Metal Samples CORR Velox MS2800E User manual

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Ultra Resolution ER RS-485 Transmitter
(Model MS2800E)
Operator’s Manual
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Metal Samples Company
ADivision of Alabama Specialty Products, Inc.
152 Metal Samples Rd., Munford, AL 36268 Phone: [phone] Fax: [phone]
E-mail:[email protected] Internet: www.metalsamples.com

Table of Contents
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I.Introduction..............................................................................................................................................1
A.GeneralDescription...................................................................................................................1
B.PrinciplesofOperation..............................................................................................................1
C.TechnicalSpecifications.............................................................................................................3
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II.InstallationandOperation.......................................................................................................................4
A.ReceivingtheCorrVeloxtransmitter.....................................................................................4
B.Installation.................................................................................................................................4
1.PhysicalMountingandProbeConnection...................................................................4
a.Direct‐ProbeMounting......................................................................................4
b.RemoteMounting..............................................................................................5
2.PowerandDataConnections.......................................................................................5
a.MakingConnections.........................................................................................5
b.Grounding.........................................................................................................6
c.SafeAreaInstallation........................................................................................7
d.HazardousAreaInstallation...............................................................................7
3.SetupandOperation.......................................................................................................9
a.ProbeSettings.................................................................................................9
b.RS‐485CommunicationSettings...................................................................10
i.BaudRateandDefaultCommunicationParameters.............................11
ii.DeviceAddress......................................................................................11
iii.CommunicationProtocols......................................................................11
iv.TerminationResistor.............................................................................11
v.DataRegisters.......................................................................................12
c.CalibrationandTesting.................................................................................12
i.Calibration...............................................................................................12
ii.Testingoutputzeroandspan.................................................................12
iii.TestingtheCorrVeloxtransmitterwiththeMeterProver.................13
d.InterpretingData...........................................................................................13
i.MetalLoss................................................................................................13
ii.CalculatingCorrosionRate.......................................................................14
e.Commissioning..............................................................................................16
C.Maintenance............................................................................................................................16
D.Troubleshooting........................................................................................................................17
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III.ServiceandWarrantyInformation.......................................................................................................18
A.Warranty...................................................................................................................................18
B.ObtainingServiceandReturningtheInstrumentforRepair....................................................18
C.InstrumentRepairForm............................................................................................................19
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AppendixA‐Drawings...............................................................................................................................20
ControlDrawing(HazardousAreaWiringDiagram).....................................................................21
SafeAreaWiringDiagram.............................................................................................................22
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AppendixB–RevisionHistory...................................................................................................................24

1
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I.Introduction
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A.GeneralDescription
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ThemodelMS2800ECorrVelox transmitterisanultra‐highresolutioninstrumentdesignedto
measureandtransmitcorrosion(metalloss)datafromanElectricalResistance(ER)probetoaplant
controlsystemorotherrecordingdevice.TheCorrVelox transmitterutilizesRS‐485
communicationwhichallowsmultipleunitstobedaisy‐chained,simplifyinginstallationandreducing
associatedcosts.TheuseoftheRS‐485protocolalsoallowsthetransmittertobeplacedgreat
distancesfromthecontrolsystemorrecorderwhilemaintaininggoodnoiserejection.Practical
distancescanbeupto4000feet.Additionally,theCorrVelox transmitteroffersuser‐selectable
RTUorASCIIcommunicationprotocolsmakingithighlyversatile.
TheCorrVelox transmitteriscompatiblewithalltypesofMetalSamplesERprobes,aswellasany
standardERprobefromothermanufacturers.Unlikecompetitors’products,theCorrVelox
transmitterdoesnotrequirefactorymodificationtoaccommodatedifferentprobetypes.Theprobe
typecanbeeasilychangedatanytimeusingtheon‐boardprobeselectionswitches(seepage9.)
TheCorrVelox transmitterisavailableasdirect‐mount(standard)orremote‐mount.Thedirect‐
mountversionismounteddirectlytotheERprobe.Thisoptionoffersthesimplestinstallationand
minimizesnoiseproblems.Theremote‐mountoptionallowstheCorrVelox transmittertobe
mountedindependentlyfrom(butincloseproximityto)theERprobe.Itisthenconnectedtothe
probeviaashortprobecable.(Seepages5and6formountingdiagramsandspecifications.)
B.PrinciplesofOperation
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TheCorrVelox transmitteroperatesontheElectricalResistance(ER)techniqueandisusedin
conjunctionwithanERprobe.TheERprobeutilizesaresistivesensingelementmanufacturedfrom
thematerialofinterest(oracloseapproximation)whichisexposedtoacorrodingenvironment.This
iscalledtheExposedorCorrodingElement.TheresistanceoftheExposedElementisdirectlyrelated
toitsthickness,soastheelementcorrodestheresultinglossofmetalcausesaproportionalincrease
intheelement’sresistance.TheprobealsocontainsaninternalReferenceElementwhichisusedto
compensatefortheinfluencesoftemperatureontheExposedElement.
TheCorrVelox transmitterisdesignedtoworkwithanystandardERprobe,butitisrecommended
thatCylindricalandLargeFlushtypeprobesbeusedtoensureoptimumperformance.Theirphysical
designplacestheReferenceElementincloserproximitytotheExposedElementcomparedtoother
probetypes,providingmoreeffectivetemperaturecompensationandthusreducingtheeffectsof
thermalnoise.
Becausetheyaredesignedtocorrode,ERprobesaresacrificialinnature.EachERprobewillhavea
finitelifethatisbasedontheelementthickness.ERprobesareavailableinanumberofgeometries
andthicknessesdesignedtosuitawidevarietyofapplications.Table1liststhecommonERelement
optionsavailablefromMetalSamplesandtheeffectivelifeofeach.

