOCK 46

18 EXECUTION BLOCK 49

19 WRITING TO SPREADSHEET 52

20 AGILENT E4980A BLOCK DIAGRAM 53

21 AGILENT E4980A FRONT PANEL 54

22 WAYNE KERR6500P BLOCK DIAGRAM 55

23 WAYNE KERR 6500P FRONT PANEL 56

National Physical Laboratory 6

Page 7: Reort Verified

Punjab Technical University

TABLE OF CONTENTS

S. NO. TABLE OF CONTENTS PAGE No.

1 OBJECTIVE 8

2 INSPIRATION 9

3 HARDWARE AND SOFTWARE REQUIREMENTS 10

4 SYSTEM DESCRIPTION 11

5 SYSTEM BLOCK DIAGRAM 53

6 RESULT 57

7 CONCLUSION 65

8 DISCUSSION 66

9 CHALLENGES FACED 67

10 BIBLIOGRAPHY 68

11 APPENDIX 69

National Physical Laboratory 7

Page 8: Reort Verified

Punjab Technical University

OBJECTIVE

The main objective of this project is to automate a LCR meter with the help of a software program. This

is done with the help of LabVIEW . It is a graphical programming language which helps in execution on

the program in a sequential manner. The project is useful as the measurements made are accurate and

unwanted human errors can be dissolved. Automation is extremely important as the measurement time is

considerably reduced and possibilities of errors are significantly low.

National Physical Laboratory 8

Page 9: Reort Verified

Punjab Technical University

INSPIRATION

Graphical programming is relatively new and different from the theoretical languages. Coding with C,

C++ can be tedious and tough at times and also requires a lot of time and effort. So I chose a graphical

language, like LabVIEW which is a extremely user friendly software, more innovative than the basic

languages and is easy to use. In labVIEW troubleshooting is far more easier as compared to any other

programming language. With the help of a program I was able to automate an instrument from which

precise and accurate readings can be measured.

National Physical Laboratory 9

Page 10: Reort Verified

Punjab Technical University

HARDWARE AND SOFTWARE REQUIREMENTS

HARDWARE

Laptop / Desktop

LCR Meter

o Wayne Kerr (6500P)

o Agilent E4980A

Capacitors

GPIB Interface

SOFTWARE

LabVIEW Software

National Physical Laboratory 10

Page 11: Reort Verified

Punjab Technical University

SYSTEM DESCRIPTION

1. AUTOMATION

The creation and application of technology to monitor and control the instrument for delivery of results

is known as automation. Automation encompasses many vital elements, systems, and job functions.

Automation provides benefits to virtually all of industry.

Manufacturing , including food and pharmaceutical, chemical and petroleum, pulp and paper

Transportation , including automotive, aerospace, and rail

Utilities , including water and wastewater, oil and gas, electric power, and telecommunications

Defense

Facility operations , including security, environmental control, energy management, safety, and

other building automation

Automation means Self Dedicated that comes from a Greek  word The automation can be done through

computer numerical control etc. This will help in the reduction of need for human intervention.

Nowadays they became the important source in industries because they produce good quality in low

cost. The control of industrial machines and process with the help of computer by replacing human

operators is known as Industrial Automation

National Physical Laboratory 11

Page 12: Reort Verified

Punjab Technical University

1.1 Features of Automation

The purpose of a measurement automation process is based on the principles of goal-driven

measurement.

Automation plays an increasingly important role in the global economy and in our daily lives. Engineers

strive to combine automated devices with mathematical and organizational tools to create complex

systems for a rapidly expanding range of applications and human activities.

Automation can perform the following functions:

identification of the instrument

configuring the instrument

trigger

calculation of required parameters

report generation

Measurement Automation is the use of control systems and information technologies to reduce the need

for human work in the measurements of parameters of an instrument. Whereas mechanization provided

human operators with machinery to assist them with the muscular requirements of work, automation

greatly decreases the need for human sensory and mental requirements as well. Automation plays an

increasingly important role in the world economy and in daily experience.

National Physical Laboratory 12

Page 13: Reort Verified

Punjab Technical University

1.2 Automation Software

.Although manual tests may find many defects in a software application, it is a laborious and time

consuming process. In addition, it may not be effective in finding certain classes of defects.

Measurement automation is a process of writing a computer program to do testing that would otherwise

need to be done manually. Once tests have been automated, they can be run quickly and repeatedly. This

is often the most cost effective method for software products that have a long maintenance life, because

even minor patches over the lifetime of the application can cause features to break which were working

at an earlier point in time.

There are two general approaches to measurement automation:

Code-driven testing

Graphical user interface testing.

What to automate, when to automate, or even whether one really needs automation are crucial decisions

which the development team must make. Selecting the correct features of the product for automation

largely determines the success of the automation. Automating unstable features or features that are

undergoing changes should be avoided.

Advantages of Automation:

High quality,

Repeatability,

Reduced lead time,

Increase in production,

Cost is reduced.

National Physical Laboratory 13

Page 14: Reort Verified

Punjab Technical University

Some industries have lacking of productivity ratio in their product. However the setup of automation

cost is high, the industries started picking up industrial automation to develop their productivity ratio at

low cost and good quality.

2. LABVIEW SOFTWARE

National Physical Laboratory 14

Page 15: Reort Verified

Punjab Technical University

LabVIEW is a graphical programming language that uses icons instead of lines of text to create

applications. In contrast to text-based programming languages, where instructions determine program

execution, LabVIEW uses dataflow programming, where the flow of data determines execution.

In LabVIEW, you build a user interface with a set of tools and objects. The user interface is known as

the front panel. You then add code using graphical representations of functions to control the front panel

objects. The block diagram contains this code. In some ways, the block diagram resembles a flowchart.

You can purchase several add-on software toolsets for developing specialized applications. All the

toolsets integrate seamlessly in LabVIEW. The design on a VI program minimizes the use of hardware

the automation as it is being carried out with the support of software written in NI LabVIEW

(Laboratory Virtual Instrumentation Engineering Workbench).

