field instrumentation.ppt

8/9/2019 Field Instrumentation.ppt

1/85

Topics:-

• Instrument Symbols

• Flow / Pressure measurement

• Control Valve

• Control Valve Accessories

• Temperature measurement

• Level measurement

• Control Loops• Instruments Calibration

• Codes, standards Speci!ication

• Sa!ety Instrumented Systems


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INSTRUMENT SYMBOLS


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INSTRUMENT SYMBOLS


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INSTRUMENT SYMBOLS


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INSTRUMENT SYMBOLS


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INSTRUMENT SYMBOLS


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Flow Rate

Flow rate is an indication of how fast a substance moves through

a conduit from one place to another. Flow rate can also be usedto determine the distance a substance moves over a period of

time. Flow rate is usually expressed as

• Volume flow rate

• Mass flow rate

Volume Flow Rate represents the volume of fluid that passes a

measurement point over a period of time. An example

measurement unit is kg per hour. he volume flow rate can be

calculated if the average flow velocity and inside pipe diameter are

known. he calculation is based on the formula

! " A x v

where

! " volumetric flow rate

A " cross#sectional area of the pipev " average flow velocity $flow rate%

FLOW MEASUREMENT


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Mass Flow Rate represents the amount of mass that passes a

specific point over a period of time.

Mass flow rates are used to measure the weight or mass of

a substance flowing through a process operation. &f the

volumetric flow rate and density are known' the calculation is

based on the formula

( " ! x r

where

( " mass flow rate

! " volumetric flow rate

r " density $r " density )rho* %

FLOW MEASUREMENT


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Laminar Flow: +treamlined flow of a fluid where viscous forces are more significant

than inertial forces' generally below a ,eynolds number of -.

Turbulent Flow: (hen forces due to inertia are more significant than forces due to

viscosity. his typically occurs with a ,eynolds number in excess of /.

Volume Flow Rate: 0alculated using the area of the full closed conduit and the

average fluid velocity in the form' ! " V x A' to arrive at the total volume 1uantity of

flow. ! " volumetric flowrate' V " average fluid velocity' and A " cross sectional areaof the pipe.

i!!erential "ressure: he difference in static pressure between two identical

pressure taps at the same elevation located in two different locations in a primary

device.

Stati# "ressure: Pressure of a fluid whether in motion or at rest. &t can be sensed in

a small hole drilled perpendicular to and flush with the flow boundaries so as not to

disturb the fluid in any way.

FLOW MEASUREMENT


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FLOW MEASUREMENT


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Flow Element2ifferential Pressure

• 3rifice Plate• Pitot

• Venturi

A$%anta&es:

• +imple' no moving parts

isa$%anta&es:

• +usceptible to wear in dirty services except vertically• 3rifice edge sharpness affects accuracy

urbine

,otor

A$%anta&es: Accuracy

isa$%anta&es: Moving parts can wear Vortex

4luff 4ody

A$%anta&es: 5o moving parts

isa$%anta&es: 4luff body can corrode

FLOW MEASUREMENT


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Flow Element Positive 2isplacement $P2%

•3val 6ear • +liding Vane

• 5utating 2isk

isa$%anta&es:

• Many moving parts sub7ect to wear

• Prefilters for dirty service

Mass • 0oriolis • hermal Mass

A$%anta&es:

• Very low maintenance $0oriolis%

• 5o moving parts' corrosive fluid may effect element $hermal

Mass%

Magnetic Field $Magmeter% • A0 Field

• 20 Field

A$%anta&es:

• 8ow maintenance element • Very low maintenance

FLOW MEASUREMENT


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ORIFI'E FLOW MEASUREMENT


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STAM" A'TUAL IA( TO

NEAREST T)OUSANT) IN')

U"STREAM

$ * B O R E

+ ,

#

FE

L

$

-$

t

STAM" MAR. NUMBER

RILL +/01 2

STAM" LINE SI3E AN S')E(

BEFORE BORIN4

SILVER SOLER OR

WEL AN 4RIN FLUS)

+/5 t

ORIFI'E FLOW MEASUREMENT


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ORIFI'E 6 ANNUBAR FLOW ELEMENTS


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MA4NETI' FLOWMETER


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ROTAMETER


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Mass Flowmeter 9 Principles of 3peration

'ur%e$ Tube

Tube Vibration:

Process fluid entering the sensor is split' half passing through each flow tube.2uring operation' a drive coil is energi:ed. he drive coil causes the tubes to

oscillate up and down in opposition to one another .