2
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ElementTypeCompatibilityThicknessProbeLife
(Span)
TubularLoopCompatible
42
84
WireLoopCompatible
4010
8020
Flush(Small)Compatible
4 2
8 4
20 10
CylindricalPreferred
10 5
20 10
50 25
Flush(Large)Preferred
52.5
10 5
20 10
40 20
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Table1.StandardERProbeElements
TheCorrVelox transmittermeasuresanERprobeutilizingahigh‐resolution,20‐bitmeasurement.
Thisallowstheunittodetectmuchsmalleramountsofmetalloss,thusrespondingfasterto
corrosioneventsandupsets.At20‐bitresolutiontheCorrVelox transmittercanmeasuremetal
lossamountsassmallas0.0001%oftheprobelife.Forhighlysensitiveprobessuchasthe5‐mil
largeflushshownabove,thatresultsinadetectionlimitoflessthanoneangstrom.
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MetallossreadingstakenbytheCorrVelox transmitterareoutputasadigitalRS‐485signalwhich
canbefedintoaplantcontrolsystemorotherrecordingdevices.TheMetalLossisrepresentedby
a20‐bitdigitalvaluebetween0and1,048,575,where:
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0=0mils(0%MetalLoss)
1,048,575=ProbeLife*inmils(or100%MetalLoss)
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*TheProbeLife(orSpan)oftheprobebeingused(seetable1above.)
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TheMetalLossdatacanbeusedtocalculatethecorrosionratebetweenanyperiodsofinterest.
Thisiscoveredinmoredetailonpages13and14.MoreinformationonERprobes,theirtheory,
selection,andusecanbefoundonourwebsiteat http://www.alspi.com/erintro.htm.
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3
C.TechnicalSpecifications
ModelMS2800ECorrVeloxUltra‐HighResolutionERRS‐485ModbusTransmitter
PhysicalData
InstrumentWeight: 3.70lb.(1.68Kg)
TotalWeightw/Accessories:5.76lb.(2.61Kg)
InstrumentDimensions:6.0"Hx4.0"Dia
(15.25cmHx10.16cmDia)
OperatingTemperature: ‐4°to158°F(‐20°to70°C)
StorageTemperature: ‐40°to176°F(‐40°to80°C)
EnvironmentalRating: IP66
EnclosureMaterial:316StainlessSteel
MountingSpecifications:Directprobemount(standard)
Maybepolemountedusingoptionalhardware
(Uptoa2.5”(6.35cm)Dia.pole)
PerformanceData
MeasurementType:ERmeasurementusinganystandardERprobetype
(WireLoop,TubeLoop,Cylindrical,Flush,Strip,etc.)
Range:0‐100%ofprobelife
Resolution:0.0001%ofProbeLife(20‐bit)
CycleTime:75Seconds
ElectricalData
PowerRequirements:10to28VDC
MaximumProbeCableDistance:30ft(9.1m)
OutputSpecifications:RS‐485Modbus,RTUorASCIIProtocol(SwitchSelectable)
2400/4800/9600/19.2KSelectableBaud
32MaximumUnits(Addresses1to32)
HazardousLocationCertifications–IntrinsicSafety
USA/CanadaConformstoANSI/ULStd.60079‐0,60079‐11,61010‐1
CAN/CSAStd.E66079‐0,E60079‐11&CAN/CSAC22.2No.61010‐1
ForStand‐AloneUseForMulti‐DropUse
ClassI,Zone0,AExiaIICT4GaClassI,Zone0,AExiaIIBT4Ga
Zone20,AExiaIIICT130°CDaZone20,AExiaIIIBT130°CDa
‐20°C≤Ta≤+70°C‐20°C≤Ta≤+70°C
EuropeandWorldwideForStand‐AloneUseForMulti‐DropUse
(ATEXandIECEx)II1GExiaIICT4GaII1GExiaIIBT4Ga
II1DExiaIIICT130°CDaII1DExiaIIIBT130°CDa
‐20°C≤Ta≤+70°C ‐20°C≤Ta≤+70°C
ATEXCertificateNo:ITS14ATEX28092X
IECExCertificateNo:IECExITS14.0052X
X–seeSpecialConditions(page7)
IncludedAccessories
33’(10M)WiringHarness,MeterProver,OperationsManual
OptionalAccessories
ProbeExtensionCable,RemoteMountingHardware
4.0”Dia
(10.16cm)
6.0”H
(15.25cm)
Figure1.OverallDimensions