2.1 Virtual Instrumentation – Introduction

Virtual Instrumentation uses off-the shelf mainstream computer technologies combined with innovative,

flexible software and modular high-performance hardware technologies to create powerful computer

based instrumentation solutions. The objective in virtual instrumentation is to use a PC to mimic real

instruments with their dedicated controls and displays with the added versatility that come with

software. Virtual Instrumentation combines hardware and software with industrial standard

computerized technologies to create user-defined instrumentation solutions. National Instruments

specializes in developing plug-in, distributed hardware and driver software for data IEEE 488(GPIB),

serial and industrial communications. The driver software is the application programming interface to

the hardware and is consistent across National Instruments application software, such as LabVIEW. This

platform delivers the sophisticated display and analysis capabilities that the Virtual Instrumentation

requires.

National Physical Laboratory 15

Page 16: Reort Verified

Punjab Technical University

Virtual Instrumentation can be used to create a complete and customized system for measurement and

industrial automation by combining different hardware and software components. If there is any upgrade

required in the process the same system can be used with some modifications, there is option of

extending present components for the further use. National Instruments LabVIEW is an industry-leading

software tool for designing test, measurement, and control systems. Since its introduction in 1986,

engineers and scientists worldwide who have relied on NI LabVIEW graphical development for projects

throughout the product design cycle have gained improved quality, shorter time to market, and great

engineering and manufacturing efficiency. By using the integrated LabVIEW environment to interface

with real-world signals, analyze data for meaningful information,. Because LabVIEW has the flexibility

of programming language combined with built-in tools designed specifically for test, measurement and

control.

FUNDAMENTALS OF VIRTUAL INSTRUMENTS

National Physical Laboratory 16

Page 17: Reort Verified

Punjab Technical University

Traditional Instruments Virtual Instruments

Vendor-defined User-defined

Function-specific, stand-alone with limited

connectivity

Application-oriented system with connectivity to

networks, peripherals, and applications

Hardware is the key Software is the key

Expensive Low-cost, reusable

Closed, fixed functionality Open, flexible functionality leveraging off familiar

computer technology

Slow turn on technology (5-10 year life cycle) Fast turn on technology (1-2 year life cycle)

Minimal economics of scale Maximum economics of scale

High development and maintenance

costs

Software minimizes development and

maintenance costs.

Graphical Programming is basically

Easy to use

Fast Development Time

Graphical User Interface

Graphical Source Code

Easily Modularized

Application Builder to create stand-alone executables

National Physical Laboratory 17

Page 18: Reort Verified

Punjab Technical University

2.2 LabVIEW - Ideal for virtual instrumentation

LabVIEW is an integral part of virtual instrumentation because it provides an easy-

to-use application development environment designed specifically for engineers

and scientists .LabVIEW offers powerful features that make it easy to connect to a

wide variety of hardware and other software. This ease of use and these features

deliver the required flexibility for a virtual instrumentation software development

environment. The result is a user-defined interface and user-defined application

functionality. One of the most powerful features that LabVIEW offers is its graphical

programming paradigm. With LabVIEW, we can design custom virtual instruments

by creating a graphical user interface on the computer screen through which they:

Operate the instrumentation program

Control selected hardware

Analyze acquired data

Display results

They can customize the LabVIEW user interface, or front panel, with knobs,

buttons, dials, and graphs to emulate traditional instrument control panels of,

create custom test panels, or visually represent process control and operation.

Determine virtual instrument behavior by connecting icons to create block

diagrams. With graphical programming, we can develop systems more rapidly than

with conventional programming languages, while retaining the power and

flexibility needed to variety of applications. LabVIEW is an open environment that

includes ready-to-use libraries for everything from serial, Ethernet, and GPIB

National Physical Laboratory 18

Page 19: Reort Verified

Punjab Technical University

communication .LabVIEW programs are called virtual instruments, or VIs, because

their appearance and operation imitate physical instruments.

2.3 Basic components in LabVIEW

A VI contains the following two major components:

Front Panel

Block Diagram

2.3.1 VI Front Panel

In the front panel

Controls = Inputs

Indicators = Outputs

National Physical Laboratory 19

Page 20: Reort Verified

Punjab Technical University

VI Front Panel

Front Panel Toolbar

GraphLegend

BooleanControl

WaveformGraph

Icon

PlotLegend

ScaleLegend

FIG 1- VI FRONT PANEL

2.3.2 VI Block Diagram

The block diagram basically has

Components “wired” together

Accompanying “program” for front panel

National Physical Laboratory 20

Page 21: Reort Verified

Punjab Technical University

VI Block Diagram

Wire Data

GraphTerminal

SubVI

While LoopStructure

Block Diagram ToolbarDivideFunction

Numeric Constant

Timing Function

Boolean Control Terminal

FIG 2- VI BLOCK DIAGRAM

3. LCR CIRCUIT (SERIES AND PARALLEL)

3.1 Series Circuit

The circuit contains all the elements namely inductance, capacitance and resistance, as well as their

properties such as Reactance, Phase, Impedance etc. When L C and R are connected together in series

and supplied with an alternating voltage, the same circuit current (I) flows through all the components

of the circuit, and VR VL and VC indicate the voltages across the resistor, the inductor and the capacitor

National Physical Laboratory 21

Page 22: Reort Verified

Punjab Technical University

respectively. In LCR circuits both internal (inductor) resistance, and external resistance are present in

the complete circuit. So it is easier to consider that the voltage VR is the voltage across the TOTAL

circuit resistance, which comprises the internal resistance of L, added to any separate fixed resistor and

VS  is the applied supply voltage. The phase relationship between the supply voltage VS and the circuit

current IS depends on the relative values of inductance and capacitance, and whether the inductive

reactance (XL) is greater or less than the capacitive reactance (XC). There are various conditions

possible, which are illustrated using phasor diagram

FIG 3- LCR SERIES CIRCUIT

National Physical Laboratory 22

Page 23: Reort Verified

Punjab Technical University

FIG 4- CIRCUIT BEHAVES LIKE INDUCTOR

The diagram shows the circuit conditions when the inductive reactance (XL) is greater than the

capacitive reactance (XC). In this case, since both L and C carry the same current, and XL is greater than

XC, it follows that VL must be greater than VC.

