AVI AVI-PDU Series User manual

Installationand
OperatingInstructions
SeriesAVI-PDU
RFDRIVENSHIELDLEVELSWITCH

1
GeneralSafetyNotes
1. Forpersonneland equipmentsafety,pleaseusecarewhenliftingand installing
equipment.Totalweightabout5kgorhigherwithcertainlongercableprobesand
over15 kg withflanges.
2. Beawareofthepowerand relay wiringwhendoingcalibrationormaintenance as
highvoltagecanexistontheseconnections.
3. Pay attentionto unsafeconditionswheninstalling theequipmentinthefield.

2
SECTION1INTRODUCTION
1.1SystemDescription
Thisinstruction manualisfortheAVI-PDU Series smart twowireRFadmittance levellimit switch,whichisusedfor
mostlevelmeasurementsandcontrolandissuitableforalmostall industrialorcivilapplicationswheremeasuringlevelof
liquids,powders,slurries andinterface.Theequipmentcanbeeitherinstalledindoororoutdoor,nospecialmounting
requirementsneeded.
Theequipmentisalevelswitchcomprisedofoneelectronicunit,oneconnectingcoaxialcableand onerigidorcable
sensingelement(and alsoit couldbecalledprobe).These componentscanbeconnectedinanintegralconfiguration ora
remoteconfigurationwhichallelectricalcomponentsaremountedawayfromthemeasuringpointandthesensingelement.The
sensingelementcanbemanufacturedofmanydifferentmetalsand insulatorsdependingonthespecificapplication.See figure
1.1as AVI-PDU series integralsystemscheme.
Figure1.1AVI-PDU series RF levelswitch
TheAVI-PDU series RF levelswitchisstrictlyfollowedtheInternational/Chinese standardswhichlistbelow.
1.2OperationPrinciple
RadioFrequencyadmittance leveltechnologyusesabasiccapacitance technology todetectthedifference inmaterials,i.e.
air/powder,air/liquid,oil/water.Butithas advancedfeatures forrejectingcoatings,morereliableand stableoperation,higher
accuracyand remoteelectronics.
RadioFrequencyadmittance technologyemploysacapacitance bridgeand differsfromcapacitance technologyinthe
electronics;cableandsensingelementuses adrivenshieldcircuittostabilize thecoaxialcable.Theelectronicunit smeasuring
(probe)signalisalsopassedthroughaparallelin-phase amplifierinternally.Thisadditionalsignalisconnectedtotheshieldof
thecoaxialcableand thenispassedtothesensingelement sshieldconnection.Thisdrivenshieldamplifierisanin-phase
amplifierwithagainof1.Thesignalon theshieldhas thesamepotential,phase,andfrequencyas themeasuringsignalbutis
electricallyisolatedfromthemeasuringsignalandmeasuringcircuit.Since thecenterwire&shieldwireofthecoaxialcable
havetheaboverelationship,thereisnopotentialdifference betweenthem.Nopotentialdifference meansthatnocurrentflows
betweentheconductors,and no currentflow(leakage)fromthecenterwiretotheshieldmeansthereisno capacitance between
them(capacitance equalzero.)Asaresult,build-up onthesensor,cablelengthandcabletemperaturehaveno affecton the
measurement.Aseparateground wireconnectstheprobegroundtotheelectronicamplifierground.