19/85

Si&nal 4enerationMagnet and coil assemblies' called pick#offs' are mounted on the flow tubes. (ire coils

are mounted on the side legs of one flow tube' and magnets are mounted on the side legs

of the opposing flow tube.

;ach coil moves through the uniform magnetic field of the ad7acent magnet. he voltagegenerated from each pickoff coil creates a sine wave. 4ecause the magnets are mounted

on one tube' and the coils on the opposing tube' the sine waves generated represent the

motion of one tube relative to the other.

N Fl T b M ti


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No Flow * Tube Motionhe flow tubes oscillate while one tube moves

downward' the other tube moves upward and then vice versa.

4oth pickoffs # the one on the inlet side and the one on the outlet side # generate sine wave

current continuously when the tubes are oscillating. (hen there is no flow' the sine wavesare in phase.


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Li7ui$ Flow Measurement• Place taps to the side of the line to prevent sediment deposits on the

ransmitter?s process isolators.

• Mount the transmitter beside or below the taps so gases can vent into the

process line.

• Mount drain@vent valve upward to allow gases to vent.

4as Flow Measurement• Place taps in the top or side of the line.• Mount the transmitter beside or above the taps so li1uid will drain into the

process line.

Steam Flow Measurement• Place taps to the side of the line.

• Mount the transmitter below the taps to ensure that the impulse piping will

stay filled with condensate.

• Fill impulse lines with water to prevent the steam from contacting the

ransmitter directly and to ensure accurate measurement at start#up.

FLOW MEASUREMENT


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FLOW MEASUREMENT


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.ee9 im9ulse 9i9in& as s;ort as 9ossible(

For li7ui$ ser%i#e< slo9e t;e im9ulse 9i9in& at least + in#; 9er !oot

=> #m 9er m? u9war$ !rom t;e transmitter towar$ t;e 9ro#ess#onne#tion(

For &as ser%i#e< slo9e t;e im9ulse 9i9in& at least + in#; 9er !oot

=> #m 9er m? $ownwar$ !rom t;e transmitter towar$ t;e 9ro#ess

#onne#tion(

A%oi$ ;i&; 9oints in li7ui$ lines an$ low 9oints in &as lines(

Ma@e sure bot; im9ulse le&s are t;e same tem9erature(

Use im9ulse 9i9in& lar&e enou&; to a%oi$ !ri#tion e!!e#ts an$

blo#@a&e(

Vent all &as !rom li7ui$ 9i9in& le&s(

INSTRUMENT INSTALLATION*4UIELINES


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W;en measurin& a !lui$< !ill bot; 9i9in& le&s to t;e same le%el(

• W;en 9ur&in&< ma@e t;e 9ur&e #onne#tion #lose to t;e 9ro#ess ta9s

an$

9ur&e t;rou&; e7ual len&t;s o! t;e same sie 9i9e( A%oi$ 9ur&in&

t;rou&; t;e transmitter(

.ee9 #orrosi%e or ;ot =abo%e 52 CF D+5+ C'? 9ro#ess material out o!$ire#t #onta#t wit; t;e sensor mo$ule an$ !lan&es(

"re%ent se$iment $e9osits in t;e im9ulse 9i9in&(

.ee9 t;e li7ui$ ;ea$ balan#e$ on bot; le&s o! t;e im9ulse 9i9in&(

A%oi$ #on$itions t;at mi&;t allow 9ro#ess !lui$ to !reee wit;in t;e

9ro#ess !lan&e(

INSTRUMENT INSTALLATION*4UIELINES

S S


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TRANSMITTER "ARTS

FLOW MEASUREMENT


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Orifice Meters"an#es !or ori!ice meters s$all be selected !rom t$e values s$own below

