Application Guide AG300 Issue 14 - BEKA · Application Guide AG300 Issue 14 BA300E & G Series intrinsically safe 4/20mA loop powered indicators

Application GuideAG300 Issue 14

BA300E & G Seriesintrinsically safe 4/20mAloop powered indicators

http://www.beka.co.uk/

Contents

1. Introduction

2. Description

3. Intrinsicsafetycertifications

3.1 IECExcertification

3.2 ATEXcertification

3.3 USandCanadiancertification

4. Description of ATEX & IECEx gas certification

4.1 Certificationlabel

4.2 Zones, gas groups and T rating

4.3 4/20mA input

4.4 Optionaldisplaybacklighting

4.4.1 Loop powering

4.4.2 Separately powering

4.5 Optional alarms

5. Description of ATEX & IECEx dust certification

5.1 Certificationlabel

5.2 Zones, dust groups and surface temperature

6. Description of North American certification

6.1 FMcertificationofBA304Eand BA324E

6.2 FMcertificationofBA307,BA308E, BA327EandBA328E

6.3 ETLandcETLcertificationof BA304G & BA324G

7. Hazardous areas applications

7.1 4/20mAloopdesign

7.2 Remoteindication

7.3 Displaybacklight

7.3.1 Looppoweringthe backlight

7.3.2 Separatelypoweringthe backlight

7.4 OptionalAlarms

8. Special functions

8.1 Squarerootextractor

8.2 Lineariser

8.3 Tare

9. Rugged panel indicator applications

9.1 Installation in an Ex e panel enclosure located in Zone 1 or Zone 2

9.2 Installation in an Ex p panel enclosure located in Zone 1 or Zone 2

9.2.1 Ex px panel enclosure

9.2.2 Ex pz panel enclosure

9.2.3 Ex py panel enclosure

9.3 Installation in an Ex t panel enclosurewithinZone21 or Zone 22

9.4 Installation in USA and Canada

10. Loop powered 4/20ma Rate Totalisers

1. INTRODUCTIONThe first BA300 series intrinsically safe loop powered4/20mAindicatorwas introduced in1984,sincethentherangehasbeencontinuouslydevelopedthroughtheB,CandDmodels.This edition ofApplicationGuideAG300describestheuseofthefourthgenerationintrinsicallysafeE & G instruments including the rugged stainless steelpanel mounting models introduced in 2014.

For applications in Zone 2 hazardous areaswithout theneed for an intrinsically safe interface such as a Zenerbarrierorgalvanicisolator,ExnAcertifiedfieldandpanelmounting models are available. SeeApplication GuideAG310 for details.

TheBA500seriesduplicatesthecompleterangeoffieldand panel mounting models for safe area applications.

2. DESCRIPTIONTheBA300E&Gseriesindicatorsarelooppoweredbythe4/20mAcurrenttheyaremeasuringanddonotrequireanadditionalpowersupply.Allthemodelscanbecalibratedtodisplay the4/20mA inputcurrent inengineeringunits,theymaybeusedinnewinstallationsandarebackwardscompatible allowing them to replace earlier B, C andDsuffixmodels.

Fig1showsasimplifiedblockdiagramofaBA300seriesindicator.The4/20mAinputcurrentflowsthroughresistorR1andforwardbiaseddiodeD1.ThevoltagedevelopedacrossD1,which is relativelyconstant, ismultipliedandused topower theanalogue todigital converterand theliquid crystal display.The voltage developed acrossR1,whichisproportionaltothe4/20mAinputcurrent,providestheinputsignalfortheanaloguetodigitalconverter.Thistechnique allows all models to drop less than 1.2V inthe4/20mAloop,andenables the two input terminals tocomplywiththerequirementsforsimple apparatus.

Less than1.2V

4/20mAinput

2

3

4

R1

D1

8

9

10

11

1

12

13

Powersupply

alarm 1

alarm 2

Optionalbacklight

Optionalalarms

Analogueto digitalconverter

++

+

14

Common

Loop powered -

-Separatelypowered

Field mountingmodels only

5

6

Fig1SimplifiedblockdiagramofBA300EorGintrinsicallysafe indicator.

ThefeaturesofalltheintrinsicallysafeBA300E&Gmodels aresummarisedinTable1.Detailedspecificationsforeachmodel are contained in individual datasheets availablefromBEKAassociatessalesdepartmentor theymaybedownloadedfromtheBEKAwebsiteatwww.beka.co.uk/datasheets.html.