(VL = ISXL and VC = ISXC). The VC and VL are in anti-phase to each other due to their 90° leading and

lagging relationship with the circuit current (IS). As VL and VC directly oppose each other, a resulting

voltage is created, which will be the difference between VC and VL. This is called the REACTIVE

VOLTAGE and its value can be calculated by simply subtracting VC from VL. This is by the phasor

(VL − VC).

The length of the phasor (VL − VC) can be arrived at graphically by removing a portion from the tip of

the phasor (VL), equivalent to the length of phasor (VC). VS is therefore the phasor sum of the reactive

voltage (VL − VC) and VR. The phase angle θ shows that the circuit current IS lags on the supply voltage

VS by between 90° and 0°, depending on the relative sizes of (VL − VC) and VR. Because IS lags VS, this

must mean that the circuit is mainly inductive, but the value of inductance has been reduced by the

presence of C. Also the phase difference between IS and VS is no longer 90° as it would be if the circuit

consisted of only pure inductance and resistance.

National Physical Laboratory 23

Page 24: Reort Verified

Punjab Technical University

FIG 5- CIRCUIT BEHAVES AS CAPACITOR

This diagram illustrates the phasor diagram for a LCR series circuit in which XC is greater than

XL showing that when VC exceeds VL 

The resultant reactive voltage is now given by (VC − VL) and VS is the phasor sum of (VC − VL) and

VR.

The phase angle θ now shows that the circuit current (IS) leads supply voltage (VS) by between 0° and

90°. The overall circuit is now capacitive, but less so than if L was not present.Looking at the phasor

diagrams for a LCR series circuit it can be seen that the supply voltage (VS) can either lead or lag the

supply current(IS) depending largely on the relative values of the component reactance’s, XL and XC.

National Physical Laboratory 24

Page 25: Reort Verified

Punjab Technical University

FIG 6- CIRCUIT BEHAVES AS RESISTOR

The diagram shows the situation, which must occur at some particular frequency, when XC and XL (and

therefore VC and VL) are equal.

The opposing and equal voltages VC and VL now completely cancel each other out. The supply voltage

and the circuit current must now be in phase, so the circuit is apparently entirely resistive! L and C have

completely "disappeared".

3.2 Parallel Circuit

The circuit in is an "Ideal" LC circuit consisting of only an inductor L and a capacitor C connected in

parallel. Ideal circuits exist in theory only, but their use makes understanding of basic concepts easier. It

allows consideration of the effects of L and C, ignoring any circuit resistance that would be present in a

practical circuit.

In phasor diagrams for the circuit , under three different conditions are below, above and at resonance.

Unlike the phasor diagrams for series circuits, these diagrams have a voltage VS as the reference

(horizontal) phasor, and have several phasors depicting currents. This is because, in a parallel circuit the

voltage VS is common to both the L and C arms of the circuit and each of the component arms (L and C)

can have individual Currents

National Physical Laboratory 25

Page 26: Reort Verified

Punjab Technical University

The phasors for L and C seem to be reversed compared with the phasor diagrams for series circuits, but

the parallel phasor diagram shows the current IC through the capacitor leading the supply voltage VS by

90°, while the inductive current IL lags the supply voltage by 90°.

FIG 7- LCR PARRALEL CIRCUIT

The supply current IS will be the phasor sum of IC and IL but as, in the ideal circuit, there is no

resistance present, IC and IL are exactly in anti phase, and IS will be simply

National Physical Laboratory 26

Page 27: Reort Verified

Punjab Technical University

the difference between them. the circuit operating at some frequency below resonance ƒ r where IL is

greater than IC and the total current through the circuit IS is given by IL − IC and will be in phase with IL,

and it will be lagging the supply voltage by 90°. Therefore at frequencies below ƒr more current flows

through L than through C and so the parallel circuit acts as an INDUCTOR.. When XC will be lower

than XL more current will flow through C. IC is therefore greater than IL and as a result, the total circuit

current IS can be given as IL − IC but this time IS is in phase with IC. The circuit is now acting as a

CAPACITOR.

At resonance (ƒr) the reactance’s of C and L will be equal, so an equal amount of current flows in each

arm of the circuit, (IC = IL). This produces a very strange condition. Considerable current is flowing in

each arm of the circuit, but the supply current is ZERO. This impossible state of affairs of having

currents flowing around the circuit with no supply current, indicates that the circuit must have infinite

impedance to the supply. As there is no resistance in either L or C in the ideal circuit, current continues

to flow from L to C and back again. This only happens of course in an ideal circuit, due to the complete

absence of resistance in either arm of the circuit.

National Physical Laboratory 27

Page 28: Reort Verified

Punjab Technical University

4. LCR METER

The LCR meter can be used to measure the various parameters used in

measurement.

WAYNE KERR 6500P

AGILENT E4980A

4.1 WAYNE KERR 6500P LCR METER

FIG 8-WAYNE KERR 6500P

The 6500P series of High Frequency LCR Meters provides impedance measurement

capability of components from 20Hz up to 120MHz. A comprehensive range of

functions enables a component to be accurately characterized over a wide

frequency range. The Graphical User Interface (GUI) combined with the large touch

screen TFT display enables measurement parameters to be modified easily and

National Physical Laboratory 28

Page 29: Reort Verified

Punjab Technical University

quickly. The instruments may be remotely controlled using the GPIB or LAN

interface

4.1.1 Measurement Parameters

A comprehensive range of AC functions enables a wide range of components to be accurately

characterized. Each measurement displays two user selectable component parameters, which allow

specific component characteristics to be monitored.

Capacitance (C)

Inductance (L)

Resistance (R)

Reactance (X)

Conductance (G)

Susceptance (B)

Dissipation Factor (D)

Quality Factor (Q)

Impedance (Z)

Admittance (Y)

Phase Angle (Ø)

All the above functions can be selected via manual front panel control or controlled remotely via the

GPIB or LAN interfaces for fully-automated high-speed testing.

National Physical Laboratory 29

Page 30: Reort Verified

Punjab Technical University

4.1.2Front Panel

FIG 9 -FRONT PANEL

1) Switching the Instrument ON

When the instrument is connected to the correct AC power supply, press the POWER switch. The

power indicator will light, the bias indicator will flash and after running the start up routine the

instrument will display Meter Mode.