0 --- 625

0 --- 1250

0 --- 2500

0 --- 5000

0 --- 10000

Rotameters (Variable Area Meters)"an#es !or rotameters s$all be selected !rom t$e values s$own below%

0.1 ---- 1.0 x 10

0.12 ---- 1.2

0.15 ---- 1.5

0.2 ---- 2.00.25 ---- 2.5

0.! ---- !.0

0." ---- ".0

0.5 ----5.0

0.6 ---- 6.0

0.# ---- #.0

FLOW MEASUREMENT


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T$%& O' OTRO* VA*V&+ e9en$s on t;e #onstru#tion o! t;e %al%e t;e %al%es are #lassi!ie$ in

$i!!erent names( Val%es are #lassi!ie$ in to two &eneral t89es base$ on

;ow t;e %al%e #losure member is mo%e$: b8 linear motion or rotar8motion( T;e t89es o! t;e %al%es as !ollows:

• ,lobe ales ,ate ales

• /tterfl ales• /all ales

• Ale ale

• 3iap4ram ales

• 3e-sper-4eater ales

• +lie ales 3ierter ales

Vale Operatio:-1. Air to Ope

2. Air to lose

!. Air fail to *oc i t4e same

positio


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'% is numeri#all8 e7ual to t;e number o! U(S( &allons o! water at

,2CF t;at will !low t;rou&; t;e %al%e in one minute w;en t;e9ressure $i!!erential a#ross t;e %al%e is one 9oun$ 9er s7uare in#;(

'% %aries wit; bot; sie an$ st8le o! %al%e< but 9ro%i$es an in$e !or

#om9arin& li7ui$ #a9a#ities o! $i!!erent %al%es un$er a stan$ar$ set

o! #on$itions(

EFINE 'V OF A 'ONTROL VALVEG


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/tterfl Vale /o Assembl

Flas;in& an$ 'a%itation


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Flas;in& an$ 'a%itation

VALVE "LU4S A''ORIN4 TO


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VALVE "LU4S A''ORIN4 TO

FLOW ')RA'TERISTI'S

For blow $own an$

%ent ser%i#es

For 'om9ressor sur&e

#ontrolsFor !ee$ streams

ser%i#es


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VALVE FLOW ')RA'TERISTI'S


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T;e linear #;ara#teristi# %al%e 9lu& is s;a9e$ so t;at t;e

!low rate is $ire#tl8 9ro9ortional to t;e %al%e li!t =)?< at a

#onstant $i!!erential 9ressure( A linear %al%e a#;ie%est;is b8 ;a%in& a linear relations;i9 between t;e %al%e li!t

an$ t;e ori!i#e 9ass area =see Fi&ure below?(

For eam9le< at 02H %al%e li!t< a 02H ori!i#e sie

allows 02H o! t;e !ull !low to 9ass(

LINEAR ')RA'TERISTI'S


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T;ese %al%es ;a%e a %al%e 9lu& s;a9e$ so t;at ea#; in#rement in %al%e

li!t in#reases t;e !low rate b8 a #ertain 9er#enta&e o! t;e 9re%ious !low(

T;e relations;i9 between %al%e li!t an$ ori!i#e sie =an$ t;ere!ore !low

rate? is not linear but lo&arit;mi#(

Table below s;ows ;ow t;e #;an&e in !low rate alters a#ross t;e ran&e

o! %al%e li!t !or t;e e7ual 9er#enta&e %al%e wit; a ran&eabilit8 o! 2 an$

wit; a #onstant $i!!erential 9ressure(

EUAL H ')RA'TERISTI'S


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EUAL H ')RA'TERISTI'S


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Val%e A##essories

+( I/" Trans$u#er

5( "ositioner J( Volume Booster

0( ui#@ E;aust

( Lo#@u9 Rela8

,( Solenoi$

K( Limit Swit#;

I/" Trans$u#er 9

Trans$u#ers #on%ert a #urrent si&nal

to a 9neumati# si&nal( T;e most

#ommon trans$u#er #on%erts a 0*52

mA ele#tri# si&nal to a J*+ 9si&

9neumati# si&nal(

Volume Booster:

Volume Boosters are use$ on t;rottlin& #ontrol %al%es to

9ro%i$e !ast stro@in& a#tion wit; lar&e in9ut si&nal

#;an&es( At t;e same time< t;e !low boosters allownormal "ositioner air !low =an$ normal a#tuation? wit;

small #;an&es in t;e "ositioner in9ut si&nal( e9en$in&

on a#tuator sie< 9a#@in& set an$ t;e number use$<

boosters #an $e#rease %al%e stro@in& times u9 to 2

9er#ent(

V l A i


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%ositioer:-A ale %ositioer is lie a proportioal cotroller. T4e set poit is t4e cotrol

sial from t4e primar cotroller a t4e cotrolle ariable is t4e ale

positio. T4e %ositioer compesates for istrbaces a oliearities.

T4e se of %ositioer are as follo7s8

• 94e t4e sial pressre is ot eo4 to operate t4e cotrol ale.

• To mae split rae bet7ee t4e ales.

• t ca be se to reerse t4e actio of t4e actator from air to ope to air

to close a ice ersa.

• To miimi;e t4e effect of 4sterisis effect.• To miimi;e t4e respose time for t4e ale.

• f t4e actator is spri less %ositioer 7ill be se.

• f t4e ale 4as 4i4 frictio.

Val%e A##essories

Val%e A##essories


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ui#@ E;aust:• !uick exhaust valves allow the cylinder actuator to 1uickly vent one side

to atmosphere' resulting in an almost immediate full#open or full#closed

position. his sudden movement generally limits 1uick exhaustapplications to on@off services where positioners are not used.

Lo#@u9 Rela8:• &t is designed to hold the actuator in the last operating position upon air

failure.

Solenoi$:• Dsed o 3pen he Valve 3r 0lose it

Limit swit#;:• 8imit switches are available to indicate a valve open or closed position.

Swit#;in& Val%e:• &t is used in fail lock up system for to set the air pressure in the re1uired

level for lock the valve.

Val%e A##essories


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Tem9erature Measurement


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Resistan#e bulbs shall be selected in accordance with the following9

,esistance bulbs should be used when the working temperature is between#-o0 and /o0' and precise measurement is re1uired.

4ulbs shall be fitted with platinum resistance elements. And normally

," the resistance drops nonlinearly with temperature rise.

Strain 4a&e: A measuring element for converting force' pressure' tension'

etc.' into an electrical signal.

W;eatstone Bri$&e: A network of four resistances' an emf source' and agalvanometer connected such that when the four resistances are matched'

the galvanometer will show a :ero deflection or EnullE reading.




43/85

Flui$*e9ansion $e%i#es:

ypically like household thermometer' generally come in two main classifications9# mercury type

# organic#li1uid type

Versions employing gas instead of li1uid are also available.

Mercury is considered an environmental ha:ard' so there are regulations governingthe shipment of devices that contain it.

Fluid#expansion sensors do not re1uire electric power' do not pose explosion

ha:ards' and are stable even after repeated cycling.

3n the other hand' they do not generate data that are easily recorded or

transmitted' and they cannot make spot or point measurements




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Seebe#@ E!!e#t: (hen a circuit is formed by a 7unction of two dissimilar

metals and the 7unctions are held at different temperatures' a current will flow

in the circuit caused by the difference in temperature between the two 7unctions.

T;ermo#ou9le: he 7unction of two dissimilar metals which has a voltage

output proportional to the difference in temperature between the hot 7unction

and the lead wires $cold 7unction%.

'om9ensatin& Lea$ Wires an$ Etension Wires

he compensating lead wires and extension wires shall conform to A5+&

M0C.


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TT&+O 9R&

MAT&RA* +A MAT&RA* O*OR O' +=*ATO

?V& -V& +$M ?V& -V& ?V& -V& OV&RA**

opper ostata T opper ostata /le Re /le

ro ostata @ ro ostata 94ite Re /lac

4romel Almel 4romel Almel $ello7 Re $ello7

4romel ostata & 4romel ostata %rple Re %rple

T


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In!rare$ sensors


47/85

E 5

E

0352D& 0355.