3
insulating
material
centerrod
inactive shield
Figure 1.2Sensingelementconstruction
TheRFadmittance technologyeliminates theeffectofbuild-uponthesensingelement(usuallycalledcoating),usinga
fivelayercoaxialconfiguration sensingelement(See figure1.2sensingelementinvessel).Themeasuringelementisthecenter
rod,DrivenShieldisthemiddleelement,and theinactive(ground)istheoutsideelement.Eachelementisisolatedfromeach
otherwithanappropriateinsulation material.Asexplainedinthecoaxialcabledescription,thesame signalsareconnectedto
thesensingelement; centerwiretomeasuringelement, shieldtothedrivenshieldelement, and ground toground.
Weputaspecialcircuit tokeepno potentialdifference betweenthemeasuringelement&shieldelement.Whenthereis
somecoatingon theprobe,theimpedance ofthebuild-upislowand measurablecurrentwill notpass fromthemeasuring
elementtotheshieldorground,i.e.UA=UB,IAB=(UA-UB)*YL=0.Theelectronicunitsoonlymeasures thecurrentbetweenthe
sensingelement&probeground(vesselwall).See figure1.3equivalentsketch.Theshieldtoground (vesselwall) potentialis
difference butthiscurrentisnotpart ofthemeasurementcircuit soit does notaffectthemeasurement.Aproprietaryamplifier
circuit keepsthepotentialonthedrivenshieldelementintrinsicallysafeand inbalancewiththemeasuringcircuit.Withthis
techniquethemeasurementcircuit isnotaffectedbybuild-up on thesensingelement. Onlywhenmaterialinthevesselraises up
totouchthecenterrod(measuringsensingelement) couldmakethecurrentflowthrough thematerialfromthecenterrod to
groundtochangethestateofthealarmloop outputcurrent.
ZAC
IAC easured
cerrent
coating
equivalent
circuit
ZAB
ZBC
material B
C
A
notmeasured UA
UB>IAB<0
coating
1.3Equivalentsketch

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SECTION2SPECIFICATION:
2.1Systemspecification:
Measuringcircuit terminals:measurementcategoryII,onlyuse theequipmentformeasurementswithinmeasurementcategory
Iand II, transientovervoltageis2500V.
Output:DPDTreply(doublepoledoublethrow)
ContactRating:250VAC:1Ainductive,3Anon-inductive
Powerrequirement:UniversalPowersupply 30~265VAC, 50/60Hz &21~27VDC
Powerconsumption:2W
Resolution:0.2pForlower
Repeatability:<1mm(conductive)
<20mm(insulating)
Loadresistance:Centerwiretoshield500 , Shieldtoground50
Fail safe:High(HLFS)orlow(LLFS)fieldadjustable
Indicators:Red-levelalarm;Green-systemnormal;Yellow-instrumentfailure
AmbientOperatingTemp.(electronics):-40~+75℃(-40~167℉)
StorageTemp.:-40~+85℃(-40~185℉)
Response time:0.5second
Time delay:2~25seconds(continuouslyadjustable)
Barrier:Built-inlimitingcurrent、three-limitingvoltagebarrier
ESDprotection(forunit): 4KV/8KV
SensingElementIL0.5m(19.7”)standard,0.1m(3.9”)~20m(787.4”)optional
InactiveLength:maxlength50m(164 ft); 50m(1968.5”)~100m(3937”)consult factory
Cablelength:5m(197”)standard,0.1m(3.9”)~50m(1968.5”)optional ＞50m(1968.5”)~100m(3937”)consultfactory
ElectricalConnection:doubleM20×1.5(cablediameterlessthan12mm,0.47”),3/4”NPToptional
Process Connection:Standard:BSPTThread, NPTandFlanges optional
Mounting:vertical, horizontaloranyangle
Ingress Protection:accordwithIP67 requirements
Explosion-proofrating:Exd[ia]iaIICT4
Designedelevation altitude:lowerthan2000m(6562ft)