2) Switching the Instrument OFF

The power can be switched OFF at any time without damage to the instrument, but to avoid losing trim

and calibration data, the instrument should be switched OFF when it is in a quiescent state rather than

when it is running a routine, e.g. trimming, calibration or data entry.

National Physical Laboratory 30

Page 31: Reort Verified

Punjab Technical University

3) Touch Panel Interface

The instrument should always be controlled using the LCD display touch panel interface.

the stylus supplied to select instrument modes, functions and measurement parameters. The parameter

to be modified is done by lightly touching the LCD screen with the point of the stylus and the screen

will respond by displaying the new setting.

The item selected by the stylus only becomes active when the stylus is lifted off the touch

screen.

4) The Navigation Keys

The navigation keys can be used in place of the touch screen display or mouse to

move around the screen.

5) Measurement Keys

6) Trigger

When in single shot mode, the Trigger key initiates a single measurement. If it is pressed and held, the

analyzer will continue to make measurements until the key is released.

5) Bias

The Bias key applies DC bias to the AC measurement signal if a DC bias option (/D1) is fitted.

National Physical Laboratory 31

Page 32: Reort Verified

Punjab Technical University

6) Control Keys

7) Menu

Displays or hides the File, Mode or Display menu items.

8) Tab

It selects the next menu, test parameter or option.

Deletes the last entered character when the screen data input keypad is displayed.

9) F1 and F2

Menu specific functions

10) Enter

Confirm data entry when the screen data input keypad is displayed.

11) Save

Saves the instrument set-up.

12) Help

National Physical Laboratory 32

Page 33: Reort Verified

Punjab Technical University

Displays the instrument type and the software revision instrument

13) Local

Restores control to the front panel when the instrument is under external (GPIB) control.

14) Data Entry Keypad

National Physical Laboratory 33

Page 34: Reort Verified

Punjab Technical University

4.1.3 Operation Overview

The 6500P series of High Frequency LCR Meters features a touch screen display which enables the

instrument to be controlled by selecting menu items, measurement parameters and control functions

directly from the displayed image. It is recommended that a stylus always be used when controlling the

instrument using the touch screen interface. Alternatively the instrument may be controlled using the

front panel keypad or external keyboard and /or mouse. The settings can be saved independently using

the Save command from the File drop-down menu These settings can then be recalled using the Load

command from the File

FIG 10- FRONT PANEL OVERVIEW

National Physical Laboratory 34

Page 35: Reort Verified

Punjab Technical University

4.1.4 Measuring a Component

1) Component Fixture

FIG 11- COMPONENT FIXTURE

2) Measurement Parameters

Any of the following parameters can be measured and displayed.

3) AC Functions

Capacitance (C), Inductance (L), Resistance (R), Reactance (X), Conductance (G), Susceptance (B),

Dissipation Factor (D), Quality Factor (Q), Impedance (Z),

Admittance (Y) and Phase Angle ().

4) Equivalent Circuit

Series or Parallel.

National Physical Laboratory 35

Page 36: Reort Verified

Punjab Technical University

5) Test Conditions

Frequency Range

65120P

20Hz to 120MHz

6) Specification

Measurement Range

G,Y,B 0.01nS to >2kS

L 0.1nh to > 2kH

C 1Ff to >1F

R, Z, X 0.01mohm to >2Gohm

Q 0.00001 to >1000

D 0.00001 to >1000

Measurement accuracy

Dissipation factor

±0.0005 (1+D2)**

Quality factor

±0.05 %( Q+1/Q)**

Capacitance / Inductance / Impedance

±0.05%

***Varies with frequency, drive level and measured impedance

7) AC Drive

National Physical Laboratory 36

Page 37: Reort Verified

Punjab Technical University

Drive Level (AC Measurements)

4.2 AGILENT E4980A

FIG 12-AGILENT E4980A

The Agilent E4980A is a general-purpose LCR meter for incoming inspection of components, quality

control, and laboratory use. The E4980A is used for evaluating LCR

components, materials, and semiconductor devices over a wide range of frequencies (20

Hz to 20 MHz) and test signal levels (0.1 mVrms to 2 Vrms, 50 μA to 20 mArms).

The E4980A’s test signal level range spans 0.1 mV to 20 Vrms, and 50 μA to 200 mArms The E4980A

offers C-D measurement with a basic accuracy of ±0.05% (C), ±0.0005 (D) at all frequencies with

seven-digit resolution (the dissipation factor resolution is 1 ppm) in every range.. The E4980A can be

easily combined with a component handler, a scanner, and a system controller to fully automate

component testing, sorting, and quality-control data processing. The E4980A’s list sweep function

permits entry of up to 201 frequencies, test signal levels, or bias level points to be automatically

National Physical Laboratory 37

Page 38: Reort Verified

Punjab Technical University

measured. The GP-IB/LAN/USB interfaces are standard interfaces on the E4980A and enable automatic

testing.

4.2.1 Front Panel

This section describes the names and functions of the parts on the E4980A’s front panel.

FIG13- FRONT PANEL

1) Power switch

Used for choosing between power-on and -off states of the E4980A. When turned on, the

switch lights up in yellow-green and all operating voltages are applied to the instrument.

When turned off, the switch lights up in orange and no operating voltages are applied to the instrument.

2) LCD

The Liquid Crystal Display (LCD) displays measurement results, test conditions, etc.

National Physical Laboratory 38

Page 39: Reort Verified

Punjab Technical University

Occasionally there are missing pixels or constantly lit pixels, but this is not a malfunction and does not

affect the performance of the instrument.

3) Soft keys

Five soft keys are used to select measurement conditions and parameter functions. Each Soft key has a

soft key label along its left side.

4) Menu keys

Menu selection keys are used to access the corresponding selection of instrument controls.

5) Cursor keys

These keys used to move the field select cursor from field to field on a displayed page. When the cursor

is moved to a certain field, that field changes to an inverse video image of the original field. The cursor

can only be moved from field to field.

