Product data sheetIP201, Rev AA February 2009 Level

Mobrey ultrasonic Liquid level detection systems

DescriptionUltrasonic liquid level switches are used in industrial processes, to detect high or low liquid levels.

Operation is achieved using the time proven principle of ultrasonic transmission between two crystals. Liquid presence is detected by virtue of its bulk. Liquid droplets, condensation or foaming are ignored.

Control electronics are available as standard or with ATEX intrinsically safe hazardous area approval with options including lamps to indicate sensor status, time delays and circuits to detect wiring faults.

Features• Nomovingparts• Simpleinstallation• ATEXHazardousareaapproval• Ignoresfoams• Unaffectedby: RF Interference Conductivity Droplets Most coatings Liquid colour/opacity

ContentsSystemdescription................................................2

Choice of sensor................................................... 2

Choice of system and control unit......................... 3

Ultrasonic point level sensor dimensions.............. 4

Interface detection and sludge measurement...... 5

Standardindustrialcontrolunits........................... 6

Electrosensor systems......................................... 7

Ultrasonic liquid level sensor selection................. 9

Ordering information............................................. 10

System description AMobreyultrasonicliquidlevelcontrolcomprises:•Atankmountedsensorcontainingtransmitterand receiver crystals•AnRFsensordriveanddetectorelectroniccircuit, which may be integral with the sensor or mounted adjacent to the sensor depending upon vessel conditions or access considerations.•Acontrolunitmountedremotelytomonitorthe sensor state and provide the required switching function

Choice of sensorMobrey gap sensorsMobrey gap sensor systems are active when there is a liquid present between the transmitter and receiver crystals of the sensor. In this way, absence of liquid, or damage to cabling will result in a low level being indicated.

Typical applications•Pumpprotection•Vesselemptyprotection•Pumpcontrol

Ultrasonic sensor operation can be adversely affected by the presense of excessive aeration, solids or foam in the liquid. If you have an application query contact Mobrey for expert advice on the selection of a suitable liquid level detection system.Sensorsmaybemountedinanypositiontosignalliquid presence.

Mobrey gap sensor: General purpose failsafe low level

Sensorwithadjacentamplifier

Sensorwithheadamplifier

Control room electronics

a)SensorinairThe ultrasonic signal will not reach receiver crystal

b)SensorinliquidThe ultrasonic signal reaches receiver crystal

Control unitRelay output is energised- NORMALSTATE

Control unit

Relay output is de-energised- ALARMSTATE

Signalisreceived

Transmitter crystal

Receiver crystal

Nosignalisreceived

MEScontrolbox

SAFEHAZARDOUS

2 wire twisted pair

Supplyrelay

Choice of system and control unit

Safe area use only

The MCU200 control unit provides simple, economical control electronics for mounting on site near the tanks containing the appropriate ultrasonic sensor. The control unit has a sensitivity potentiometer to adjust for sensor and liquid type.

MCU200 offers in addition a selectable time delay, earth continuity checking between sensor and control unit, and LED's to indicate sensor state. MCU200 has a DPCO relay output and is suitable for use with all Mobrey sensors.

WallmountingIP65polycarbonateenclosureConnection between sensor and control unit is by up to 50m of dual co-axial cableFailure of sensor or breakage of co-axial cable earth loop will cause an alarm condition and light the fault LED.(subjecttoconfiguration).

StandaloneelectronicsSimpletwistedpaircablebetweensensorandcontrolunit up to 1000mSafeorhazardousareauseFailure of sensor or cabling will cause an alarm condition and light the fault LEDAdditional fault relay activated on fault condition

Intrinsically safe ATEX II 1 G EExia IIC T4

Selectfromthe2systemsbelowtheonewhichmeetsyourneeds,thenturntopage9andselectasensortosuitthe liquid in the vessel and your application.

Mobrey Electrosensor systems provide a cost effective method of level detection and control where high system integrity coupled with low cost installation is required.

Ultrasonicsensorsarefittedwithhead-mountedoradjacent electronics which are then connected back to control room electronics using simple twisted pair wiring.Sensorsmaybesettooperateeitherwhenwetordryandhaveafieldadjustablesensitivitypotentiometer and status LED.AllsensorsarebuilttoISstandardsandmaybeusedin safe or hazardous areas.