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SECTION3MODELNUMBER
Probe(sensingelement) specificationsS.E. Mounting
Probes
Numbe
r
IL SHD L/INACTL Wetted
Material
Insula-
tion
Weight
/Anchor
S.E.
Mounting
S.E.Type S.E.Temp.
&Press
Application
18 St.500mm(19.7")
/250mm(9.8")
250mm(9.8")/180mm
(7");80mm(3.1")
/0mm(0")
304SS
(st.)other
optional
PPS NO 3/4"BSPT;
3/4"NPT
optional
OD9mm(0.35")
Threeterminal
rod
100℃/1.0MPa
（212℉/145psi）
25℃/1.6MPa
（77℉/232psi）
Normaltemp.
&pressure
19 St.500mm(19.7")
/250mm(9.8")
250mm(9.8")/180mm
(7");80mm(3.1")
/0mm(0")
316SS PEEK NO 3/4"BSPT;
3/4"NPT
optional
OD9mm(0.35")
Threeterminal
rod
230℃/1.6MPa
（446℉/232psi）
25℃/4MPa
（77℉/580psi）
Mid-
Temperature&
pressure
20 St.500(19.7")
Max2m(78.7")
250mm(9.8")/
180mm(7")
otheroptional
304ss(st.)
other
optional
PTFE NO 2"BSPT;
2"NPT
optional
OD22mm(0.87")
Threeterminal
rod
100℃/1.0MPa
（212℉/145psi）
25℃/1.6MPa
（77℉/232psi）
Heavyduty
anti-agitation
21 04ss(st.)
other
optional
UR NO 170mm*
170mm
(6.7"*6.7")
205mm(8")*
205mm(8")
Threeterminal
flushmounting
82℃/0.2MPa
（180℉/29psi）
25℃/0.5MPa
（77℉/73psi）
Heavyduty
anti-dash
22 St.500mm(19.7")
Max.2m(78.7")
rod;6m(236")cable
250mm(9.8")/180mm
(7")otheroptional
304SS(st)
other
optional
Ceramic
&
copper
NO 11/4"
BSPT;
11/4"NPT
optional
OD9mm(0.35")
Threeterminal
815℃/0.1MPa
（1500℉/15psi）
25℃/2.0MPa
（77℉/290psi）
High
temperature
23 st.2m(787")
Max.8m(315")
cable
250mm(9.8")
/180mm(7")
304SS(st.)
other
optional
PPS Yes 3/4"BSPT;
3/4"NPT
optional
OD9mm(0.35")
Threeterminal
cable
100℃/1.0MPa
（212℉/145psi）
25℃/1.6MPa
（77℉/232psi）
24 Max.3m(118") 304SS(st.)
other
optional
FEP Yes 3/4"BSPT;
3/4"NPT
optional
OD12mm(0.47")
Twoterminal
rod
150℃/2.5MPa
（302℉/363psi）
25℃/4.0MPa
（77℉/580psi）
Smallrange
corrosiveliquid

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SECTION4INSTALLATION
4.1Unpacking
Carefullyremovethecontentsoftheshippingcarton andcheckeachitemsuchas modelnumber,serialnumberof
electronicunit&sensingelement,accessory,instructionmanualetc.Accordingtothepackinglistwithoutdestroyingany
packingmaterials. Ifthereisanyshortageordamage, contact usorlocalagent, packingmaterialneedn trecycle.
4.2Generalrequirements
TheAVI-PDU series levelsystemcanbemountedvertically,horizontallyoratanangle.Becertainthatneitherthe
measuringelementnorthedrivenshieldelementcontactthevesselwall, nozzleoranyobstruction inthevessel.
Thesensingelementshouldbeinstalledusingaproperthreadsealantandtightenedusingthehexwrenchflatson the
inactive(ground)portionoftheprobe. DO NOTtrytotightentheprobebyusingleverageon theprobehousing, Thehousingor
probesealsmaybedamaged.Forlongrigidsensingelementsinagitatedvesselsasupport shouldbeaffixedtotheinactive
section oftheprobetopreventdamage.Longfullyinsulatedsensorsmaybeanchoredinthevessel.Consulteitherthefactory
orlocalrepresentativeforspecificrecommendations.
Electricalconnectionsshouldconformtoplantandnationalstandards.Forhorizontalmounting,instrumentwireentries
shouldbepointeddownwardtothevesselsomoistureisnotcarriedintotheelectricalhousingthroughtheconduit.
Forexplosion-proofinstallationseachwiringentrymusthaveanappropriategas sealdevice.Consult factoryorlocalrep
forsuchfitting.
Instrumentsinstalledoutdoorsinareas oflightningstrikes shouldbeinstalledwithlightningprotection.
24VDC Instrumentpowernoise shouldbelowerthan200mV.
Groundwireshouldbeconnectedtostandardgroundorinstrumentground, mustn tbeconnectedtodynamicground.
Figure4.1AVI-PDU integralsystemmounting
Powerwireshouldbe3terminalarmaturecable,cableO.D.shouldless than12mm,conductormaterialofthecableis
copper,sectionarea shouldbetween0.13 –2.1mm2(AWG14-26),insulatingcapability1500V.Andshouldmeet
IEC60245/60227standardrequirements.AssociatedswitchshouldmeetIEC60947 requirements.
Please considerdoublepowervoltagecapacitance since theinstrumentconsumptionis 2W.
Very Importantinformation forInstallation:ForExplosive proofand safetyreason, the system
housing shouldbe connectto the earthreliably.