3. INTRINSIC SAFETY CERTIFICATIONSThe BA300E & G series indicators have internationalintrinsicsafetycertificationsallowingthemtobeinstalledingasanddusthazardousareasworldwide.

3.1 IECExcertificationAllmodelshaveanIECExCertificateofConformityissuedbyCertificationBodyIntertekTestingandCertificationLtd.IECExcertificates,whicharebasedon international IECstandards,arealreadyacceptabledirectlyor indirectly inlargepartsoftheworld.

3.2 ATEXcertificationNotified Body Intertek Testing and Certification Ltd hasissuedallmodelswithanEC-TypeExaminationCertificateconfirmingcompliancewithharmonisedBSENstandardswhich have been used to confirm compliance with theEuropeanExplosiveAtmospheresDirective2014/34/EU.The instrumentscarry theCommunityMarkand,subjectto localcodesofpractice,maybe installed inanyof theEuropean Economic Area (EEA) member countries.ATEX certificates are also acceptable in Switzerland,Iceland,Liechtenstein,NorwayandTurkey.TheEuropeanCommission’s Blue Guide lists the member states,overseas countries and territories that have adoptedharmonisationlegislation.

BritishBSENstandardsarebasedon international IECstandards,thereforeATEXandIECExcertificatesnowusesimilar terminology and for these indicators are virtuallyidentical.

ThisguidedescribesATEXandIECExinstallationswhichconformwithIEC/BSEN60079-14Electricalinstallationsdesign,selectionanderection.WhendesigningsystemsforinstallationoutsidetheUK,thelocalCodeofPracticeshouldalwaysbeconsulted.

3.3 USandCanadiancertificationAllmodelshavecertificationallowinginstallationintheUSAand Canada which have been issued by two NationallyRecognised Testing Laboratories NRTLs, FM and ETL.FortheUSAboththetraditionalNEC500ClassandDivisionclassification,whichisacceptableforinstallationonmostNorthAmericansites,andthemorerecentNEC505Zoneclassification are included. US NEC505 intrinsic safeequipment is codedAEx and the approval is similar tointernationalIECExandEuropeanATEXcertifications.

CanadiancertificationalsoincludesbothDivisionandZoneclassifications. TheCanadianElectricalCodemandatesthatnewinstallationsuseZones,butClassandDivisionsarefrequentlyemployed.

3

http://www.beka.co.uk/datasheets.html

4

FieldGRP

141 x 212mm

Enclosurematerial & size

Model BA304E BA324E

Shown with optionalbacklight

Protection

Separate terminal compartment Yes

Number of digits 4 5and 31

segmentbargraph

Height of digits 34mm 29mm

Certification International & EuropeEx ia IIC T5 Ga Ta -40°C to +70°CIECEx gas

Options must be specified when indicator is ordered

BacklightAlarmsExternal keypad

Certification IECEx & ATEX dust US and Canadian

Ex ia IIIC T80°C Da IP66 Ta -40°C to +70°C dust

II 1G, Ex ia IIC T5 Ga Ta -40°C to +70°CATEX gas

II 1D, Ex ia IIIC T80°C Da IP66 Ta -40°C to +70°C dust

Addition certificationfeatures

Additional certificationfeatures

YesYes

Yes

YesYes

YesYes

Yes

YesYes

Table 1 BA300E & G intrinsically safe indicators

BA304G

No

4

34mm

IP66

YesStandard

Yes

StandardStandard

FieldGRP

122 x 120mm

BA324G

5and 31

segmentbargraph

29mm

Certification USA & Canada Class I Division 1 Groups A, B, C & D T5Class II Division 1 Groups E, G & G T5Class III T5Class I Zone 0 AEx ia IIC T5-40ºC Ta +70ºC

Class I, Div 1, Gp A, B, C & D T5Class I, Zone 0, AEx ia IIC T5 Ga (USA only)-40ºC =Ta = 70ºC

Class II, Div 1, Gp E, F & G. Class III, Div 1Zone 20 AEx ia IIIC T80ºC Da (USA only)-40ºC Ta 60ºC

Ex ia T5 Ga -40ºC Ta 70ºC Ex ia IIIC Da -40ºC Ta 60ºC

(Canada only)

YesStandard

Yes

StandardStandard

5

Certification permits installation inAEx e, AEx p or AEx t panelenclosure without invalidating

enclosure’s certification.

Ex ia IIC T5 Ga Ta -40°C to +70°C

Ex ia IIIC T80°C Da IP20 Ta -40°C to +70°C

II 1G, Ex ia IIC T5 Ga Ta -40°C to +70°C

II 1D, Ex ia IIIC T80°C Da IP20 Ta -40°C to +70°C

Certification permits installation inEx e, Ex p or Ex t panel enclosure

located in Zones 1, 2, 21 or 22without invalidating the panel

enclosure’s certification.

