MKS Baratron 221B User manual

|\/|anual
Mr<s
lnstruction
stx SHATTUCK
ROAD,
ANDOVER,
I'/ASSACHUSETTS01810 (538)
975-2350
(800)
227-8766 FAX
(508)
97s-0093
115961-P1
AFt ' A
HF\/ ts 5/qÄ
MKS
Borqfrop@Type221B
Differentiol
PressureGouge

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.lF
Table
of Contents
Table
ofContents
SaferyProceduresandPrecautions.......... "....... I
ChapterOne:
General
Information......... ........3
Introduction......... .................
3
How
This
Manualis
Organized........ .................4
CustomerSupport .......4
Chapter
Two:
Installation.......... .......5
How
To
Unpackthe
Type221Unit ...................5
UnpackingChecklist.......... ..... 5
Setup..... .................6
ChapterThree:Overview .................7
Transducer........... .................7
ExcitationOscillator
......... ...................7
Signal
Amplifiers........... ......7
Demodulator........ ................. 8
Output
DCAmplifier ...........8
InterfaceCables... ........I
I
ChapterFour:
Operation............ ......13
Connector............. ......13
Index ...
15
ill

ListofFigures
List of Tables
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List
ofFigures
Figure
l: Single
andDoubleMetal
Femrle
Compression
Finings......... ...".6
Figure2: Mounting
TheType221Transducer.... ..".......
6
Figure
3: Type 221Block
Diagram ."..............
8
Figure
4: Type221
Schematic
Drawing
C105024 .........9
Figure
5: Type221 OutlineDrawing
Dl10539-A ...".....l0
Figure
6: Cables
forthe200
Series
Transducers....... ....
II
ListofTables
Tablel: Connector
Pinout ..................13
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Safetv
Procedures
and
Precautions
= SafetyProceduresandPrecautions
= DONOTSI'BSTITUTEPARTS ORMODIFT INSTRUMENT
Donotinstall
substitute
parts
or
perform
anyunauthorized
modificationtothe
instrument.
Retumtheinstrument
toanMKSCalibrationandServiceCenterforserviceandrepairto
ensure
= thatallsafetyfeaturesaremaintained.
= sERvrcE By euALrFrED pERsoNNELoNLy
= Operating
personnel
mustnot
removeinstrumentcovers.Component
replacement
and
intemal
adjustmentsmustbemadeby
qualified
service
personnel
only.
DO NOT SERVICE OR ADJUST ALONE
Do notattemptinternalservice
or adjustmentunless
another
person
capableof rendering
firstaid
andresuscitation,ispresent.
USE CAUTION WHEN OPERATING WITH HAZARDOUS MATERTALS
If hazardous
materials
areused,
usersmusttakeresponsibility
to observe
thepropersafety
precautions,
completely
purge
theinstrumentwhen
necessary,
andensure
thatthematerialused
iscompatiblewith sealingmaterials.
PURGE TTTEINSTRUMENT
Afterinstallingthe
unit,
orbefore
its
removalfromasystem, be
suretopurge the
unit
completely
withaclean
drygas
toeliminate
alltraces of the
previously
usedflow material.
USEPROPERPROCEDURES
WHEN
PURCING
= Thisinstrumentmustbe
purged
undera
ventilation
hood,and
gloves
mustbe
wom
to
protect
= Personnel'
= DO
NOTOPERATE
INEXPLOSIVE
ATMOSPHERES
Toavoidexplosion,donotoperatethis
product
inanexplosive
atmosphere
unlessithasbeen
specificallycertified for suchoperation.
=USEPROPER
FITTINGS AND TIGHTENING PROCEDURES
All instrumentfittingsmustbeconsistent
with
instrument
specifications,
andcompatible
with
= theintendeduseoftheinstrument.Assemble
andtightenfittingsaccording
tomanufacturer's
directions.
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Safety
Procedures
andPrecautions
CHECK FOR LEAK-TIGHT FITTTNGS
Before
proceeding
toinstrument
setup,carefullycheck
allplumbing
connectionstothe
instrument
toensureleak-tieht
installation.
OPERATE AT SAFE INLET PRESSURES
Thisunitshould
neverbeoperated
at
pressures
higher
thantherated
maximum
pressure
(refer
to
the
product
specifications
for the maximum
allowable
pressure).
