Automation Module 01

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Automation Module7 th May 2008

EFC,Pune


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Who are We?

Steven Laycock is Unilevers Technology Leader for process control andautomation. Steve has worked within Unilever since 1996, initially in the Leedssourcing unit and now in the Unilever Europe and Global engineering teams.

Stuart Dow has been with Haden Freeman Ltd, an engineering design andconsultancy company, for 13 years as an EC&I engineer, manager and nowsystems development manager working on projects in a variety of industrysectors.

Karam Rehani is with Hindustan Unilever for the last 27 years .First 13years with factories mfg soaps,detergents,personal products & chemicals.For

last 14 years as Head of Instrumentation & Controls with corporateengineering.supporting businesses & projects on C & Automation.Befor joining Unilever, worked for 9 Yrs with Leading fertiliser cos in India


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Agenda

Module 1:

Basic building blocks used in control & automation

Module 2:

Automation Lifecycles and Industry Standards

Case Studies :

Automation of Tooth Paste Plant at HULLow Cost Batching Solution

Multiple Choice Questionnaire.


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Introduction

What are we going to cover today

3 key areas

-Understanding the cause and use of control systems

Innovation Projects Marketing ledMaintaining equipment

-Reasons to choose from the control options available

-Understand the bits necessary to manage anautomation project

FundamentalsPitfalls


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Automation

automation: A system or method in whichmany or all of the processes of production

movement and inspection of parts and materials are automatically performed or controlled by self-operating machinery,

electronic devices etc.

Websters Dictionary


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Basics

Monitor Evaluate Action

How Do We Control?

Information


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MANUFACTURIN

G

EFFLUENT & ENVIRONMENTMGMT

PRODUCT

WASTE

RAW MATERIA

L

ENERGY

- PROCESSMANAGEMENT.

- QUALITY

- SAFETY

- PRODUCTIVITY / YIELD

- ASSET MANAGEMENT


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Basics

We monitor the temperature.

Is it too cold or too hot?

If so we adjust the tap to correct.

Wait for a bit (system dynamics)

If temperature OK then have shower

Else if temperature not OK adjust again(but with benefit of knowing impact of lastadjustment)

Goto Wait for a bit and repeat.

An Everyday Example


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Measurement

Flow

There are 3 main types of flowmeter types

1. Velocity: measure the velocity flowrate and multiplying by thearea

2. Inferential: determine flow by measuring some other physicalproperty

3. Mass: measure the mass flowrate


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Theory of Electromagnetic Flowmeters

F

Q

-

+U

B

v

F

B

v

= Electric charge

= Magnetic field

= Fluid velocity

= Force

= Voltage

The direction of the inducedvoltage depends on the directionof movement and the magneticfield.

Lorenz Force F L

FL = Q B v

A voltage is induced in an electricconductor moved through amagnetic field.

Q

U


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Measurement

Velocity Flow - Magnetic

Magnetic flowmeters generate a magnetic

field at right angles to the flow stream.Two opposing electrodes them measure the

voltage produced by the fluid movingthrough a conductor.


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Measurement

Velocity Flow Turbine/Paddlewheel

A rotor (like a propeller) is supported by bearings to allow freerotation in the fluid flow.

As the blades spin in the moving flow a pickup device counts thepassing rotor blades and generates a frequency.

As this frequency isproportional to therate of flow and weknow how muchquantity each pulserepresents we cancalculate thevolumetric flow.


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Measurement

Inferential Flow dP Orifice Plate

The orifice plate consists of a flat piece of metalwith a hole bored in it.

When the plate is mounted in

the line a dP (differentialpressure) is created across

the plate.

An instrument that can measure dP

is connected by pipework (calledimpulse lines) to a tapping point oneither side of the plate.

The square root of the dP measured is proportionalto the flow. (This is normally accounted for in the

electronics of the measuring instrument.)


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q ORIFICE METERS

q FLOW IS PROPORTIONAL TO DPq WIDELY USEDq GOOD REPEATABILITY q EASY TROUBLE SHOOTING AND CALIBRATIONq COST EFFECTIVE

q LIMITATIONS

q RANGEABILITY 3:1q INACCURACY INCREASES AT LOWER RANGEq RELATIVE PRESSURE LOSS


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ISO 5167: Orifice plate with corner, flange or D and D/2 pressure tapping

Flow measurement with primary devices

D d

p + p-

p +p -

Pressure tapping via

carrier ring andannular slot

Individualtappings

p = p + - p -

q m(v) = K ( ) 2 p (1)

Diameter ratio of orifice plate:

dD=


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Measurement

Inferential Flow dP Orifice Plate


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Measurement

Inferential Flow dP Various

Venturi Tube

Elbow Taps

Flow Nozzle

Pitot Tube


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Measurement

Mass Flow Coriolis Effect

Tube(s) are forced to oscillate at their natural frequencies perpendicular tothe flow direction.