6) Entry keys

These keys are used to enter numeric data into the E4980A. The entry keys comprise the digits 0 to9, a

period (.), and a plus/minus (+/-) sign. Entered values are displayed on the input line(second line from

the bottom of the LCD screen), and pressing the softkey terminatesnumeric input. The plus/minus key

deletes the last character of the input value.

7) LED indicator

The LED indicator lights up when DC Bias or DC Source is on. The USB indicator lights

up while accessing a USB memory.

8) Preset key

A key used to return the LCR meter to the initial setup state

9) Trigger key

A key used to manually trigger the E4980A when it is set to the manual trigger mode.

National Physical Laboratory 39

Page 40: Reort Verified

Punjab Technical University

10) DC Bias key

This key is used to toggle on and off of the DC bias output. When the DC bias output is set to on, the

DC bias indicator lights up and DC BIAS is displayed in the status display area on the screen. If the DC

Bias key is set to off, even though the DC bias is set to on according to the LCD display, the DC bias is

not output. Regardless of which page is displayed, when the DC BIAS key is pressed, the value that has

been set in the BIAS field of MEAS SETUP (and MEAS DISPLAY) is output

11) DC Source key

This key is used to toggle on and off of the DC source output. When the DC source output is set to on,

the DC Source indicator lights up and DC SRC is displayed in the status display area screen. Regardless

of which page is displayed, when the DC SOURCE key is pressed, the value that has been set in the DC

SRC field of MEAS SETUP is output.

12) UNKNOWN terminals

These are the UNKNOWN terminals used to connect a four-terminal pair test fixture or test leads for

measuring the device under test (DUT).

13) Front USB port

This port is used to save data in a USB memory. The USB indicator lights up while

accessing the USB memory.

14) USB memory type

USB memory is used for USB mass-storage-class compliant and format.

15) Frame terminal

This is used for measurements that require guarding.

16) DC Source terminal

Outputs the DC source in the range from -10 V to 10 V. Option 001 is required for this.

National Physical Laboratory 40

Page 41: Reort Verified

Punjab Technical University

4.2.2 Operation Overview

Screen Area: Names and Functions of Parts

FIG 14- FRONT PANEL OVERVIEW

1) Display Page Area

Shows a display page name of the current display page. On each display page, three lines

are collected together as one area.

2) Comment Line Area

The input is up to 30 characters in ASCII format by using the front panel or the

Display: LINE command of the GPIB command. The first 22 characters are displayed in

this area.

This area is displayed on the following display pages.

MEAS DISPLAY page

BIN No. DISPLAY page

National Physical Laboratory 41

Page 42: Reort Verified

Punjab Technical University

BIN COUNT DISPLAY page

LIST SWEEP DISPLAY page

MEAS SETUP page

3) Soft key Area

This displays the soft key labels corresponding to the field.

A display to the right of a soft key indicates that pressing that soft key will display the

soft key label one level lower

4) Measurement Data/Conditions Area

It displays measurement conditions and measurement results.

Under certain conditions one of the following messages may be displayed instead of the

measurement results.

5) Input Line Area

This displays numeric values entered with the entry key.

6) System Message Area

This displays a system message, warning, and error message.

7) Status Display Area

This displays the status when DC bias or DC source is on, or any front panel key is locked. When

sending SCPI commands from the external controller, “RMT” is displayed and the front panel keys are

locked.

National Physical Laboratory 42

Page 43: Reort Verified

Punjab Technical University

4.2.3 Measurement parameter descriptions

Primary parameter

Cp - Capacitance value measured using the parallel equivalent circuit model

Cs - Capacitance value measured using the series equivalent circuit model

Lp - Inductance value measured using the parallel equivalent circuit model

Ls - Inductance value measured using the series equivalent circuit model

R - Resistance

Z - Absolute value of impedance

G - Conductance

Y - Absolute value of admittance

Secondary parameter

D - Dissipation factor

Q - Quality factor (inverse of dissipation factor)

G - Conductance

Rs - Equivalent series resistance measured using the series equivalent circuit model

Rp - Equivalent parallel resistance measured using the parallel equivalent circuit model

X - Reactance

B - Sustenance

Θ - Phase angle

National Physical Laboratory 43

Page 44: Reort Verified

Punjab Technical University

4.2.4 Equivalent parallel and serial combinations

PRIMARYFACTOR

SERIES MODE PARALLEL MODE

Z Z-θr

Z-θd

-------

Y --------- Y-θr

Y-θd

C Cs-D

Cs-Q

Cs-Rs

Cp-D

Cp-Q

Cp-G

Cp-Rp

L Ls-D

Ls-Q

Ls-Rs

Ls-Rdc

Lp-D

Lp-Q

Lp-G

Lp-Rp

Lp-Rdc

R R-X ---------

G ---------- G-B

National Physical Laboratory 44

Page 45: Reort Verified

Punjab Technical University

5. OTHER REQUIREMENTS

5.1 DUC (Device Under Calibration)

This includes standard Capacitors, Resistors and Inductors.

FIG 15-STANDARD CAPACITORS

FIG 16-STANDARD RESISTORS AND INDUCTORS

National Physical Laboratory 45

Page 46: Reort Verified

Punjab Technical University

6. GPIB  

6.1 Introduction

Hewlett-Packard designed the Hewlett-Packard Interface Bus ( HP-IB ) to connect

their line of programmable instruments to their computers. Because of its high

transfer rates (nominally 1 Mbytes/s), this interface bus quickly gained popularity.

It was later accepted as IEEE Standard 488-1975, and has evolved to ANSI/IEEE

Standard 488.1-1987. Today, the name General Purpose Interface Bus (GPIB) is

more widely used than HP-IB. Standard Commands for Programmable Instruments

(SCPI ) took the command structures defined in IEEE 488.2 and created a single,

comprehensive programming command set that is used with any SCPI instrument.

National Physical Laboratory 46

Page 47: Reort Verified

Punjab Technical University

7. AUTOMATION PROGRAM (AGILENT E4980A)

The Automation Program for Agilent E4980A can be studied under three stages

Configuration Block

Execution Block

Writing data into spreadsheet

7.1 Configuration Block

FIG 17-CONFIGRATION BLOCK

National Physical Laboratory 47

Page 48: Reort Verified

Punjab Technical University

The Configuration Block includes various input parameters which are required to feed before

Measurements. It is required (i) to select the Parameter, (ii) to define the input frequency (iii) Meter

speed is either slow, fast or medium etc.(iv) DUC value etc.