EAE




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49/85

@= H


50/85

'iel-Mote T4ermometers"an#es !or !ield&mounted t$ermometers s$all be selected suc$ t$at normal operatin#

temperature is around '() o! t$e !ull scale%

*+nit -e#% C%.

-50 --- 50

-!0 --- 50

0 --- 50

0 ---100

0 --- 120

0 --- 150

0 --- 200

0 --- 250 0 --- !00

0 --- "00

0 --- 500

100---500


Le%el Measurement


51/85

ype of level Measurements9

• ,eflex Flat 6auge 6lass• ransparent Flat 6auge 6lass• Magnetic Float• Float +witch

• or1ue ube 2isplacer • 2isplacer +witch• 4ubbler ube• Iydrostatic Iead ;xample @ 2ifferential Pressure

• Dltrasonic• 5uclear

Le%el Measurement

Le%el Measurement


52/85

+tand pipe

A large pipe' usually / inches in diameter' mounted on the side of vessel.8evel measurement devices' such as sight gauges and pressure

transmitters' are attached to the pipe. he standpipe serves to transmit level

to more than one device. Also referred to as bridle or stilling well.

appings

0onnections to a vessel to which a measurement device?s

no::le@flange is attached.

&nterface

he point or location where two phases meet. &n a li1uid level measurement'

two non#mixing li1uids of different specific gravities and color establish a

boundary that can be viewed as a distinct line.

Le%el Measurement

Le%el Measurement


53/85

W;en t;e LEVEL in %essel is at or below t;e bottom #onne#tion t;e !or#e on t;e ;i&; 9ressure le& =t;e

lower %essel nole? will see +51 +(2 +51 W'(

T;e low 9ressure le& =t;e ;i&;er %essel nole? will

see ++51 +(2 ++51 W'(

T;e $i!!erential is +51 W' * ++51 W' *+221 W'(

W;en t;e %essel is !ull< t;e !or#e on t;e ;i&; 9ressure

le& will be +51 +(2 +221 2(> +5 > ++21 W'(

T;e low 9ressure si$e will see ++51 +(2 ++51 W'(

T;e $i!!erential is ++21 W' * ++51 W' *51 W'(

T;e transmitter s;oul$ be #alibrate$ !or

*+22 to *51 W'(

Le%el Measurement

i!! "ressure T89e

Le%el Measurement


54/85

he force of the li1uid head is linear with mass if the vessel is vertical withstraight sides.

&f the readout is calibrated in mass of material $instead of volume of

material%' the reading will be correct for any specific gravity as long as it is

within the live area of calibration and ignoring the small error from the heelof the vessel.