The resulting Coriolis forces induce atwist movement in the tubes which ismeasured and is related to the massflow.

Two most common types are the

straight tube curved tube


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v =0

v >0

Fc

Fc

m = mass

Fc = Coriolis force

v = Radial velocity

w = Angular velocity

Coriolis Force

F c = -2m v w


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A,B = Sensors

= Phase shift

Fc = Coriolis force

= Angular velocity

y = Amplitude

t = Time

Measurement Signal

~ F c ~

m


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Measurement

Flow Other Methods

Mass: Thermal

Vortex Shedding

Variable Area Flowmeter

Ultrasonic: Transit Time

Ultrasonic: Doppler

Weir & Flume

Target

There are many other methods of measuring flow each with their advantages anddisadvantages


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FLOW MEASUREMENT APPLICATIONS

Qn = A x V VOLUME / TIME

Qm = Qn x d MASS / TIME

DISPLACEMENT

METER : HYDRO CARBON, WATER, VEG OIL

VENTURY TUBES : AIR DUCTS

PITOT TUBES : AIR DUCTS / WATER PIPES > 6

DP Tx : WATER, OIL, STEAM, ACID, CAUSTIC

MAG FLOW METER : WATER, SORBITOL, SOAP SLURRY

MASS FLOW METERS : OIL, PERFUME, CAUSTIC, WATER


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Measurement

Level

Level instruments can be classified into 3 maincategories that measure:

1. The position (height) of the surface

2. The pressure head

3. The weight of the material through load cells.


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Measurement

Level Pressure/Position of Surface

Pressure/Static Head: This type of measurement alsoknown as hydrostatic is based on the height of the liquidhead and the density of the liquid. To calculate the liquidlevel accurately the density must be known and beconstant.

Positon: These instruments detect thesurface of the liquid and include typessuch as

Radar Ultrasonic

FloatDisplacer Nuclear

Capacitance

ConductivityTunin Fork


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Measurement

Level Load Cells

Many forms of load cell exist but mostuse a strain gauge (either foil or

semiconductor) to measure the stresswhich is introduced into a metalelement when it is subjectedto a tensile or compressive force.

A bending beam type designuses strain gauges to monitor thestress in the sensing elementwhen subjected to a bending force .


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Measurement

Temperature

Temperature is probably the most widely used measurement.

Temperature instruments can be classified into 3 main types

1. Thermocouples

2. Resistance (RTDs)

3. Optical


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Measurement

Temperature - Thermocouples

A thermocouple consists of two dissimilar metals, joined together at one end. When the junction of thetwo metals is heated or cooled a voltage is producedthat can be correlated back to the temperature.


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Measurement

Temperature - RTD

RTDs are sensors used to measure temperature by correlatingthe resistance of the RTD element with temperature.

The RTD element is made from a pure material whose resistanceat various temperatures has been documented. The material has apredictable change in resistance as the temperature changes; it isthis predictable change that is used to determine temperature.


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Measurement

Temperature - Optical

The most basic design consists of a lens to focus the infrared (IR) energyon to a detector, which converts the energy to an electrical signal that canbe displayed in units of temperature after being compensated for ambienttemperature variation.

Infrared pyrometers allow users to measure temperature in applicationswhere conventional sensors cannot be employed. Specifically, in casesdealing with moving objects ( i.e., rollers, moving machinery, or aconveyor belt),


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WHAT WILL MAKE A GOOD INSTRUMENT ?

q SENSOR

SMALL IN SIZE / FAST RESPONSE.

RELIABLE, REPEATABLE, STABLE

DURABLE

GOOD DISPLAY CHARACTERISTICS

LOW COST.


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TYPE OF INSTUMENTS AND APPLICATIONS

1 BIMETALLIC LOCAL GAUGES

- PIPES, VESSELS

2 FILLED THERMAL ELEMENTS TEMP SWTCHES

- REMOTE DISPLAY

3 THERMISTORS LOW RANGE

- FAST RESPONSE SWITCHES

4 THERMOCOUPLES REMOTE DISPLAY / CONTROL

- MOST RUGGED

-- WIDE RANGE > 400C

5 RTDs INDUSTRY PREFERRED.FAST, EASY

6 RADIATION PYROMETERS NON CONTACT APPLICATIONS


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Measurement

Pressure

A typical pressure transmitter consists of two parts: the primary elementand the secondary element.