PanelStainless steel 316

105 x 60mm

BA307E-SS BA327E-SS

Front impact resistant & IP66rear IP20

No

4 5and 31

segmentbargraph

15mm 11mm

YesStandard

Yes

StandardStandard

YesStandard

Yes

StandardStandard

PanelPPO (Noryl)96 x 48mm


BA327E BA328E

No

5and 31

segmentbargraph

5and 31

segmentbargraph

11mm 29mm

YesStandard

Yes

StandardStandard

YesStandard

Yes

StandardStandard


BA307E

Front IP66 rear IP20

4 4

15mm

YesStandard

Yes

StandardStandard

Class I Division 1 Groups A, B, C & D T5Class I Zone 0 AEx ia IIC T5

-40ºC Ta +70ºC

BA308E


34mm

YesStandard

Yes

StandardStandard

4. DESCRIPTION OF ATEX & IECEX GAS CERTIFICATION.AlloftheBA300E&GseriesindicatorsandaccessorieshaveATEXandIECExcertification.Thissectiondescribescertificationforinstallationinagashazardousarea,section5describesdustcertification.

4.1 CertificationlabelAllBA300E&GseriesindicatorsarefittedwithanexternallabelshowingtheATEXandIECExcertificationinformationand numbers. The gas certification information on aBA304EcertificationlabelishighlightedinFig2.

BA304E 4 Digit Indicator

associatesYear of manufacture shown within terminal compartment

0359

Hitchin England www.beka.co.uk

ITS11ATEX27253X IECEx ITS11.0014X

II 1 G, Ex ia IIC T5 Ga, -40°C Ta +70°C

Intrinsically safe suitable for Zone 0, 1 or 2Type of explosive atmosphere Gas

CategoryEquipment group

Explosion protection markNotified body identification (Intertek Testing & Certification)

CE Conformity mark

Gas groupTemperature class

Equipment Protection LevelCertification temperature range

Fig2BA304Egascertificationlabel

4.2 Zones, gas groups and T ratingAlloftheBA300Eseriesindicatorshavethefollowinggascode:

IECEx Ex ia IIC T5 Ga Ta-40ºCto70ºC ATEX Group II Category 1G, Ex ia IIC T5 Ga Ta-40ºCto70ºC

Whenconnectedtoasuitablesystemtheindicatormaybeinstalled in:

Zone0 explosivegasairmixturecontinuously present.

Zone1 explosivegasairmixturelikelytooccur in normal operation.

Zone 2 explosivegasairmixturenotlikelytooccur, and if it does will onlyexistforashorttime.

Beusedwithgasesingroups:

Group A propane GroupB ethylene GroupC hydrogen

Ingasesthatmaysafelybeusedwithequipmenthavingatemperatureclassificationof:

T1 450ºC T2 300ºC T3 200ºC T4 135ºC T5 100ºC

Atanambienttemperaturebetween

-40ºCand+70ºC

ThisallowstheBA300E&Gseriesindicatorstobeinstalled inallZonesandtobeusedwithmostcommonindustrialgases at an ambient temperature between -40ºC and+70ºC. Known exceptions (listed in IEC 60079-20-1)beingcarbondisulphideandethylnitratewhichhaveanignitiontemperatureof95ºC.

Note 1: BA300E & G intrinsically safe field mountingindicatorsmay be fittedwith a label containingaluminium and are therefore subject to thefollowingconditionsforsafeuseindicatedbyan‘X’ suffix on the ATEX and IECEx certificationnumbers.

When installed in a Zone 0 potentially explosive atmosphere requiring Equipment Protection Level Ga apparatus, the instrument shall be installed such that even in the event of rare incidents, an ignition source due to impact or friction between the aluminium label and iron/steel is avoided.

These special conditions for field mountingBA300E&GindicatorsarenotrestrictiveasitisveryunlikelythatanindicatorwouldbeinstalledinZone0whereapotentiallyexplosiveatmosphereisalwayspresent.ThisconditiondoesnotapplywhenanindicatorisinstalledinZones1or2.

4.3 4/20mA inputSourcesofenergy thatdonotgeneratemore than1.5V,100mA and 25mW are, for intrinsic safety purposes, considered to be simple apparatus (Clause 5.7 of IEC60079:11).Simple apparatus is easier to incorporate into intrinsicallysafesystemsandrequireslessdocumentationthanothercertifiedintrinsicallysafeapparatus.