he vessel may not be full at


55/85

Le%el Measurement

is9la#er T89e

3isplacer imesio 0 ---!56 0 ---#1! 0 ---121E 0 ---152" 0 ---1#2E

Le%el Measurement


56/85

Le%el Measurement

Ser%o 4au&e T89e Bubbler T89e

Le%el Measurement


57/85

Le%el Measurement

Ultrasoni# T89e

Use o! non*#onta#t

instruments s;oul$

be #onsi$ere$ !or

a99li#ations in

#orrosi%e

toi# ;i&;l8 %is#ous

slurries 6 ;ea%8

or irre&ularl8

s;a9e$ bul@

materials orw;ere 9robes #an

be $ama&e$ b8 t;e

9ro#ess(

Le%el Measurement


58/85

++KKJ MM

LI22JA

LI2JB

J>J MM

>, MM

J20> MM

Le%el Measurement

Nu#lear T89e Nu#lear instruments ;a%e a ra$iationsour#e an$ $ete#tor( T;e sour#e

ra$iates t;e si&nal t;rou&; t;e %essel tot;e $ete#tor( T;e mass in t;e %essel

absorbs t;e ra$iation an$ blo#@s a

9er#enta&e o! it !rom rea#;in& t;e

$ete#tor(

A $esi&n in%ol%in&

nu#lear instruments

nee$s to 9ro%i$e a wa8to s;iel$ t;e sour#e< t;e

abilit8 to lo#@ out t;e

sour#e< an$ t;e 9ostin&

o! warnin& si&ns(

Steam rum : Le%el 'ontrol


59/85

Steam rum : Le%el 'ontrol

Le%el Measurement


60/85

Le%el Measurement

Le%el Measurement


61/85

Ma&neti# 4au&es

A ma&neti# &au&e is a metal tube wit; an internal !loat ma&neti#all8 #ou9le$

to an in$i#ator on a s#ale on t;e outsi$e o! t;e tube(

Ma&neti# &au&es s;oul$ be #onsi$ere$ as an alternati%e to &lass !or

!lammable< #orrosi%e< toi#< ;i&; 9ressure< ;i&; tem9erature< or lon& %isible

len&t; ser%i#e(

T;e installation o! t;e ma&neti# le%el &au&e s;oul$ be t;e same as !or &lass

le%el &au&es( T;e e#e9tion is t;at t;e en$ #onne#tion s;oul$ be !lan&e$ an$

e#ess !low ball #;e#@ %al%es are not re7uire$(

T;e !loats in ma&neti# le%el &au&es are t;in*walle$ an$ ma8 #olla9se !rom

e#essi%e 9ressure =e(&(< ;8$ro testin&?(

Ma&neti# &au&es s;oul$ not be use$ !or li7ui$s #ontainin& $irt or sus9en$e$

soli$s(

irt #an #ause t;e !loat to sti#@ resultin& in !alse in$i#ations( T;e !loat in a

ma&neti# &au&e is en&ineere$ !or a #ertain ran&e o! li7ui$

$ensities(

Le%el Measurement

'ONTROL LOO"


62/85

• "rimar8 Element: T;e measurin& element t;at 7uantitati%el8 #on%erts t;emeasure$ %ariable ener&8 into a !orm suitable !or measurement(

Note: T;e sensin& 9ortion is t;e 9rimar8 element !or transmitters t;at $o not;a%e eternal 9rimar8 elements(

• Transmitter: A trans$u#er w;i#; res9on$s to a measure$ %ariable b8 meanso! a sensin& element< an$ #on%erts it to a stan$ar$ie$ transmission si&nalw;i#; is a !un#tion onl8 o! t;e measure$ %ariable(

• 'ontrolle$ Variable: A %ariable t;e %alue o! w;i#; is sense$ to ori&inate a!ee$ba#@ si&nal( =Also @nown as t;e 9ro#ess %ariable(?

• 'ontroller: A $e%i#e w;i#; o9erates automati#all8 to re&ulate a #ontrolle$%ariable(

• 'ontroller Al&orit;m ="I?: A mat;emati#al re9resentation o! t;e #ontrola#tion to be 9er!orme$(

• Set "oint: An in9ut %ariable w;i#; sets t;e $esire$ %alue o! t;e #ontrolle$%ariable(

'ONTROL LOO"

'ONTROL LOO"


63/85

'ONTROL LOO"

'ONTROL LOO"


64/85

Error

In 9ro#ess instrumentation< t;e al&ebrai# $i!!eren#e between t;e real %alue

an$ i$eal %alue o! t;e measure$ si&nal( It is t;e 7uantit8 w;i#; w;enal&ebrai#all8 subtra#te$ !rom t;e in$i#ate$ si&nal &i%es t;e i$eal %alue(

Mani9ulate$ Variable

A 7uantit8 or #on$ition w;i#; is %arie$ as a !un#tion o! t;e al&ebrai# error

si&nal so as to #ause a #;an&e to t;e %alue o! t;e $ire#tl8 #ontrolle$ %ariable(

Fee$ba#@ 'ontrol

'ontrol a#tion in w;i#; a measure$ %ariable is #om9are$ to its $esire$ %alueto 9ro$u#e an a#tuatin& error si&nal w;i#; is a#te$ u9on in su#; a wa8 as tore$u#e t;e ma&nitu$e o! t;e error(

'as#a$e 'ontrol

'ontrol in w;i#; t;e out9ut o! one #ontroller is intro$u#e$ as t;e set 9oint !oranot;er #ontroller(

'ONTROL LOO"


65/85

"ro9ortionin& Ban$: A temperature band expressed in degrees within which a

temperature controllerKs time proportioning function is active.