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4.3IntegralInstallation
TheAVI-PDU series levelswitchisdesignedandsuitableformostindustrialapplications.Themountinglocationofthe
electronicunitshouldfree ofvibration,corrosiveatmospheres,oranypossibilityofmechanicaldamageformaximumservice
life.Ifthisisnotpossible,consideraremoteelectronicsystem.Mostintegralsystemscanbefieldconvertedtoremote
electronicsystem. Consultyourlocalrepoffactoryforaconversionpartslist.
Forconvenience whenadjustingelectroniccontrols,place theelectronicunitinareasonablyaccessiblelocation.Ambient
temperatureshouldbebetween-40~70oC(-40~158oF ).See figure4.1integralsystemmounting.
4.4RemoteInstallation
Aremotesystemseparates theprobefromtheelectronics withaspecialcoaxialcable(providedbyfactory).Thecablecan
befieldshortenedandre-terminatedas required.DO NOTcoil excess coaxcable.ConnecttheCenterwireofthecabletothe
centerwireterminaloftheunit(CW),connectthecoaxialcableshieldtothedrivenshieldterminal(SHD),andthegroundwire
totheGND terminal.Thegroundwireisusuallyanindependentwirepulledwiththecoaxcable.See figure4.2UFI7P01
Remotemounting.
TheXPhousingofelectronicunitcouldbeinstalledon abracketorwall usingthemountingholes provided. See figure4.3
XPhousinginstallation.
Figure4.2AVI-PDU remotesystemmounting
46(1.8")
52(2")
109.5(4.3")
69.5(2.7")
M6
132(5.2") 33.5(1.3") 57.5(2.63")
102(4")
M6
23.5(0.92")
ElectronicunitProbe
Figure4.3XPhousinginstallation

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4.5SensingElementInstallation
Whenselectinganinstallation point,besurethemeasuring elementwill contact thematerial at thepointthe
alarmshouldbeinitiated.Donotinstalldirectlyunderaflowstreamor feedline.Beawareoftheangle ofrepose
ingranularbinsandsilos,thelevel mustreachtheprobe.Ifasuitable place insidethevessel cannotbefound,
consideranexternal chamberfor liquidmeasurements.Besurethelevel intheexternalbridle tracksthelevel in
thevessel.Payattentiontotheamountofspace abovethevessel,rigidprobesmusthaveadequate head-roomto
install theprobe.
For reliable andtrouble free installationandoperation:
1. Donotdamageor modifytheprobeinsulatorswheninstallingthe instrument/ sensingelement
inthevessel.Besure themeasuring&shieldelementsdo nottouchthenozzleor vesselwall.
2. Donotinstall thesensingelementdirectlyunderaflowstreamor feedline. Ifthisistheonly
positionavailable, use a baffle or shieldabovethe probe tokeepitoutoftheflowstream.
3. Donotopensensingelementor loosensealedgland.
4. Use open-endwrenchonthewrenchflattotightensensingelement. DoNotuse thehousing as
a source ofleverage.
5. Reviewtheinstallationdistancewhenmounting rigidprobe. Keepcableprobeasstraightas
possible toavoidhitting the vesselwall.
6. Longrigidprobesinagitatedvesselsor where excessforce isplacedon theelementshouldbe
supportedusingabracketfromthevesselwall totheinactivesectionoftheprobe. Long
flexible probesshouldbe anchoredusingthefactorysuppliedanchor assembly.
7. Payattentiontomoistureor condensationintheconduit it willcausedamagetoelectronicunit.
8. Connectthe ground of the sensingelementto field equipmentsecurely,less than1ohmresistance.
Consult factoryorrepresentativefornon-metallic vessel groundingrecommendations.
CAUTION: DO NOTUSEADOPTMONO-COMPOSITION ENCAPSULAN
(acetic acidwill decayelectricalcomponent).
USESPECIALDOUBLE-COMPOSITION ENCAPSULAN(non-erosive),
pleaseconsult factoryforthe typeof thismaterial.
4.6Typicalmounting
support
mounting
nozzle
mounting flange
mounting
Nozzle/Flange mounting Insulation Supportmounting

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Anchormounting Bentmounting
Bracketmounting in open vesselExternalside armmounting