Objectives: EE 465 Measurements

Measurement is an important tool for engineers. As a student of engineering, You should learn: • what can be measured • what should be measured • what kinds of instruments are used in measurement • why measurements are needed • how measurements are used • how to measure the important quantities in the branch of engineering you are

studyingLearning to measure requires practice, so laboratories and other “hands-on” experiencesare useful. But pay attention also to the measurements you make in everyday life—they can teach you a lot about measurement.

Large engineering projects require many kinds of measurements and generate an enormous amount of data. Professional engineers need a good background in statistics inorder to use that measurement data effectively. You would be well served by includinga statistics course in your studies.

EE 465 Instruments and Measurements

Instrumentation System

Transducer

Power

Conditioning Amplifier Recorder

Data Processor

Controller

CommandGenerator

EngineeringAnalysis

ProcessControl

Transducer

Transducer is an analogue device that converts one form of quantity to another form. Examples: Micro phone: Converts acoustics into

electrical signalsStrain Gage: Converts physical

displacement into electrical

Power Supply

That provides energy to drive the transducer and other related components.Microphone and Strain Gages require DC

power to activate their functioning.All active devices such as Diodes,

Transistors and IC require Power to activate.

Signal conditioner:

These modules are electronic circuits that convert, compensate, or manipulate the transducer-output into measurable signals.

Examples:Wheatstone BridgesFilters

Amplifiers

Mostly the output of the transducers are in the form of weak signals( millivolt): difficult to measure; therefore those are amplified in magnitude using Amplifiers.

Examples:All electrical signals are amplified using

amplifier of variable gains

Recorders

Voltage Measuring devices those could record and display off-line reading of the cumulated values. They could be analogue or digital:Examples:

Scopes …analogue deviceTape RecordersMemories

Data Processor

Device those interpret signals in appropriate form to read:

Example:D/A convert for readable displayA/D convert for computer processingGraphical data converters to display in

x-y forms

Command Generators

Command Generator device generates command to represent any variation in relation to time and therefore proper presentation is made.

Examples:Temperature profile over a day (weather)Pressure profile over a day (weather)

Process Controller

Process Controller accepts both Command and Measured signals and compare to give error signals details if required.

Examples:Error signals are fed back to control or

adjust the output in a feedback systems

Engineering Analysis

Data read-out is analyzed to interpret the system behavior in engineering sense.

Examples:X-rays to state the level of abnormailtyMRI to state tumor dimensionsUltra Sound of organs to state their

abnormality, if there is.

Process control device

Certain electrical device are used as actuators to implement control commands:DC MotorsStepping MortorsSolenoidsMotorized ValvesServo MotorsPositioning Device

DC Motors

Stepping Motors

Step Motor

Types of Solenoids

Pull Solenoids Force is Directed

Back towards Solenoid.

Push Solenoids Force is Directed

AWAY from Solenoid

Types of Solenoids

Rotary Solenoids Apply a Torque over

a range of Rotation.

Every Company has different ways to obtain the rotary motion.

Typical Solenoid Applications Linear Applications

Valve Actuators Latching/Switching Pushing/Pulling Objects

Sorting Shutters

Characteristics Size as Force Limited Stroke Lengths

5/8” is a Long Stroke

Motorized Valves

http://www.sobjoy.com/motorised-valve.swf

Servo Control Valves

Examples:Car BrakesAir-conditioner BoilersWater TanksRobots on dutyAutopilotsUnmanned Airborne Vehicles (UAV)

OT Positioning

Radar Positioning

Positioning Device

Work bench positioning