Although the BA300E & G series indicators do notthemselves comply with the requirements for simple apparatus, the ATEX and IECEx certificates specifythat under fault conditions the voltage, current andpower output (Uo; Io; Po) from the 4/20mA inputterminals will not exceed those specified for simple apparatus. This allows the output safety parameters ofthe indicator to be ignoredwhen calculating the intrinsicsafety of a loop into which an indicator is inserted.

6

Itisonlynecessarytoestablishthattheoutputparametersoftheloopareequaltoorlessthantheinputparametersof the indicator and that the internal inductance andcapacitanceoftheindicatorareacceptable.

Theoutputparametersoftheloopwhicharedeterminedbytheintrinsicallysafeinterfacepoweringtheloop,beitaZenerbarier,galvanic isolatororassociatedapparatusshouldbeequaltoorlessthan:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

The maximum equivalent capacitance and inductancebetween the two 4/20mA input terminals 1 and 3 of aBA300E indicator are:

BA300E BA300G Ci = 13nF 5.4nF Li = 0.02mH 0.02mH

Todeterminethemaximumpermissiblecableparametersof the loop these figures, plus Ci and Li for any otherinstruments in the loop, should be subtracted from thespecifiedCoandLofortheZenerbarrier,galvanicisolatororassociatedapparatuspoweringtheloop.

Apparatus certificates for intrinsically safe interfacesusually specifyCoandLo for IICgases (hydrogen), thefigures for IIB (ethylene) and IIA (propane) gases areconsiderablylarger.

Itisunlikelythattheadditionalinductanceoftheindicatorwill be restrictive and can usually be ignored, but theadditionalindicatorcapacitancewillreducethemaximumpermissiblecablelength.

4.4 OptionaldisplaybacklightingAll BA300E & G series indicators can be supplied withan optional factory fitted green backlight that has threeterminalsallowingittobelooporseparatelypowered.

When loop powered the backlight produces backgroundillumination allowing the indicator display to be read atnightandinpoorlightingconditions.Looppoweringdoesnot require an additional power supply, intrinsically safeinterfaceorfieldwiring,butthemaximumvoltagedropinthe4/20mAloopcausedbytheindicatorisincreasedfrom1.2 to5.0V. Backlightbrilliance isconstantbetween6and20mAbutslightlydiminishesbelow6mA.

Whenseparatelypoweredthebacklightproducesabrighterbackgroundilluminationwhichenhancesdaylightviewingoftheindicatordisplay,butanadditional intrinsicallysafeinterfaceandfieldwiringarerequired,themaximumvoltagedropoftheindicatorinthe4/20mAloopremainsat1.2V.

4.4.1 Loop poweringTo power the display backlight from the 4/20mA loop,backlight terminals12&13areconnected inserieswiththe 4/20mA indicator input terminals as shown in Fig 6.

Both the ATEX and IECEx certificates confirm thatterminals3&12complywiththerequirementsofsimple apparatuswhenthe indicator’s4/20mAinput terminals1&3areconnected inserieswith thebacklight, terminals12 & 13. The input intrinsic safety parameters of thecombined indicator and loop powered backlight are thesameasthosefortheindicatoralone.Theindicatorandloop powered backlight may therefore be connected inserieswithanycertifiedintrinsicallysafecircuitprovidingtheoutputparametersofthecircuitdonotexceed:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

The maximum equivalent capacitance and inductancebetweeninputterminals3and12are:


Todeterminethemaximumpermissiblecableparametersof the loop these figures, plus Ci and Li for any otherinstrument in the loop, should be subtracted from thespecifiedCoandLofortheZenerbarrier,galvanicisolatororassociatedapparatuspoweringtheloop.

The loop powered backlight increases the maximumvoltagedropoftheBA300E&Gseriesindicatorsto5V.

4.4.2 Separately poweringThebacklightissegregatedfromallothercircuitswithintheindicatorandhasbeencertifiedasaseparateintrinsicallysafecircuit.Itispoweredviaterminals12and14whichmaybeconnected toany intrinsicallysafepowersupplysuchasacertifiedZenerbarrierorgalvanicisolatorhavingoutputparametersequaltoorlessthan:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

TheATEXandIECExcertificatesspecifythatthemaximumequivalent capacitance and inductance between thebacklightterminalsis:


TodeterminethemaximumpermissiblecableparametersthesefiguresshouldbesubtractedfromthespecifiedCoandLofortheZenerbarrierorgalvanicisolatorpoweringthebacklight.