The primary element converts the pressure into an electrical or mechanical or electrical value to be read by the secondary value.

The secondary element is the electronics that output from the primaryelement to a readable signal.


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Measurement

Position

Position and distance sensors detect thepresence or not of items on the move. This canbe used to identify when an item arrives, counthow many items have passed or when an itemhas left.

Position technologies include photoelectric,laser, mechanical switches, proximity switchesand pressure sensors.


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Measurement

Colour

Colour sensors can detect the presence or notof a successful operation. Has the label beenprinted, has the bottle got the right fluid in it, didthe shrink wrap go on successfully


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Measurement

Machine Vision

Machine vision is successfully applied to many industrial inspection problems,leading to faster and more accurate quality control. Machine Vision allows the

manufacturing industry toDetect Defects

Calibrate and control the manufacturing process

Optimise the use of resources


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Measurement

Quality Parameters

pH

Conductivity

Composition

Density

Dust Level

Composition Analysis

Gas Analysers

Brix


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Action

Valves

Output devices allows us to gain control of our system either directly and indirectly.

The small solenoid valve to the right might be usedto switch a pneumatic air supply air to a machineon or off.

The modulating valves to the left canbe used to achieve precise control of a process fluid.

The on/off valve to the right can be used toswitch feeds on and off or, when used inconjunction with other valves, to select routes

through pipework systems.


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Action

Motors

Servo drive motors allow added control

functionality (ramp up, ramp down, torque)and faster positioning.

Stepper motors give precise control of movement.


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Action

Motors

Motors allow us to move things around

whether its a pump moving liquids or aconveyor line moving boxes.


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Action

Equipment

Remote device interfaces allow us tocontrol and talk with an enormous rangeof equipment and devices. This can takethe form of a simple on/off control or a

complex data/control interface.

hi h i k


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Which to Pick

Environment & System

What are the the parameters the device will be exposed to and expectedto perform in during both routine and exceptional circumstances?

What are the performance criteria: speed, size, pass/fail criteria for theline?

With which chemicals and under what conditions will the device beexpected to operate?

What hazards will be present and does this impact on the choice of device?

Whats the commercial impact? Cost v benefit.

Whi h Pi k


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Which to Pick

Accuracy & Repeatability

Poor repeatability gives poor accuracy.

Good repeatability does not always give good accuracy.

Good accuracy means good repeatability.

Which to Pick


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Which to Pick

C l


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Control

Relay (on/off) Control

Relay

C t l


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Control

PLCs Programmable Logic Controllers

As relay logic is on/off control there was an obvious opportunity to imitate withdigital processor systems.

The PLC evolved as an alternative to relay logic with several advantages:

The space required for a large complicated relay logic system could take severalmeters of cabinet space, far more than required by a PLC.

The PLC logic could be modified easily by changing the software program.compared to the problems with re-wiring a relay logic panel.

After the initial development and testing the software logic could be re-used for later similar plants. A repeated relay logic would still have to be wired fromscratch and completely tested to ensure no wiring errors.

C t l


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Control

Loop (analogue) Control

Operator wants 35 degC

Liquid at 30 degC

Open valve a bit more.

Steam supply.

C t l


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Control

DCS Distributed Control System

Replicating the function of loop controllers was a much harder task for the digitalprocessors.

Loop controllers worked in analogue values requiring many on/off bits torepresent one analogue value.

On/Off = 1bit

Analogue = 16 bits 1 0 1 1 1 0 0 1 0 1 1 1 0 1 1 0

1

Process values were changing constantly so the processors had to be ableto read, transfer, process and send out the required output at a much higher frequency.

C t l


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Control

DCS Distributed Control System

As a result of these challenges the processors and equipment required to be thetop end powerful, fast and expensive minicomputer systems.

As the availability and cost of processor systems improved, several systemsuppliers started offering a distributedcontrol solution where severalprocessors were linked together. Eachprocessor had its own geographical or functional area to look after, but was alsoable to communicate with the other processors for coordinated activities

Control


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Control

Modern Control System

The differences between DCSs and PLCs have decreased as the power and availability of computing power has increased dramatically over recentyears: PLCs are arriving with sophisticated control blocks for analoguecontrol requirements and DCSs no longer require large rooms to house theseparate marshalling, conditioning and interface cabinets that used to be thenorm.

DeltaV DCS system Controllogix PLC MOST Hybrid

Putting it all Together


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Putting it all Together

Modern Control System

Documents

Automation Module 01