Standard industrialIndustrial control unit

High integrity / Hazardous AreaElectrosensor

Gap sensor

Supplyrelay

Across pipe sensor Interface

Sensortype442SDAcross pipe

Designorduty: PipelinesLiquidtype: Cleanormaybeused for sludge detectionTemperature: -70oC to +150oC

Sensortype433SDStainlesssteel

Designorduty: SludgeorinterfaceLiquidtype: Viscousorwithsolids in suspensionTemperature: -70oC to +50oC

Sensortype402SDStainlesssteel

Designorduty: ChemicalinterfaceLiquidtype: Clean,viscouswith solids Temperature: -70oC to +150oC

Ultrasonic point level sensors : Dimensions

WHshowsapproimateswitchinglevelwithsensorhorizontalWVshowsapproximateswitchinglevelwithsensorverticalExtendedlengthversions:MaxA=3000mmvertical,915mmhorizontal,whereAisthemeasurementfromthemounting thread run-out to the nominal switching point.

General purpose

Sensor type 332 SDGeneral purpose stainless steelDesignorduty: StandardLiquidtype: CleanonlyTemperature: -70oC to +150oC

Sensor type 302 SDGeneral purpose stainless steelDesignorduty: StandardLiquidtype: Clean,minoraerationTemperature: -70oC to +150oC

51

27

WV

Ø22

¾"BSPT

1324

57.5

23 8.5

WV

Ø286

WH17

1"BSPT

258

25 152 26

Ø22

¾"BSPT

WH11

WV

61

102

30 30

11

WH

Standardgap=150mm

Specifygap50 to 450mm

¾"BSPT

7925

Ø22

¾"BSPT

WH

Sensor technical data

Technical data for all sensors•Powerconsumptionlessthan10milli-wattsatsensor•CableentrytosensorisIP65.•MTBFofstainlesssensorsfoundtobe0.15x10.6/hr.•Tempshockrange-70°Cto+120°Cifapplicable.•Mechanicalshock-testedtowithstand20Gmin.•Nonoperationaltemperaturelimit175°Ctypical.

Sensor cable•StandardisP.T.F.E.insulateddualcoaxialwithPVC sheath.•Minimumbendradiusis35mm.•Radiationresistantcable,suitablefor100Megarads, may be supplied to order.

StandardsensorsRepeatability (mm)Max. pressure (d) (bar)Weight (gm)Standardfrequency(MHz)Standardcablelength

302 332 402 442 4332

105350

1-3.3/3.77

21055003.73

21053503.73

27040013

210535013

A24

¾"BSPT

13

51

Ø22WH13

WH11

WV

Interface detection and sludge measurement

Ultrasonic technology can be used to discriminate between immiscible liquids to indicate the interface and to detect and monitor suspended solids.

Interface detection For interface detection between immiscible liquids, two techniquesareavailable:ultrasonicattenuationandultrasonicreflection.Both techniques use standard Mobrey liquid level controlelectronicsystems.Suitablesensorsforinterface monitoring are typically the larger gap types i.e. 150mm upwards.

Ultrasonic attenuation is the reduction in energy ofthe beam as it is transmitted through the liquid. Viscousliquids,emulsionsandliquidswithentrainedsolids generally have a higher ultrasonic attenuation than low viscosity clear liquids such as water. When theattenuationdifferenceissufficient,theamplifiergain can be adjusted so that the ultrasound beam passes through the less attenuative liquid but is stopped by the more attenuative liquid. The output relay can then be set to monitor which liquid is in the gap.

When two immiscible liquids have similar attenuations the above method cannot be used, however it is likely that the velocity of ultrasound will be different. In this case a beam of ultrasound passing through theinterfacewillbereflectedandrefractedandifthesensor is arranged at a shallow angle the effect is that the transmitted beam tends to miss the receiver and is thus effectively attenuated.

Sensor in oilThe ultrasonic beam is attenuated and will not reach the receiver crystal

Sensor in waterThe ultrasonic beam reaches the receiver crystal

Headelectronics

Headelectronics

AirOil

OilWater

Receiver crystal

Transmitter crystal

An angle of 10 degrees is chosen and often this resultsintotalinternalreflectionofthetransmittedbeam. Thus when the interface is within the gap of the angled sensor, very little ultrasound reaches the receiver, but when the interface is above or below the sensor (ie in either liquid) then there is a large signal present. The control unit gain is set to actuate therelaywhentheinterfaceisinthegap.Notethiscondition will also occur if the upper liquid drains away andair(gas)isinthegap.Noteforfurtherinformationon suitability of this application consult our technical sales.