"ro9ortionin& 'ontrol 9lus eri%ati%e Fun#tion: A time proportioning controller

with derivative function. he derivative function senses the rate at which a systemKs

temperature is either increasing or decreasing and ad7usts the cycle time of the

controller to minimi:e overshoot or undershoot.

"ro9ortionin& 'ontrol 9lus Inte&ral: A two#mode controller with time

proportioning and integral $auto reset% action. he integral function automatically

ad7usts the temperature at which a system has stabili:ed back to the set point

temperature' thereby eliminating droop in the system.

"ro9ortionin& 'ontrol wit; Inte&ral an$ eri%ati%e Fun#tions: hree mode

P&2 controller. A time proportioning controller with integral and derivative functions.he integral function automatically ad7usts the system temperature to the set point

temperature to eliminate droop due to the time proportioning function. he

derivative function senses the rate of rise or fall of the system temperature and

automatically ad7usts the cycle time of the controller to minimi:e overshoot or

undershoot.

FEEBA'. 'ONTROL LOO"S


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FEEBA'. 'ONTROL LOO"S


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TRANSMITTERS * 'ONTROL LOO"S


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W;at is )ARTG

IA, $EIighway Addressable ,emote ransducerE% is a communication

protocol designed for industrial process measurement and control

applications.

&tKs called a ;8bri$ protocol because it combines analog and digital

communication.

&t can communicate a single variable using a /#- ma analog signal' while

also communicating added information on a digital signal. he digital

information is carried by a low#level modulation superimposed on the

standard /#to#- mA current loop.

he digital signal does not affect the analog reading because itKs removed

from the analog signal by standard filtering techni1ues.

he ability to carry this added digital information is the basis for IA,Ks

key benefits

Transmitters * 'alibration


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)ow to use )ARTG

INSTRUMENT 'ALIBRATION


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'alibration: he process of ad7usting an instrument or compiling a deviation chart so

that its reading can be correlated to the actual value being measured.

A##ura#8: he closeness of an indication or reading of a measurement device to the

actual value of the 1uantity being measured. Dsually expressed as H percent of full

scale.

Error: he difference between the value indicated by the transducer and the true

value of the measurand being sensed. Dsually expressed in percent of full scaleoutput.

Re9eatabilit8: he ability of a transducer to reproduce output readings when the

same measurand value is applied to it consecutively' under the same conditions' and

in the same direction. ,epeatability is expressed as the maximum difference

between output readings.

Ran&e: hose values over which a transducer is intended to measure' specified by

its upper and lower limits.


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Field Instrument utput Si#nal#enerated by

C$ec0 Points "emar0s

Pressure 6au#e, -ra!t

6au#e

&&&&& Atm% Pressure &&&&&

Field TemperatureTransmitter *mV/7, "/7 etc%.

mV source, resistancesource and precisiontype test indicator

(, 2(, 3(() o! span bot$ increasin# anddecreasin#

C$ec0 output si#nala#ainst receiverinstrument indication

T$ermometer Temperature bat$ Amb% Temperature

T$ermometer s$all bec$ec0ed wit$ a temp% bat$ and a standardt$ermometer%

&&&&&&

-isplacer Type Level

Instrument

Immersin# t$e

displacer in water

(,2(, 3(() o! span

bot$ increasin# anddecreasin#

C$ec0 output si#nal

a#ainst receiverinstrument indication

8all Float Type Level Actuatin# t$e switc$mec$anically

&&&&& C$ec0 alarm li#$t,solenoid valve,se5uence andinterloc0, etc%



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Field Instrument utput Si#nal#enerated by

C$ec0 Points "emar0s

Tan0 6au#e "aisin# t$e !loatmec$anically orelectrically

*3. 9ero point*:. Smoot$ !latmovement

*3. C$ec0 receiverinstrument indication*:. Prior to c$ec0in#, t$etan0 level must becon!irmed as ;ero

Control Valve

*Controller utput.