7.1.1 VISA

The start of a program is done by a VISA resources. VISA is an object-oriented language. The most

important objects in the VISA languageare known as resources. In object-oriented terminology, the

functions that can be used with an object are known as operations. In addition to the operations that can

be used with an object, the object has variables associated with it that contain information related to the

object. In VISA, these variables are known as attributes.

1) VISA Resource name

Visa resource name specifies the resource to be opened .The visa resource name control also

specifies session and the class. If duplicate session is TRUE and there is currently a session opened to

the resource, another session is opened to the resource. If duplicate session is set to FALSE and a

session is opened to the resource, the open session is used. A VISA session is a unique logical identifier

used by VISA to communicate with a resource. Error in (no error) describes error conditions that

occur before this node runs .This input provides standard error in functionality.

VISA resource name out is the resource to which a VISA session is opened and its class. The class

matches that of the VISA resource name input .Error out contains error information This output

provides standard error out functionality’

2) VISA Open

It is used to open sessions to the resources in the system using the Default Resource Managers ability to

open sessions. The VISA Open VI that carries

National Physical Laboratory 48

Page 49: Reort Verified

Punjab Technical University

out this operation is shown below.

The resource name input is the VISA instrument descriptor for the resource to which a session will be

opened..

3) VISA Write and Read

A user only needs to know that they would like to write a message or read a message from a message-

based device. The VI’s that are used to perform these operations are VISA Write and VISA Read

The Write VI is shown below

The only input, besides the instrument session, is the string to be sent to the instrument.

The VISA Read VI is equally easy to use. It is shown below

National Physical Laboratory 49

Page 50: Reort Verified

Punjab Technical University

7.1.2 Pick line function

Chooses a line from multi-line string and appends that line to string. The connector pane displays the

default data types for this polymorphic function.

7.2 Execution Block

FIG 18- EXECUTION BLOCK

National Physical Laboratory 50

Page 51: Reort Verified

Punjab Technical University

The Execution unit basically executes the data. It includes For loop function, Scan from string function,

VISA Write, Strings, Mean Variance and Standard Deviation function etc.

7.2.1 For Loop

Executes its subdiagram n times, where n is the value wired to the count (N) terminal. The iteration (i)

terminal provides the current loop iteration count, which ranges from 0 to n-1.

7.2.2 Scan From String Function

Scans the input string and converts the string according to format string.Use this function when

you know the exact format of the input. The input can be string path, enumerated type, time

stamp, or numeric data

7.2.3 Format Into String

Increase the number of parameters by right-clicking the function and selecting Add Parameter from the

shortcut menu or by resizing the function.If you wire a block diagram constant string to format string,

LabVIEW uses format string to determine the number of outputs and the data type of each output at

compile time.

National Physical Laboratory 51

Page 52: Reort Verified

Punjab Technical University

7.2.4 Standard Deviation and Variance VI

Computes the mean, standard deviation, and variance of the values in the input sequence. Mean is the

mean or average of the values of x.

Standard deviation is the standard deviation calculated from the values in the input sequence x

Variance is the calculated variance of the values in the input sequence x

National Physical Laboratory 52

Page 53: Reort Verified

Punjab Technical University

7.3 Writing into Spreadsheet

FIG 18- WRITING TO SPREADSHEET

7.3.2 Writing into spreadsheet

Data can be transferred into spreadsheet with the help of Microsoft office tools box present in

LabVIEW. automatically data can be incurred with its help.

7.3.3 MS Office Report

This function is used to measure the output readings ,and can be used to plot graphs

National Physical Laboratory 53

Page 54: Reort Verified

Punjab Technical University

SYSTEM BLOCK DIAGRAM

AGILENT E4980A

Block Diagram

FIG 20-AGILENT E4980A BLOCK DIAGRAM

National Physical Laboratory 54

Page 55: Reort Verified

Punjab Technical University

Front Panel

FIG 21-AGILENT E4980A FRONT PANEL

National Physical Laboratory 55

Page 56: Reort Verified

Punjab Technical University

WAYNE KERR 6500P

Block Diagram

FIG 22-WAYNEE KERR 6500P BLOCK DIAGRAM

National Physical Laboratory 56

Page 57: Reort Verified

Punjab Technical University

Front Panel

FIG 23- WAYNE KERR 6500P FRONT PANEL

National Physical Laboratory 57

Page 58: Reort Verified

Punjab Technical University

RESULT

The LCR meter is being successfully automated with the help of LabVIEW program and the

measurements of various capacitors at different frequencies are as follows:-

CAPACITANCE 1pF ±0.1%

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 9.41074E-13 9.50512E-13 1.07052E-12 8.50415E-13 9.45594E-13 9.45594E-13 7.83078E-14

500 1.00240E-12 1.00524E-12 1.00592E-12 1.00592E-12 1.00389E-12 1.00389E-12 1.39175E-15

1000 9.96398E-13 9.97026E-13 9.96868E-13 9.95843E-13 9.94982E-13 9.94982E-13 8.33058E-16

Reference value

Frequency (Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5

100 0.94107 0.95051 0.95051 0.95051 0.95051

500 1.00240 1.00524 1.00592 1.00359 1.00389

1000 0.99640 0.99703 0.99687 0.99584 0.99498

DISSIPATION FACTOR

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 9.41074E-13 9.50512E-13 1.07052E-12 8.50415E-13 9.45594E-13 9.51623E-13 7.83078E-14

500 1.00240E-12 1.00524E-12 1.00592E-12 1.00359E-12 1.00389E-12 1.00421E-12 1.39175E-15

1000 9.96398E-13 9.97026E-13 9.96868E-13 9.95843E-13 9.94982E-13 9.96223E-13 8.33058E-16

National Physical Laboratory 58

Page 59: Reort Verified

Punjab Technical University

CAPACITANCE 1pF±0.1% GRAPH

National Physical Laboratory 59

Page 60: Reort Verified

Punjab Technical University

CAPACITANCE 10pF ±0.1%

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 9.99770E-12 1.00000E-11 9.99921E-12 9.99786E-12 9.99786E-12 9.99879E-12 9.82538E-16

