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PROCESS CONTROLEQUIPMENTS

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SERVOMECHANISMA servomechanism, sometimes shortened to servo, isan automatic deice that uses error!sensin" ne"atie#eed$ac% to correct the &er#ormance o# a mechanismand is de'ned $( its #unction) It usua**( inc*udes a $ui*t!in encoder) A seromechanism is sometimes ca**ed aheterostat since it contro*s a s(stem+s $ehaior $(means o# heterostasis)

USES• Position contro*

• S&eed contro*

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SERVOMOTOR

A rotar( actuator or *inear actuator that a**os #or &recicontro* o# an"u*ar or *inear &osition, e*ocit( and acce*eIt consists o# a suita$*e motor cou&*ed to a sensor #or &o#eed$ac%) It a*so re-uires a re*atie*( so&histicated conto#ten a dedicated modu*e desi"ned s&eci'ca**( #or use

seromotors) Seromotors are not a s&eci'c c*ass o# moa*thou"h the term servomotor  is o#ten used to re#er to asuita$*e #or use in a c*osed!*oo& contro* s(stem)

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 T.PES O/ PER/ORMANCES

• t(&e 0 seros1 under stead(!state conditions the( &roduce a constant

the out&ut ith a constant error si"na*)

• t(&e 2 seros1 under stead(!state conditions the( &roduce a constant

the out&ut ith nu** error si"na*, $ut a constant rate o# chan"e o# the

im&*ies a constant error in trac%in" the re#erence)

• t(&e 3 seros1 under stead(!state conditions the( &roduce a constant

the out&ut ith nu** error si"na*) A constant rate o# chan"e o# the re#e

im&*ies a nu** error in trac%in" the re#erence) A constant rate o# acce*e

the re#erence im&*ies a constant error in trac%in" the re#erence)

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RE4ULATOR

A deice hich has the #unction o# maintainin" a desi"ncharacteristic) It &er#orms the actiit( o# mana"in" ormaintainin" a ran"e o# a*ues in a machine) The measu&ro&ert( o# a deice is mana"ed c*ose*( $( s&eci'ed coor an adance set a*ue5 or it can $e a aria$*e accordin

&redetermined arran"ement scheme) It can $e used "eto connote an( set o# arious contro*s or deices #or re"or contro**in" items or o$6ects)

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 T.PES O/ RE4ULATORS

• Vo*ta"e re"u*ator

• Pressure re"u*ator

• /ue* re"u*ator

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VOLTA4E RE4ULATOR

• Is desi"ned to automatica**( maintain a constant o*ta

*ee*) A o*ta"e re"u*ator ma( $e a sim&*e 7#eed!#ora

desi"n or ma( inc*ude ne"atie #eed$ac% contro* *oo&s

ma( use an e*ectromechanica* mechanism, or e*ectron

com&onents) 8e&endin" on the desi"n, it ma( $e usedre"u*ate one or more AC or 8C o*ta"es)

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PRESSURE RE4ULATOR

• Is a a*e that automatica**( cuts o9 the :o o# a *i-ui

"as at a certain &ressure) Re"u*ators are used to a**o

&ressure :uid su&&*( *ines or tan%s to $e reduced to sa

and;or usa$*e &ressures #or arious a&&*ications)

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/UEL RE4ULATOR