4
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II.InstallationandOperation

A.ReceivingtheMS2800ECorrVelox Transmitter

ChecktheCorrVelox Transmitterforanyshippingdamagewhenitisfirstreceived.Whentheunitis
unpacked,verifythatthefollowingitemsareincluded:

Transmitter
WiringHarness
MeterProver
User’sManual
ProbeCable(optional,forremote‐mountonly)
MountingHardware(optional,forremote‐mountonly)

Intheeventofshippingdamage,quantityshortage,ormissingitems,itisrecommendedthatthe
eventisdocumentedimmediatelyandthatdigitalphotographsaretaken.Anyshortagesormissing
itemsshouldbereportedtoMetalSamplesimmediately.Intheeventofshippingdamage,aclaim
shouldbeopenedwiththeresponsiblecarrier.
B.Installation

CAUTION:Usingthisproductinanywayotherthanthatspecifiedwithinthismanualmayimpairthe
intrinsicsafetyprotection.


InstallationoftheCorrVelox transmitterinvolvesthefollowingsteps:

1. PhysicalMounting
2. ElectricalConnection
3. SetupandProgramming

1.PhysicalMountingandProbeConnection

WhenselectingalocationtomounttheCorrVelox transmitteritisimportanttoconsiderthe
surroundingenvironment.Toensureproperoperation:

Donotmountthetransmitterinalocationthatexceedsitsoperatingtemperature.
Avoidmountingthetransmitternearsourcesofstrongelectricalnoise.
Ensurethatthereissufficientclearanceforinstallationandtoopenthetransmittercover
afterwards.

a.Direct‐ProbeMounting
TheCorrVelox transmitterisdesignedfordirect‐probemountingwhicheliminatestheneedfor
additionalhardwareandtransmitter‐to‐probecabling.Thisgreatlysimplifiesinstallation,reduces
costs,andminimizeselectricalnoisethatcanbecoupledontoprobecablingfromnearbyelectrical
equipment.

BeforemountingtheCorrVelox transmitter,firstensurethattheprobeisinstalledproperlyand
securely.Duringinstallationitisimportantthatyoudonotapplyexcessiveforceontheprobeor
seals,asdoingsocouldbreakthesealandresultinsystemleakage.

5

TomounttheCorrVelox transmitter:

1. Alignthekeywaysofthetransmitterandprobeconnectors.
2. Insertthetransmitterconnectorplugfullyintotheprobeconnectorreceptacle.
3. Securethetransmittertothetopoftheprobebytighteningthecouplingnut.
NOTE:Hand‐tightissufficient.Donotover‐tightenthecouplingnut.
NOTE:Neverforcetheconnectorstomate.Ifthereisresistance,stopandcheckforbentpinson
theprobeandforforeignmaterialinthefemalesocketsofthetransmitterconnector.Gently
straightenanybentpinsandclearanyforeignmaterialthatmaybefound.



Figure2.DirectMountInstallation
b.RemoteMounting
Whenitisnotpracticaltodirect‐probemounttheCorrVelox transmitter,theunitcanberemote
mountedinstead.Inthiscasetheinstrumentismountedtoaseparatemountingpoleusingthe
optionalRemoteMountingHardwareKit.ThetransmitteristhenconnectedtotheERprobeviathe
optionalprobeextensioncable.Whenpossible,thetransmittershouldbemountedwithin10’(3m)of
theprobetokeeptheprobecablingshortandminimizesignaldegradation.