Suspended solids measurementSolidssuspendedinaliquidwillscatterultrasonicbeams, causing attenuation. This attenuation depends on the size and nature of the particles and for typical sewage sludges it is possible to use Mobrey ultrasonic systems to detect 1% to 15% w/w. Industrial slurries suchasfinepotteryslipscanoftenbemeasuredto65%,butcoarsegranularmaterialisoftenveryattenuative.LeafletIP250givesdetailsofMobreysludge measurement systems.

Interface and sludge monitoringTypically sensors with gaps of 150mm or larger are used for interface and sludge measurement. These sensors are standard types 402, 433 and the 442 (a pair of sensors for mounting across or along a pipe section).Specialflangedsensorswiththe10degreetilt built in are also available. Generally these sensors workat3.7MHzandarecompatiblewithElectrosensorelectronics or plant mounted MCU200 electronics.

Interface detection by attenuation

Headelectronics

Headelectronics

Air

OilWater

Receiver crystal

Transmitter crystal

OilWater

Air

Interface detection by reflection

Mobrey standard industrial control unit MCU200

•Simpleeconomicalcontrolunit•IP65enclosure• 115v/230vACor24vDC

Description The MCU200 control unit provides simple, economical control electronics for mounting on site near the tanks containing the appropriate ultrasonic sensor. The sensors provide liquid level detection, and are available in various materials and mechanical designs. (Seepage9).The control unit provides a relay output for external control or alarm functions according to whether the sensor is wet or dry. The MCU200 has a dual pole relay output energised when the sensor is wet, LED indicators, time delays and cable check facilities preselectable. The MCU200 will operate with all Mobrey ultrasonic sensors and can accept a voltage free contact input from another level switch to give a pump control function on the output relay.

Installation Mobreyultrasonicsensorsarenormallyfittedwithdual coaxial cable. This cable can be extended with suitablecoaxialextensionsupto50metres.SuitablecableispartNo.K178,ortwolengthsofcoaxtypeRG178 can be used.The coaxial cables are terminated in the control unit. The output cabling from the control unit comes from the relay output terminals as a wet/dry changeover switch. This can be used to trigger an alarm or provide an input into a control system.

Technical dataMCU200 Features SuitableforallMobreyultrasonicpointsensorsFrequency selection By switch on PC boardRelay Energised for sensor wet or dry selectable by switchLEDindicators Visiblethroughtheboxlid.Greenfornormal.Redforalarm.Selectableforwet/dry sensor as appropriate for the application.Amber LED for fault conditionGain potentiometer Fitted with scale and separate range switch to adjust for sensor type and site conditions.Responsetime Selectabledelayof0.5,2,8or30seconds.Delayselectablewettodryordrytowet.50 ms response in opposite directionSensorcablecheck Selectabletomonitorcoaxscreentosensorforcontinuity. Fault lights fault LED and sets relay to alarm stateAuxiliary input External closed circuit input to MCU200 latches the output relay to achieve pump control

Power supply(Selectorswitch)

Power consumptionRelay outputRelay ratingBox dimensionsBox ratingHolesforglandsFixingcentres(WxH)Fixing hole diameter

MCU201 MCU203110/120Vac 24Vdc220/240Vac earthed negative 6VA 0.1A DPCO 5Aat230V 200 x 120 x 75 IP65Polycarbonate 3off16mmdia, 188 x 88mm 4mm

• Features: SensorstatusLED Time delay Cable check Pump control

Safe area use only

Gap sensor

Co-axial cable

SupplyRelay

Electrosensor systemsDescriptionAn Electrosensor system comprises an ultrasonic sensor with head electronics either mounted directly on the sensor or in an adjacent wall mount box, and control room electronics. Connection between sensor electronics and control electronics is by standard twisted pair instrument cable, typically over distances up to 1000m.

Principle of operationThe twisted pair supplies a DC voltage from control electronics to the sensor. The current drawn by the sensor is used to signal the sensor state. This current signallingisdetectedbyatripamplifierinthecontrolelectronics.The control electronics include a fault monitoring circuit to detect if the current drawn is outside preset limits, such as would occur on cable breakage or short circuit. Electrosensor can be used in all areas of the plant.Someusersmayprefertoprovidetheirownsupply and alarm circuits. Electrosensorsarefullysystemcertifiedtoaccommodate this need, enabling connection to PLC orothercontrolcircuitsviastandardZenersafetybarriers when the sensor is in a hazardous area.