500 9.99961E-12 9.98993E-12 1.00001E-11 9.99696E-12 9.99951E-12 9.99722E-12 4.25624E-15

1000 9.91606E-12 9.95310E-12 9.95928E-12 9.92436E-12 9.93382E-12 9.93732E-12 9.93732E-12

Reference value

Frequency (Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5

100 9.99770 10.00000 9.99921 9.99786 9.99786

500 9.99961 9.98993 10.00010 9.99696 9.99951

1000 9.91606 9.95310 9.95928 9.92436 9.93382

DISSIPATION FACTOR

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 5.17100E-03 5.03200E-03 -1.34200E-03 4.19300E-03 -3.73700E-03 1.86318E-03 4.12466E-03

500 -3.58000E-04 -1.44021E-05 3.45000E-04 1.79000E-04 -3.56804E-05 -3.56804E-05 3.09050E-04

1000 -2.59000E-04 -4.94817E-05 9.58503E-05 6.87028E-05 -6.81141E-05 -4.24101E-05 1.40612E-04

National Physical Laboratory 60

Page 61: Reort Verified

Punjab Technical University

CAPACITANCE 10pF ±0.1% GRAPH

National Physical Laboratory 61

Page 62: Reort Verified

Punjab Technical University

CAPACITANCE 100pF ±0.1%

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 1.00004E-10 9.99198E-11 9.99510E-11 9.99622E-11 9.99929E-11 9.99660E-11 3.36953E-14

500 9.99956E-11 9.99955E-11 9.99934E-11 1.00001E-10 1.00003E-10 9.99977E-11 4.08412E-15

1000 1.00003E-10 1.00000E-10 1.00002E-10 1.00001E-10 1.00002E-10 1.00002E-10 1.14018E-15

Reference value

Frequency (Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5

100 100.00400 99.91980 99.95100 99.96220 99.99290

500 99.99560 99.99550 99.99340 100.00100 100.00300

1000 100.00300 100.00000 100.00200 100.00100 100.00200

DISSIPATION FACTOR

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 2.60000E-04 3.44000E-04 4.53000E-04 6.88000E-04 4.46000E-04 4.38185E-04 1.60413E-04

500 -6.80697E-06 2.42678E-05 1.90749E-05 2.87915E-05 2.24595E-05 1.75574E-05 1.40641E-05

1000 -8.05317E-06 3.31450E-05 1.90275E-05 -1.84138E-05 2.26853E-05 9.67817E-06 2.18566E-05

National Physical Laboratory 62

Page 63: Reort Verified

Punjab Technical University

CAPACITANCE 100pF ±0.1% GRAPH

National Physical Laboratory 63

Page 64: Reort Verified

Punjab Technical University

CAPACITANCE 1000pF ±0.1%

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 1.00047E-09 1.00045E-09 1.00046E-09 1.00044E-09 1.00062E-09 1.00062E-09 2.70185E-14

500 1.00061E-09 1.00061E-09 1.00062E-09 1.00044E-09 1.00061E-09 1.00061E-09 4.47214E-15

1000 1.00062E-09 1.00062E-09 1.00062E-09 1.00062E-09 1.00062E-09 1.00062E-09 5.47723E-15

Reference value

Frequency (Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5

100 1000.47000 1000.45000 1000.46000 1000.44000 1000.40000

500 1000.61000 1000.61000 1000.62000 1000.61000 1000.61000

1000 1000.62000 1000.62000 1000.62000 1000.62000 1000.62000

DISSIPATION FACTOR

Frequency

(Hz)

Reading 1 Reading 2 Reading 3 Reading 4 Reading 5 MEAN S.D

100 5.12067E-05 3.36443E-05 3.51515E-05 1.15854E-05 5.95891E-05 3.82354E-05 1.84733E-05

500 1.26927E-05 1.25142E-05 1.25142E-05 1.56031E-05 1.06894E-05 1.22299E-05 2.27502E-06

1000 1.70348E-05 2.13549E-05 2.13549E-05 1.77817E-05 1.72866E-05 1.89871E-05 2.23407E-06

National Physical Laboratory 64

Page 65: Reort Verified

Punjab Technical University

CAPACITANCE 1000pF ±0.1% GRAPH

National Physical Laboratory 65

Page 66: Reort Verified

Punjab Technical University

CONCLUSION

This project has been a step towards automating the whole process involved in the calibration of LCR

Meter. It helps to automate the entire process and has been a successful step towards the creation of a

friendly environment while working with the LCR meter. It is not only easy to understand for a person

but also very user friendly.

The time required by the program can be further reduced if more efficient or say, fast detectors could be

used. In that case only the delays of the program need to be eliminated out. There are further more

possibilities which can be include in this program

National Physical Laboratory 66

Page 67: Reort Verified

Punjab Technical University

DISCUSSION

I started this project by building small programs in LabVIEW, then moved on to basic program of LCR

meter which was implemented on Wayne Kerr 6500 LCR meter, and then with further modification and

improvement in the program I was able to make a program to automate the instrument. This program

with further enhancement was used for automation of Agilent E4980A LCR meter as well with which I

measured various capacitors at different frequencies.

National Physical Laboratory 67

Page 68: Reort Verified

Punjab Technical University

CHALLENGES FACED

Even if the code that was syntactically correct and functionally complete, there would be errors due to

data loss or difference in string formats In this project identifying the source and fixing the cause of

unexpected or undesirable software errors was tedious and time-consuming. Highlighted execution

plays a major role in identifying the source of error as the program gets stopped and can be mended at

that point, for successful running of data.

National Physical Laboratory 68

Page 69: Reort Verified

Punjab Technical University

BIBLIOGRAPHY

www.google.com

www.ni.com

National Instruments LabVIEW manual

Wayne Kerr 6500P manual

Agilent E4980A manual

National Physical Laboratory 69

Page 70: Reort Verified

Punjab Technical University

APPENDIX

PARAMETERS OF LCR METER

1) INDUCTANCE

Inductance is the property of an electrical circuit causing voltage to be generated proportional to the rate

of change in current in a circuit. This property also is called self inductance to discriminate it

from mutual inductance, describing the voltage induced in one electrical circuit by the rate of change of

the electric current in another circuit.