2.PowerandDataConnections

a.MakingConnections
TheRS‐485connectionsaremadeviatheexternal6‐pincircularconnectorCN1asshowninFigure3.
Thishermeticallysealedconnectorpreventsmoistureingressandeliminatestheneedforinternal
wiringbyanoperator,thusreducingtheriskofphysicaldamagetothecircuitboard.

AlignKey
Insert
Connector Tighten
CouplingNut
12 3

6



Figure3.RS‐485Connector
Tofacilitatewiring,athreefoot(1meter)wiringharnessisprovided.Thiswiringharnessconnects
directlytothe6‐pinconnector,andextendstoanearbyjunctionbox(notincluded)tomakethe
necessarypoweranddatawiringconnectionsfromthecontrol(DCS/PLC)system.



Figure4.CorrVelox TransmitterWiringHarness
NOTE:DonotconnectcableshieldingtotheTransmitter.Theshieldmustremainfloatingatthe
Transmitter.

ThemaximumpermissiblelengthofthefieldwiringbetweentheCorrVelox transmitterandthe
controlsystemisdeterminedbythecontrolsystemsupplyvoltage,theelectricalresistanceofthe
cableandtheloadofthecontrolsysteminput.IftheTransmitteristobeinstalledinasafearea,refer
tosectionc.SafeAreaInstallationfordetails.IftheTransmitteristobeinstalledinahazardousarea,
refertosectiond.HazardousAreaInstallation.

b.Grounding

TheCorrVelox transmitterenclosureisgroundedinternallythroughthewiringharness,butan
additional,externalgroundingterminalisprovidedaswell.Theenclosureshouldbegrounded
properlyusingtheexternalgroundingterminaltoensuresafeoperation.

ConnectorCN1
(PowerandData)
JunctionBox
(NotIncluded)
Wiring Harness

7

c.SafeAreaInstallation

TheCorrVelox transmitterisapprovedforuseinhazardousareas,butcanbeusedinnon‐
hazardousareasaswell.Forbasicsafeareawiringinformationrefertothecircuitdiagramshownon
page22.


CAUTION:Whenusedinnon‐hazardousareas,equipmentmustbesuppliedwithapre‐approvedpower
supplyunitorapprovedequipmentwhichmeetstheentityparametersshownbelow.

Thepre‐approvedequipmentmustbecertifiedtotheelectricalsafetystandardsforequipmentin
ordinarylocations(forexample,EN/IEC/CSAUL61010‐1orEN/IEC/CSAUL60950‐1).Failuretomeet
theserequirementswillvoidtheintrinsicsafetycertificationoftheequipmentandprohibititsfuture
useinhazardousareas.


d.HazardousAreaInstallation

CAUTION:Thissectionprovidesgeneralguidelinesforhazardousareawiring.However,regardlessof
anythingstatedhere,theCorrVelox transmittermustbeinstalledinfullcompliancewiththecontrol
drawinglocatedonpage21andallofthelocalarearequirements.

Input supply terminal (Stand-Alone)
Input supply terminal (Multi-Drop)
Connector CN1 pins A & B (J2 on PCB):
Ui = 23 Vdc
Ii = 88.2 mA
Pi = 0.52 W
Ci = 0
Li = 0
RS-485 channel at each line
Connector CN1 pins D & E (J9 on PCB):
Ui = 3.7 Vdc
Ii = 225 mA
Pi = 0.206 W
Uo = 5 V
Io = 51 mA
Po = 0.064W
Input supply t
e
rminal, R
S
-
485 termina
l
and connector CN2 (combined)
Ci = 68uF
Li = 0
Co = 32uF
Lo = 0.14 mH
Probe connector CN2 (J1 on PCB):
Uo = 5 V
Io = 503 mA
Po = 0.7 W
Connector CN1 pins A & B (J2 on PCB):
Ui = 23.6 Vdc
Ii = 352.8 mA
Pi = 2.3 W
Ci = 0
Li = 0
RS-485 channel at each line
Connector CN1 pins D & E (J9 on PCB):
Ui = 3.7 Vdc
Ii = 225 mA
Pi = 0.206 W
Uo = 5 V
Io = 51 mA
Po = 64 mW
Input supply t
e
rminal, R
S
-
485 termina
l
and connector CN2 (combined)
Ci = 68uF
Li = 0
Co = 32uF
Lo = 1.2 mH
Probe connector CN2 (J1 on PCB):
Uo = 5 V
Io = 352.8 mA
Po = 0.44 W

8


CAUTION:WhenusedinHazardousareas,equipmentmustbesuppliedwithapre‐approvedpower
supplyunitorapprovedequipmentviaacertifiedintrinsicallysafebarrieroragalvanicallyisolated
barrier)withtheentityparameterslistedonthepreviouspage.