Control room electronics• Providesintrinsicallysafepowersupplytosensor electronics and detects sensor state. • OperatesoutputrelaysandfrontpanelLEDs• Monitorsplantwiringintegrity

MES3L/*Scontrol room unit

SpecificationCommonspecificationsDesign concept Will de-energise relay on loop current levels falling outside of preset limits (i.e. open or short circuit) All control room electronics have visible LEDs to indicate sensor and fault detection circuit status.LEDindicators 3off:Alarmrelayon,Alarmrelayoff,faultdetectedApproval ATEXII(1)G[EExia]IIC(MES2D/3Srequiresseparateexternalsafetybarriers ATEX II (1) G for connection to the sensor in a hazardous area.)Standaloneelectronics:MES3L/*S Operates one electrosensor or two sensors for pump controlAlarmrelayoutput Selectable:energisedforsensorwetorsensordryusingPCBswitch. When two sensors are connected, relay assumes a pump control function and PCB switch selectswhethertherelayisenergisedtofilloremptythetankbetweenthetwosensorsFault relay output De-energises on fault condition. PCB switch to select whether the fault condition also de-energises the alarm output relay.Relays(2) SPCO100VAmax/5Amax.Cableentry Viabasecutoutsthroughrubbergrommetstoterminalstrip.Voltage MES*L/1S:230Vac50/60Hz MES*L/2S:115Vac50/60HzOutputtosensor Mainspoweredunits:12vDCintrinsicallysafe,fullyfloating(galvanicallyisolated)Delay 0.5s wet to dry 50ms dry to wetAmbienttemp. 60oCPowerconsumption 8VAProtection IP20Power supply tol. AC mains +/- 10%

Ordering informationMES3L/1S:230VacMES3L/2S:115Vac

CurrentFAULT

WET

DRYmA

20

16

12

8

4

0O

scill

atin

g

Non-

osci

llatin

g

FAULT

Electrosensor head electronics

Head mounted (integral) electronicsMountedinatoughglassfillednylonenclosureweatherprooftoIP66/IP67theheadelectronicsdrivethe sensor and detect its state; either wet or dry.ConnectionisviatheM16cablegland(supplied).Removalofthehousingcoverreveals:• Adjustablegainpotentiometertosetthesensorto suit application conditions.• Modeselectorswitch.• Connectionsforcontrolelectronics.• LEDtoindicatesensorstate(visiblethrough window in end cover)

Hazardousarea ElectrosensorsareapprovedintrinsicallysafeATEXII1GEExiaIICT4(-40°C< Ta <+85°C)approval orT5(-40°C< Ta <+40°C)andcanbeusedwithcontrolroomelectronics(Page9)orusedin an intrinsically safe systemPowerinput: 12-24VDCfromassociatedMEScontrolroomelectronicsorothersuitablyprotectedsourceSensing: Drawseither8or16mAonacurrentloopdependentonsensorstateandmodeswitchsettingModeselector Giveschoiceofcurrentlevelforsensorstate.Wouldtypicallybesetfor16mAwithsensor switchoscillating(i.egapsensorwet,Hi-sensdry)Outputselection Bothtypesofheadamplifierhaveatransistoroutputonathirdterminal,suitableforsignalling to a PLC or similar device. This transistor output switches upto 30mA at the supply line voltage onto the third wireAmbienttemp. -40°Cto+60°CEarthing Headelectronicsarefloatingwithrespecttosensorbody.Sensorbodymaybeearthed through tank connection.Plantcabling Standardtwistedpairinstrumentcablerecommendedwithscreen(screennotconnectedat head electronics). Maximum loop resistance 30 ohms. Cable parameters must conform to ATEX requirementsUsers own Electrosensors on this page can be used in any intrinsically safe systemelectronics The user must ensure that suitable safety barriers are used.

Specification

Mostofthesensorsonpage4canbespecifiedwithElectrosensorelectronics.1MHzsensorswith dual screwedfittngscanbespecifiedwithheadmountedelectronics housed in a tough nylon enclosure integral withthesensor.Afieldadjustablegainpotentiometerand an LED indicator, visible through the end cover to show sensor status are provided. A selector switch tosetthe16mAsignaltooccureitherwiththesensorwetordryisalsoprovided.AterminalwithPNPoutputallows direct connection to a PLC input via a third signal wire.Sensorheadelectronicsarealsoavailableinanadjacent wall mounting enclosure, for use with any 1MHzor3.7MHzsensor.Theseelecronicsareused where it is not possible or desirable to mount the electronics directly on the sensor. Connections between adjacent electronics and sensor is by dual coaxial cable (maximum length 10m).

The Electrosensor model no. as selected from page 9 includes head electronics, code SSH.