The quantitative definition of the self inductance L of an electrical circuit in SI units (Webbers per

ampere, known as henries) 

2) CAPACITANCE

Capacitance is the ability of a body to hold an electrical charge. Capacitance is also a measure of the

amount of electrical energy stored (or separated) for a given electric potential. 

The SI unit of capacitance is the farad; 1 farad is 1 coulomb per volt.

3) RESISTANCE AND CONDUCTANCE

The electrical resistance of an electrical element measures its opposition to the passage of an electric

current; the inverse quantity is electrical conductance, measuring how easily electricity flows along a

certain path. Electrical resistance shares some conceptual parallels with the mechanical notion

of friction. The SI unit of electrical resistance is the ohm (Ω), while electrical conductance is measured

in Siemens (S).

National Physical Laboratory 70

Page 71: Reort Verified

Punjab Technical University

4) IMPEDANCE

Electrical impedance, or simply impedance, describes a measure of opposition to alternating

current (AC). Electrical impedance extends the concept of resistance to AC circuits, describing not only

the relative amplitudes of the voltage and current, but also the relative phases. The symbol for

impedance is usually   and it may be represented by writing its magnitude and phase in the form   .

5) REACTANCE

Reactance is the opposition of a circuit element to a change of electric current or voltage, due to

element's capacitance or inductance. A built-up electric field resists the change of voltage on the

element, while a magnetic field resists the change of current

6) SUSCEPTANCE

 Susceptance (B) is the imaginary part of admittance. The inverse of admittance is impedance and the

real part of admittance is conductance. In SI units, susceptance is measured in Siemens.

7) QUALITY FACTOR

the quality factor or Q factor is a dimensionless parameter that describes how under-

damped an oscillator or resonator

8) DISSIPATION FACTOR

 the dissipation factor (DF) is a measure of loss-rate of power of a mode of oscillation (mechanical,

electrical, or electromechanical) in a dissipative system. It is the reciprocal of Quality factor, 

National Physical Laboratory 71

Page 72: Reort Verified

Punjab Technical University

1) MEASUREMENT

It is an act of a quantitative comparison between a predefined standard and the unknown magnitude of a

physical quantity.

It is essential that the measuring instruments should be calibrated against more accurate and traceable

measurement standards using specified calibration procedures.

2) CALIBRATION

Calibration is a process of verifying the operational integrity of test and measuring equipment or

measuring standards of unverified accuracy by comparing them to the standards of verified (known)

greater accuracy in order to detect, co-relate report or eliminate by adjustment any deviation in accuracy,

capability or from any other required performance. Simply, it is a process in which the equipment under

test or use is compared with standard equipment.

3) ADVANTAGE OF CALIBRATION

a) It enables us to achieve accuracy, precision and interchangeability.

b) It enhances the confidence for use of measurement by knowing the uncertainties associated with

them.

c) It fulfills the requirement of traceability to National Standards.

4) TRACEABILITY

Traceability is the ability to relate measurements back to known “National Standards” through an

unbroken chain of comparison.

National Physical Laboratory 72

Page 73: Reort Verified

Punjab Technical University

5) STANDARD

A standard is a physical device having stable, precisely defined characteristics, that is used as a

reference for a unit of measurement or a physical device, which maintain a unit of some physical

quantity, is called standard of that physical quantity.

Its characteristics are:

a) Stability

b) Accuracy

c) Reliable

d) Insensitive to change in environmental conditions.

e) Reasonable price.

f) Simplicity in construction and use.

6) PRECISION (REPEATABILITY)

The closeness of agreement between results of successive measurements of the same value of a quantity

carried out under identical conditions in a short interval is known as precision. It is used to characterize

the random error. The term Repeatability can be defined as the ability of the instrument to reproduce a

group of measurements of the same measured quantity, made by the same observer, using the same

instrument and under same conditions.

S, known as Precision index of data available, quantifies precision. A large precision index means a lot

of scatter in data and conversely a small precision index means high precision.

7) ACCURACY

Accuracy of a measuring system is defined as the degree of closeness to the true value of quantity under

measurement. It mainly depends on the inherent limitations of the device.

8) UNCERTAINTY

National Physical Laboratory 73

Page 74: Reort Verified

Punjab Technical University

8.1 Introduction

There is no such thing as a perfect measurement! All measurements have errors and uncertainties, no

matter how hard we might try to minimize them.

Hence, a statement of results of measurement is complete only it contains both the values attributed to

the measurand and the uncertainty in measurement associated with that value. Without such an

indication, measured results cannot be compared, either among themselves or with reference values

given in a specification or standard.

8.2 Uncertainty

The uncertainty of measurement is a parameter, associated with the result of a measurement that

characterizes the dispersion of the true value, which could reasonably be attributed to the measurand.

It is a statement of the limits of the range within which the true value of a measurement is expected to lie

in relation to recorded result and it must include the probability of the true value lying within these

limits. This probability is termed as confidence level.

8.3 Sources of Uncertainties

The uncertainty of the result of a measurement reflects the lack of complete knowledge of the value of

the measurand. Complete knowledge requires an infinite amount of information. Uncertainty in a

measurement can arise from mainly three possible origins: the measuring device, the procedure of how

you measure, and the observed quantity itself. Both systematic and random errors affecting the observed

results contribute to the uncertainty. These contributions have been referred to as systematic and random

components of uncertainty respectively. Nowadays, uncertainty is evaluated according to either a “Type

A” or a “Type B” method of evaluation. There are many possible sources of uncertainty in a

measurement, which could be as follows:

Incomplete definition of the measurand;

National Physical Laboratory 74

Page 75: Reort Verified

Punjab Technical University

Non-representative sampling- the sample measured may not represent the defined measurand;

Inadequately known effects of environmental conditions;

Inexact values of measurement standards;

Inexact values of constants and other parameters obtained from external sources and used in

data-reduction algorithm;

Approximations and assumptions incorporated in the measurement method;

National Physical Laboratory 75