SpecialConditions

1.Probedielectricrating<500Vr.m.s.Donotexceed.
2.Probecannotbeinstalledintheexplosiondustatmosphere(GroupIII).
3.Networked(“daisy‐chained”)arrangementnotforuseinGroupIIC/IIICenvironment.
4.Maximum32transmittersareallowedinthedaisy‐chainarrangement.


Wheneveranelectricallydrivensensorormeasuringdeviceisusedinapotentiallyexplosive
environmentthemeasuringsystemmustbeinstalledinsuchawaythatelectricalenergyiseither
effectivelyisolatedfromtheexplosiveenvironment(viaexplosive‐proofcontainers,cableconduits,
etc.)ortheamountofelectricalenergyproducedinthehazardousareamustbelimitedtoan
intrinsicallysafelevel.

LimitingelectricalenergyisthemostpracticalmethodofprotectingtheCorrVelox transmitter
whenitisinstalledinahazardousarea.IntheCorrVelox transmitter,electricalenergylimitsare
maintainedbytheuseofappropriatesafetybarriersinstalledinthepoweranddatawiring.Thesafety
barriersmustbelocatedinthesafeareaneartheboundarybetweenthesafeandhazardousareas.
Thesafetybarrierwillrepeatthesignalcurrentgeneratedbythetransmitterandwillrelaythesignal
tothedatareceivingstation.

Caution:WhenasafetybarrierisusedwiththeCorrVelox transmitter,thetransmitterwiring
connectionsmustbeconnectedtothesafetybarrier’shazardousareaterminals.Allotherconnections
mustbemadetothebarrier’ssafeareaterminals.

ThetypeofrepeatersafetybarriersusedwiththeCorrVelox transmitterdependsonthespecific
classificationofthehazardousenvironmentinquestion.However,theentityparametersmustmatch
thoseoftheCorrVelox transmitter.



CAUTION:Forhazardousareainstallations,themaximuminductanceandcapacitanceofthefield
wiringbetweenthesafetybarrierandthetransmittercannotexceedtheentityparametersofthe
selectedbarrier.





9

3.SetupandOperation

a.ProbeSettings

Theprobeselectionswitchesarelocatedonthetopleftcornerofthemainboardasillustratedin
Figure5below.TheseswitchesareusedtosettheERprobetype.Theyalsoallowtheinstrumentto
beplacedintoseveraltestmodeswhichoutputfixedvalues,allowingverificationoftheoutputsignal.
Table2givestheswitchsettingsforeachprobetypeandthevarioustestmodes.














Figure5.ConnectorandSwitchDetails

Switch1
Setting
Position
1 2 3 4
Operating
Positions
Wire Loop Off (↓)On (↑) On (↑) Off (↓)
Tube Loop/Flush On (↑) Off (↓)On (↑) Off (↓)
Cylindrical
*
Off (↓)Off (↓)On (↑) Off (↓)
MicroCorr Probes Off (↓) Off (↓) Off (↓)Off (↓)
Test
Positions
Zero Output (0) On (↑) On (↑) Off (↓)Off (↓)
Maximum Output
(1,048,575) Off (↓)On (↑) Off (↓)Off (↓)
Full Scale Sweep On (↑) Off (↓)Off (↓)Off (↓)
Maintenance
Position Service Registers * **On (↑)

Table2.ProbeSwitchSettings
*Cylindricalprobesettingisillustrated.
Switch1‐Probe
SelectionSwitch
(SeeTable2below)
PowerConnector
(J2)
ProbeCableConnector
DataConnector
(J9)
Switch2‐ RS‐485
ConfigurationSwitches
(SeeTable3below)

10

b.RS‐485CommunicationSettings

TheRS‐485configurationswitchesarelocatedonthetoprightcornerofthemainboardasillustrated
inFigure5.Theseareusedtosettheinstrumentaddress,baudrate,communicationprotocol,andto
enabletheterminationresistor.Table3givestheswitchsettingsforeachoftheseparameters,and
theyareexplainedinmoredetailbelow.