INSTALL A SUITABLE BURSTDISC
Whenoperatingfroma
pressurized
gas
source,asuitable
burst
discshould
be
installed
in the
vacuum
systemtoprevent
systemexplosion
shouldthe
system
pressure
rise.
KEEP THE UNIT FREE OF CONTAMINANTS
Do notallowcontaminantsof anykindto enterthe
unitbeforeorduring use. Contamination
suchasdust,dirt,lint,glass
chips,
andmetalchips
maypermanently
damagethe
unit.
Definitions
of WARNING, CAUTION, andNOTE messages
usedthroughoutthe
manual.
Warning TheWARNING
signdenotes
ahazard.ltcalls
attention
toa
procedure,practice,
condition,
orthelike,which,ifnot
correctly
performed
oradhered
to,could
result
ininjury
to
personnel.
Caution The CAUTION sign denotes
a hazard. It callsattention to an
operatingprocedure,
practice,
or thelike, which, if not correctly
performed or adhered
to,could resultin damage
to or destructionof
all or part of theproduct.
TheNOTE signdenotesimportant
information.It calls
attentionto a
procedure,
practice,
condition,
orthelike,
which
isessentialtohighlight.
II
II
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Chapter
One:
GeneralInformation
TheBaratron@
Type22lB differential
pressure
gauge
consists
of three
elements,
the
indicator,cable
andfansducer.Thesystem isshippedfully interconnected
and
requires
onlytheaddition
of an
external
power
supply
andtheappropriate
readout
device.
The
transducer
consistsofatightly tensioned
diaphragm
onone
side
ofwhich
is
placed
a
dual
electrode;that
is,
asingle-sided system
usablewhenprocess
contamination
is
possible.
Theelectronics
(signal
conditioning
measuring
circuits,andsoforth)iscontained
in aflange-mounted
aluminum
boxon
the
oppositeend
ofthe
transducercable.
An electrical
connector
withamate
is
provided
tomake allinput
power
andoutputsignal
connections.
TheType221
pressure
gauge
has
achieved
CE Mark compliance per
EMC Directive
89t336tEEC.
Note Braided,
shielded
cables
are
requiredtomeet
CEMarkspecifications.
Toorderbraided
shielded
cables,addan S"afterthe
cable
type
designation.
For
example,toorder
an
standard
connection
cableforthe
Type
221transducer,
use
part
number
CB-l 12-14-10; fora braided,
shieldedcable
use
part
number
CB-l
l25-14-10.
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l.
2.
Introduction

Ho*'This
Manual
isOr GeneralInformation
How
This
Manual
isOrganized
This
manual
isdesigned
to
provide
instructions
onhowtoset
up,
install,
and
operate
a
Type221
unit.
Beforeinstalling your Type 22Lunit in a system
and./oroperatingit, carefully readand
familiarize yourself with all precautionarynotesin theSafety
MessagesandProcedures
section
atthefront of this
manual. In addition,observeandobey
all waRxING
and
CAUTION
notes
provided
throughout
the
manual.
Chapter
One,
General
Infurmation,
(this
chapter)introduces
the
product
anddescribes
the
organization
of the
manual.
Chapter
Two,Installatior?,
states
how
tomount
the
instrument
inyour system.
Chapter
Three,Overtiew',
describes
theinstrumentand
itsfunctionality.
ChapterFour,
Operation,
explains
howtouse
the
instrument
and
describes
thefunctions
and
features.
Customer
Support
Standard
maintenance
andrepairservices
areavailableatall of ourregionalMKS Calibration
andService
Centers,
listed
on
the
back
cover.
In addition,MKS accepts theinstruments
of other
manufacturers
for recalibration using
thePrimaryandTransferStandard
calibration
equipment
locatedatallof our
regionalservice
centers.Shouldany
difficulties
ariseinthe use
ofyour
Type221instrument, ortoobtain
information
aboutcompanion
products
MKS offers,contact
anyauthonzedMKS Calibration
andServiceCenter.If it isnecessary
toreturnthe
instrument
to
MKS, please
obtain
an
ERA Number
(Equipment
ReturnAuthorization
Number)
fromthe MKS
Calibrationand
ServiceCenter
beforeshipping.TheERA Numberexpedites
handling
and
ensures
proper
servicing
of yourinstrument.
Pleaserefertotheinsideof the
backcover
of this manualforalist ofMKS Calibration
and
Service
Centers.