Controller manual

output

(, 2(, 3(() o!

t$e valve stro0e, bot$ increasin#and decreasin#

*3. C$ec0 t$e valve stro0e

a#ainst t$e travel indicator *:. C$ec0 t$e valve actionat air !ailure*


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TY"E "RO'ESS 'ONNE'TIONS / SI3E

Pneumatic Si#nals >PT 3/= in !emale / 'mm / ? mm

7lectronic Si#nals

*@eat$erproo! or 7plosion proo!

>PT 3/: in !emale

-i!!erential Pressure Instruments*Pressure Connection.

>PT B in !emale-iap$ra#m : or < in Flan#ed

T$ermowell Flan#ed 6eneral Service 3 in

1i#$ Velocity Service 3 3/: in

@elded 6eneral Service 3 in

1i#$ Velocity Service 3 3/: in

Screwed PT 3/: in !emale

-iap$ra#m :D Flan#ed

Pressure #au#es *8ourdon. &&& >PT 3/: in !emale


-ra!t 6au#es >PT 3/= in !emale

INSTRUMENT "RO'ESS 'ONNE'TIONS


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TY"E "RO'ESS 'ONNE'TIONS / SI3E

Level Instruments Flan#e Type-i!!erential

PressureInstrument


-P Transmitters >PT 3/: in !emale

-isplacer 7ternalInternal

:D Flan#e=D Flan#e

6au#e 6lass


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+tep


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T;e !ollowin& #o$es an$ stan$ar$s< to t;e etent s9e#i!ie$ ;erein< !orm a

9art o! t;is esi&n 'riteria( W;en an e$ition $ate is not in$i#ate$ !or a #o$e

or stan$ar$< t;e latest e$ition in !or#e at t;e time s;all a99l8(

+( International Ele#tri#al 'ommission =IE'?

5( National Ele#tri#al 'o$e =NE'?

J( National Ele#tri#al Manu!a#turers Asso#iation =NEMA?

0( Ameri#an National Stan$ar$ Institute< In#( =ANSI?

( Instrument So#iet8 o! Ameri#a =ISA?

,( Institute o! Ele#tri#al an$ Ele#troni# En&ineers =IEEE?

K( International Stan$ar$s Or&aniation =ISO?

>( Ameri#an "etroleum Institute =A"I?

( A"I R"2: Installation o! Re!iner8 Instruments An$ 'ontrols S8stems

+2( A"I Stan$ar$ ,K2:Vibration< Aial*"osition an$ Bearin& Tem9erature

Monitorin& s8stems


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FAILURE ISTRIBUTION OVER T)E SIS 'OM"ONENTS


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FAILURE ISTRIBUTION OVER T)E SIS 'OM"ONENTS

• SENSORS 05H

• LO4I' SOLVER >H

• FINAL ELEMENTS 2H

• USUALLY T)E LO4I' SOLVERS ="L's? RE'EIVE 4REATERATTENTION< W)EREAS T)E FIEL EVI'ES ARE RES"ONSIBLE FOROVER 2H OF T)E FAILURES

SE"ARATION OF SIS AN B"'S


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• )5ormally' the logic solver$s% are separated from

similar components in the 4P0+.Furthermore' +&+ input sensors and final control

elements are generally separate from similar

components in the 4P0+.*

)Provide physical and functional separation and

identification among the 4P0+ and +&+ sensors'

actuators' logic solvers' &@3 modules' and chassis.*


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A"I

• )he safety system should provide two levelsof protection.. he two levels of protectionshould be independent of and in addition tothe control devices used in normal operation.*

NF"A

• ),e1uirement for &ndependence9 he logic

system performing the safety functions forburner management shall not be combinedwith any other logic system*.



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&;;;

• )he safety system design shall be such that

credible failures in and conse1uential actions

by other systems shall not prevent the safety

system from meeting the re1uirements*.

DN Iealth and +afety ;xecutive

• )&t is strongly recommended that separate

control and protection systems are provided.*

field instrumentation.ppt

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