Switch2
Device
Address
Position
34567
1Off (↓)Off (↓)Off (↓)Off (↓)Off (↓)
2On (↑)Off (↓)Off (↓)Off (↓)Off (↓)
3Off (↓)On (↑)Off (↓)Off (↓)Off (↓)
4On (↑)On (↑)Off (↓)Off (↓)Off (↓)
5Off (↓)Off (↓)On (↑)Off (↓)Off (↓)
BaudRatePosition6On (↑)Off (↓)On (↑)Off (↓)Off (↓)
127Off (↓)On (↑)On (↑)Off (↓)Off (↓)
2400Off (↓)Off (↓)8On (↑)On (↑)On (↑)Off (↓)Off (↓)
4800Off (↓)On (↑)9Off (↓)Off (↓)Off (↓)On (↑)Off (↓)
9600On (↑)Off (↓)10On (↑)Off (↓)Off (↓)On (↑)Off (↓)
19200On (↑)On (↑)11Off (↓)On (↑)Off (↓)On (↑)Off (↓)
12On (↑)On (↑)Off (↓)On (↑)Off (↓)
Communication
Protocol
Position13Off (↓)Off (↓)On (↑)On (↑)Off (↓)
8914On (↑)Off (↓)On (↑)On (↑)Off (↓)
ModbusASCIIOn (↑)Off (↓)15Off (↓)On (↑)On (↑)On (↑)Off (↓)
ModbusRTUOff (↓)Off (↓)16On (↑)On (↑)On (↑)On (↑)Off (↓)
SerialASCIIOn / OffOn (↑)17Off (↓)Off (↓)Off (↓)Off (↓)On (↑)
18On (↑)Off (↓)Off (↓)Off (↓)On (↑)
TerminationPosition19Off (↓)On (↑)Off (↓)Off (↓)On (↑)
Resistor1020On (↑)On (↑)Off (↓)Off (↓)On (↑)
ActiveOn (↑)21Off (↓)Off (↓)On (↑)Off (↓)On (↑)
InactiveOff (↓)22On (↑)Off (↓)On (↑)Off (↓)On (↑)
23Off (↓)On (↑)On (↑)Off (↓)On (↑)
24On (↑)On (↑)On (↑)Off (↓)On (↑)
25Off (↓)Off (↓)Off (↓)On (↑)On (↑)
26On (↑)Off (↓)Off (↓)On (↑)On (↑)
27Off (↓)On (↑)Off (↓)On (↑)On (↑)
28On (↑)On (↑)Off (↓)On (↑)On (↑)
29Off (↓)Off (↓)On (↑)On (↑)On (↑)
30On (↑)Off (↓)On (↑)On (↑)On (↑)
31Off (↓)On (↑)On (↑)On (↑)On (↑)
32On (↑)On (↑)On (↑)On (↑)On (↑)

Table3.RS‐485ConfigurationSwitchSettings




11

i.BaudRateandDefaultCommunicationParameters

ThedefaultcommunicationparametersfortheCorrVelox transmitterareprovidedinTable4
below.Ifnecessary,thebaudratecanbechangedusingPositions1and2ofSwitch2,asillustratedin
Table3.

Modbus
RTU
Modbus
ASCII
Serial
ASCII
ParameterValueValueValue
BaudRate19200192002400
DataBits878
ParityEvenEvenEven
StopBits111
ResponseTimeOut3000mS3000mS3000mS
PollingInterval1min1min1min
RTSToggleActiveActiveActive
RTSDisableDelay1mS1mS1mS
Table4.DefaultCommunicationParameters

ii.DeviceAddress

Upto32CorrVelox transmittersmaybeconnectedinamulti‐dropnetwork(“daisy‐chained”)using
asinglecablerun.However,eachtransmittermustbesettoauniquedeviceaddresstoavoid
conflicts.ThisisdoneusingPositions3through7ofSwitch2,asillustratedinTable3.

CAUTION:Besuretoobservetheappropriategasgroupratinglistedonpage3forstand‐aloneor
multi‐dropoperation.


iii.CommunicationProtocols

TheCorrVelox transmitteroffersuser‐selectableRTUorASCIIcommunicationprotocols,givingthe
unitabroaderrangeofcompatibility.ThecommunicationprotocolissetusingPosition8ofSwitch2,
asillustratedinTable3.

iv.TerminationResistor

Toensureproperoperation,theRS‐485networkmustbeterminatedproperlywithatermination
resistor.Tofacilitatethis,eachCorrVelox transmitterhasabuilt‐in120terminationresistorthat
canbeswitchedonoroffusingPosition10ofSwitch2.Onceallunitshavebeeninstalled,besureto
enabletheterminationresistorofthelastunitinthenetwork.Theterminationresistorsofallother
transmittersshouldbeturnedoff.