Warning Allreturnsto MKSInstruments
mustbe
free
of harmful,
corrosive,
radioactive,or
toxic
materials.
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Chapter
Two:lnstallation
MKS has
carefullypacked theType 221unitsothatit will reach
you in perfect
operatingorder.
Uponreceiving theunit,however,
youshould
check
for defects,cracks,
brokenconnectors,
etc.,
tobe certain
thatdamage
has
notoccurred
during
shipment.
Note Do not discard
anypackingmaterials
until you havecompletedyour
inspectionandare
suretheunit arrivedsafely.
If youfind anydamage,
notify yourcarrier
and
MKS immediately. If it isnecessaryto return the
unittoMKS, obtainan
ERA Number
(Equipment
ReturnAuthorizationNumber)
from the
MKS
ServiceCenterbeforeshipping.Pleaserefer
totheinsideof the
backcoverof thismanual for a
listof MKS Calibrationand
ServiceCenters.
Unpacking
Checklist
Caution Only qualified individuals shouldperform the installation and any
useradjustments. They must comply with all the necessaryESD and
handling precautions
while installing and adjusting theinstrument.
Proper handling is essentialwhenworking with all highly sensitive
precisionelectronicinstruments.
StandardEquipment:
. Type
221
SensorUnit
. Type
221SignalConditioner
Unit
r Type221
InstructionManual
(this
book)
Optional Equipment:
. Electrical
Connector
AccessoriesKit - l2lA-Kl (includes amating
connectorforthe
l4-pin
Ampconnector)
r External
power
supplyandreadout
unit.
r Cablestoconnectthesignalconditioner
toareadout
orcontroller.RefertoInterface
Cables,
page
Il, for information.
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C
e
C
ter
Two: lnstallation c
ar
Lr
t-
Setup
Caution The u'arrantf isvoidif the 221transducer
isinstalled
using
single
or
doublemetalferrule compression
type vacuumfittings (as
shownin).
Thesefittings arecommonly tightened
incorrectly, causing
damageto
thepressure
sensor.
Single
Ferrule Double
Ferrule
Figure
l: Singleand
Double
Metal
Femrle
compression
Fittings
Thetransducer
should
bemounted with the
pressure
portin the
horizontal
position,
as
shownin
Figure
2.
Figure
2: Mountin_e
TheType
221Transducer
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Overview
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Chapter
Three:Overview
Transducer
In the single-sided
sensor,thedual
electrodeisexcited
by secondary
of the transformer
Tl. With
zerodifferentialpressureacrossthediaphragm,
thesignalatthecentertapis atAC ground. As
deflectiontakes
place,thecenter
tap
potential
goes
positive
asthe
capacity
of the
center
electrodeincreasesmorethanthatof the
outside
electrode.
Thisoutput
isamplified
by thesignal
amplifierswhichcorrectfor linearity
and
provide
a zero
adjustment.
Excitation
Oscillator
The l0 kHz oscillatorisof theWeinBridge
type. The
frequencyof operationisdetermined
by
C3,C4 and Rl0, Rl l. TheWeinBridge
isusedas
afeedbackelement
around
amplifierU3 and
produces
the
excitation
whichiscoupled
through
C5and Rl2 todrivethebridge
transformer
and
thedemodulation
input.
Theoscillatorproduces
ahighpuritysinewave
whichisamplitudestabilizedby Q2. ThisFET
amplifiercontrols
the
gain
of theamplifier
U3. Q2 in turniscontrolled by amplifier
Ql which
monitors
the
oscillatoroutputviaapeak
detector.
Theoutput from the
peak
detector
isbalanced
againstatemperature
stabilized
reference
created
by VRI and associatedresistors.
This
combinationproduces
aninput
toQl whichcontrols
theamplitudeby varying the
"resistance"
of
Q2. Adjustment
of theamplifude
over
alimitedrange
is
provided
byR3.
The
first
stage
isapreamplifier
which
provides
ahigh
impedance
input
tothe transduceranda
lowerimpedance
drivingsignaltothe
second
stage
amplifiers
toreduce
the
possibilities
of
unwantedpick-up.The
second
stage
amplifiers
receive
the
signalfromthefirststage.
provide
linearity
adjustment
andzero
control
andthenfeed
the
output
intothe
demodulatortransformer
Tl.
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