Headelectronics Adjacentelectronics:MES3AI

Suitablesensormustbe selected from page 9codeU8Honly

Adjacent mounted electronicsThe sensor drive and detector electronics are enclosedinawallmountedIP65polycarbonateboxwhich is wired to the sensor using dual co-axial cable (maximumlength10m).Connectionisvia2M16cableglands(supplied).Removaloftheboxlidreveals:• Sensorfrequencyselectorswitch(1MHzor 3.7MHz)• Coarseandfinegrainadjustmenttosetthesensor to suit application conditions.• Modeselectorswitch.• Connectionsforsensorandcontrolelectronics.• Outputselectorswitchfor8-16mAcurrentloop operation. If PLC operation is selected, current drawn is set to approximately 8mA in both sensor states (wet or dry).• LEDtoindicatesensorstate(visibleonlywhenbox lid removed).

CODE

80U8HSSH

Compatible control system Control boxes MCU ElectrosensorMESElectrosensorMES

Standardwith3mCable,nonapprovedATEXapproved.Forusewithadjacentheadamplifier*ATEXapproved.Fittedwithintegralheadamplifier

Notpermissiblewith442SD

SensorcompatibilitywithMobreySystems

CODE E

1-5

StandardOptionsSensorsavailableinextendedlengthversionsSpecifydimension‘A’(Seepage4)whenorderingForhorizontalsensormounting,Max‘A’=915mmForverticalsensormounting,Max‘A’=3000mmSpecifiessensorgapsizeon433Type:1=100mm:2=200mm3=300mm:4=450mm 5=150mm

Permissible with 302 only

433 only

Notpermissiblewith332402, 442, 433

302, 332, 402, 442

CODE SpecialOptionsX123or AsuffixintheformX***maybeusedwhereaspecialoptionissuppliedM1 When ultrasonic crystals with a non-standard operating frequency are supplied, the suffixusedwillbeintheformM*.

302SD80(Thesecharactersonlyusedifrequired)

FulldetailsofMobreyultrasonicsensorsforuseinsludgeblanketlevelorsludgedensitymeasurementsaregiveninleafletIP250

Notes:Carbondioxide(C02):ultrasonicgapsensorswillnotoperateinliquidC02,whichishighlyattenuative.

�� � �

For pressure above 50 bar, always consult factory before specifying.

Most sensors are available withflangemounting.Consultfactory for details.

Sensoroperationmaybeupset by highly aerated or heavily contaminated liquids. Consult factory if in doubt.

Ultrasonic liquid level sensor selection

Fitting

1"BSPTdual¾"BSPTdual ¾"BSPTdual

¾"BSPTinside

¾"BSPTdual

Wetside Material 316st.st(cast)316st.st(cast) 316st.stl(cast)

316st.st(cast)

316st.st(cast)

Design or Duty StandardStandard Interface duty

Interface duty

Across pipeline

Code

332SD302SD 402SD

433SD

442SD

Liquid Type Clean Clean Clean

Clean

Clean

Temperature -70°Cto+150°C-70°Cto+150°C

-70°Cto+150°C

-70°Cto+50°C

-70°Cto+150°C

Pressure

56b105b

105b

105b

105b

SensoractiveWetWetWet or clearWet or clearWet or clear

Ordering information - control room electronics

Sensor Page9 Selecttype***SDU8H*Headamplifier MES3AI

Sensor/amplifier Page9 Selecttype***SDSSH*

Ordering information - control room electronics

Ordering information - control room electronics

Electrosensor ordering information

Electrosensorfittedwithheadamplifier

Electrosensorwithadjacentamplifier

MES3Lcontrolroomelectronics

Customers own control electronics

Zenersafety barriers

HAZARDOUS AREA SAFE AREA

� � � � �

MES MobreyElectrosensor Code Approvals 3 Intrinsically safe (type L enclosure only) Code Enclosure L Standaloneenclosure Code Voltageinput 1 230VacMES3Lonly 2 115VacMES3Lonly Code Relay output S SPCO

MES 3 L/ 1 S Typicalmodelnumber

International:Emerson Process ManagementMobrey Measurement 158EdinburghAvenue,Slough,BerksUKSL14UET+44(0)1753756600F +44 (0)1753 823589www.mobrey.com

The Emerson logo is a trade mark and service mark of Emerson Electric Co.Mobrey is a registered trademark of Mobrey Ltd.All other marks are the property of their respective ownersWereservetherighttomodifyorimprovethedesignsorspecificationsofproductandservicesatanytimewithoutnotice.

Product data sheetIP201, Rev AA February 2009Level