12

v.DataRegisters
Table5liststhedataregistersoftheCorrVelox transmitter.DataRegister40024and40025
transmittedfromthetransmitteristhedirectprobereadingvalue.

NoRegisterAddressDescription
440024DACValue(Low)
540025DACValue(Hi)

Toaccessallotherregistersformaintenancepurpose,theSwitch1,Position#4(Maintenance)should
beturnedon.

NoRegisterAddressDescription
140001DeviceStatus
240002DeviceAddress
340003BaudRate
440024DACValue(Low)
540025DACValue(Hi)
640026ProbeSwitchSetting
Table5.ModbusDataRegisters




c.CalibrationandTesting

i.Calibration

TheCorrVelox transmitterisfullycalibratedwhenshippedfromthefactory.Thecalibration
settingsarefixedtoavoidaccidentalchangewhichcouldresultinerroneousdata.Nofieldcalibration
isrequired.However,itisimportanttotesttheunituponinstallation,andduringperiodic
maintenanceinspections,toensuretheunitisoperatingproperly.

ii.Testingoutputzeroandspan

TheCorrVelox transmitterProbeSelectionSwitches(page9)offerthreetestsettingsthatallowthe
unittobeplacedintovariousdiagnosticmodesasfollows:

1) ZeroOutput–Forcesadigitaloutputof0.
2) MaximumOutput–Forcesadigitaloutputof1,048,575.
3) OutputSweep–Causestheoutputtocontinuallycyclefrom0upto1,048,575.

Thesetestmodescanbeusefulwhentroubleshootingcommunicationproblemsbetweenthe
transmitterandtheDCS/PLCsystem.





13

iii.TestingtheCorrVelox transmitterwiththeMeterProver
AMeterProverisprovidedtoallowroutinechecksoftheCorrVelox transmitter.TheMeterProver
simulatesaWireLooptypeprobeatafixedvalue.TotesttheunitwiththeMeterProver:

1) Disconnectpower.
2) DisconnecttheCorrVelox transmitterfromtheprobe(oriftheunitisremote‐mounted,
disconnecttheprobeextensioncablefromtheprobe.)
3) ConnecttheMeterProvertotheprobeconnectorstem(ortotheprobeextensioncableifthe
CorrVelox transmitterisremote‐mounted.)
4) LoosentheEnclosureLockScrew.
5) Unthreadandremovethetransmittercover.
6) ChangetheProbeSelectionSwitchestotheWireLoopposition(seepage9.)
7) Reconnectpowerandallowtheinstrumenttomeasureforseveralminutestostabilize.
8) Afterseveralminutesobservethetransmitteroutput.Theoutputshouldcloselymatchthe
valueprintedontheMeterProverlabel.

IfthetransmitteroutputmatchestheMeterProvervalue,youmayreturntheProbeSelection
SwitchestotheirprevioussettingandreconnecttheCorrVelox transmittertotheprobe.Ifthe
transmitteroutputshowsasignificantdifferencecomparedtotheMeterProvervalue,further
troubleshootingmayberequired.Refertopage17fortroubleshootingorcontactthefactoryfor
furtherassistance.

BesuretoreinstalltheenclosurecoverandtightentheLockScrewwhenputtingtheCorrVelox
transmitterbackintoservice.


d.InterpretingData
i.MetalLoss
TheCorrVelox transmittermeasurestheMetalLossofanERprobeandconvertsthatvaluetoa
digital20‐bitRS‐485Modbusoutput.ThisoutputisdirectlyproportionaltothecumulativeMetalLoss
oftheERprobeatanygiventime.Theoverallspanoftheoutputisproportionaltothelifeofthe
probeinuse,soforDCS/PLCprogrammingtheRS‐485Modbusoutputcanbescaledasfollows:

0=0mils(0%MetalLoss)
1,048,575=ProbeLifeinmils(100%MetalLoss)

TheProbeLifecanbefoundinTable1andisalsolistedontheMetalSamplesprobetag(asthe
“Multiplier”.)



Figure6.MetalSamplesProbeTag


14

Figure7illustratestherelationshipbetweenthedigitaloutputandMetalLoss.Inthisexamplea
probewitha10‐millifeisassumed.However,theXaxiscouldbechangedtorepresentanyProbeLife.
Figure7.OutputRelationship
Asseenhere,thetransmitteroutputbeginsat0foranewprobe(zeroMetalLoss)andincreasesas
theprobeelementcorrodes,eventuallyreachingamaximumof1,048,575whentheprobesensing
elementhasbeencompletelyconsumedbycorrosion(inthiscase,10milsofMetalLoss.)Atthistime
theprobehasreacheditsend‐of‐lifeandmustbereplaced.


ii.CalculatingCorrosionRate


Asexplainedpreviously,ERprobesandinstrumentsreportMetalLoss.However,thevaluethatisof
ultimateinterestisCorrosionRate.TheCorrosionRateisessentiallyMetalLossovertime,sothe
CorrosionRatecanbecalculatedusingthefollowingformula:
CorrosionRate󰇛mpy󰇜  ∆MetalLoss󰇛mils󰇜
∆Time󰇛days󰇜  365

where:
∆MetalLoss(mils)isthedifferencebetweentwoMetalLossreadings

 Time(days)isthetimedifferencebetweenthosetworeadings

Itisacommonpracticetoprogramthisformulaintothecontrol(DCS/PLC)systemandhaveit
calculateCorrosionRateonacontinualbasisfromtheMetalLossdata.Thechallengeindoingthisis
selectinganappropriatetimeinterval.Usinganintervalthatistooshortmaygiveerraticresults,
whileselectinganintervalthatistoolongmaygiveresultsthatareinsensitivetosystemupsets.The
idealtimeperioddependsonmanyfactors,andwillvaryfromsystemtosystem.Itmaytakesome
trialanderrortosettleonthebesttimeperiodforyourinstallation.
0
262144
524288
786431
1048575
0.0 2.5 5.0 7.5 10.0
RS‐485ModbusOutput
MetalLoss(mils)
New
Probe
Probe
Consumed

15


InsomecasesitmaybenecessarytoreviewtherawMetalLossdataandmanuallyapplythe
CorrosionRateformulatoperiodsofinterest.Forexample,lookatthegraphbelowandseehow
muchthecalculatedCorrosionRatecanvarydependingonthetimeperiodused.

Figure8.CorrosionRatescalculatedfromMetalLossdata
Whileeachoftheresultsisvalidfortheselectedtimeperiod,theoneofmostinterestisthevalueof
11.81mpywhichrepresentssometypeofsystemupset.WhentheCorrosionRateiscalculated
automaticallyonapre‐selectedtimeperiod,thereisnoguaranteethattheselectedtimeperiodwill
alwayscoincidewithsystemupsetssuchasthis.Thatiswhymanualreviewandinterpretationof
MetalLossdataisalsohelpful.

16

e.Commissioning

OncetheCorrVelox transmitterhasbeeninstalled,tested,andproperlyconfiguredfortheprobein
use,itcanthenbeclosedandputintoservice.First,performonelastvisualinspectiontoensurethatall
electricalconnectionsaresecureandthattheenclosureo‐ringisinplaceandisingoodcondition.Then
threadtheenclosurelidontothebasefully.Oncethelidhasbeenthreadedintoplace,tightentheLock
Screwtopreventunauthorizedtampering.



Figure9.EnclosureLockScrew

CAUTION:TheLockScrewontheinstrumentbasemustbetightenedsecurelytopreventunauthorized
personnelfromopeningthe
Corr  Velox transmitterandensurethattheintrinsicsafetyisnotviolated.
Onlyqualifiedpersonnelshouldbeallowedtoinstall,operate,andmaintenancethe
Corr  Velox
transmitter.


C.Maintenance
Onceinstalled,theCorrVelox transmitterrequireslittlemaintenance.However,itisimportanttoverifythe
followingitemsperiodicallytoensurecontinuedsafeoperation.

CAUTION:Beforeperforminganytestsormaintenanceonthe
Corr  Velox transmitter,ensurethatall
hazardousarearequirementsaremet.


InspectionItemFrequency
Inspecttheenclosureo‐ringforanysignsofdamage.Replaceasnecessary.Annually
Inspecttheprobeconnectoro‐ringforanysignsofdamage.Replaceasnecessary.Annually
Inspecttheexternalelectricalconnectionsforsignsofcorrosion,mechanicaldamage,or
foreignmatterthatcouldcausedamageorcauseanelectricalshort.Cleanasnecessary.
Annually
Ensurethatthelockingscrewisinplaceandissecure.Annually
TheCorrVelox transmitterenclosureismadeofcorrosion‐resistant316stainlesssteel.
However,itshouldstillbecheckedperiodicallyforanysignsofcorrosion.
Annually
Checkforanysignsofmoistureingresswithintheenclosure.Annually
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ContactMetalSamplesforreplacementpartsorifinstrumentrepairisnecessary.
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