4.5 Optional alarmsAllindicatorscanbesuppliedwithtwofactoryfittedsinglepolesolidstatealarmoutputs.Eachoutputisgalvanicallyisolatedandhasbeencertifiedasaseparateintrinsicallysafe circuit which, complies with the requirements forsimple apparatus.

7

This allowseachalarmoutput to switchany intrinsicallysafecircuitwithoutputparametersnotexceeding:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

TheATEXandIECExcertificatesspecifythatthemaximumequivalent capacitance and inductance between theterminalsofeachalarmoutputis:

BA300E BA300G Ci = 24nF 0 Li = 0.01mH 0.01mH

Todeterminethemaximumpermissiblecableparametersthese figures, plus Ci and Li for other apparatus in thecircuit, should be subtracted from the specified Co andLo of the Zener barrier, galvanic isolator or associatedapparatuspoweringthecircuit.

5. DESCRIPTION OF ATEX & IECEX DUST CERTIFICATIONAllBA300E&GintrinsicallysafeindicatorscanbesuppliedwithATEXandIECExdustcertification.BA300GfieldandtheBA300Epanelmountingmodelshavedustcertificationasstandard,butitmustberequestedforBA300Eseriesfieldmountingmodels.

5.1 CertificationlabelAllBA300E&GseriesindicatorsarefittedwithanexternallabelshowingtheATEXandIECExcertificationinformationand numbers. The dust certification information on aBA304EcertificationlabelishighlightedinFig3.

BA304E 4 Digit Indicator

associatesYear of manufacture shown within terminal compartment

0359

Hitchin England www.beka.co.uk

II 1 G, Ex ia IIC T5 Ga, -40°C Ta +70°C

II 1 D, Ex ia IIIC T80°C Da IP66, -40°C Ta +70°C

ITS11ATEX27253X IECEx ITS11.0014X

Explosion protection mark

Notified body identification (Intertek Testing & Certification)

CE Conformity mark

Equipment group

Category

Type of explosive atmosphere Dust

Intrinsically safe

Dust group

Max surface temperature

Equipment Protection Level

Ingress protection

Certification temp. range

Fig3BA304Edustcertificationlabel

5.2 Zones, dust groups and surface temperatureAlloftheBA300E&Gseriesindicatorshavethefollowingdust code:

Group IICategory1DEx ia IIICT80ºCDa IP66 Ta-40ºCto70ºC

Whenconnectedtoasuitablesystemtheindicatorsmaybeinstalledin:

Zone20 explosiveatmosphereintheform ofacloudofcombustibledustin air is continuously present, or for longperiodsorfrequently.

Zone21 explosiveatmosphereintheform ofacloudofcombustibledustin airislikelytooccuroccasionally in normal operation.

Zone22 explosiveatmosphereintheform ofacloudofcombustibledustin airisnotlikelytooccurinnormal operation,butifitdoesoccur,will onlypersistforashortperiod.

Beusedwithdustinsubdivisions:

IIIA combustibleflyings IIIB non-conductivedust IIIC conductivedust.See note 2

HavingaMinimumIgnitionTemperatureof:

Dustcloud 120°C

Dustlayeronindicator 155°C upto5mmthick

Dustlayeronindicator Referto over5mmthick. IEC60079-14

Atanambienttemperaturebetween-40and+70°C.

Note: BA300E series panel mounting indicators haveIP20rearprotectionandaresubjecttothefollowingspecialconditionsforsafeuseindicatedbyan‘X’suffixontheATEXandIECExcertificationnumbers.

‘When installed in a IIIC conductive dust atmosphere, the indicator shall be mounted such that the instrument terminals have at least IP6X protection.’

ThesespecialconditionsdonotaffectinstallationsinIIIA,IIIBdustorgasatmospheres.

IP6Xindicatesthattherearofthepanelmountingindicatorshouldbetotallyprotectedfromdust,byfor example mounting the indicator in a sealedIP6Xpanelenclosureorcubiclesothatconductivedustcannotaccumulateontheindicatorterminals.For96x48mmandruggedindicators,thiscanbeachievedwithaBA495rearcoversealingkit.

8

6. DESCRIPTION OF NORTH AMERICAN CERTIFICATIONBEKA loop powered indicators have been certifiedintrinsically safe foruse in theUSAandCanadaby twoNationally Recognised Testing Laboratories, FM GlobalandETL.Class/DivisionandZoneapprovalisincludedfor all models.

All installations in the USA should comply with theassociated BEKA Control Drawing. Installation ofintrinsically safe Systems for Hazardous (Classified)Locations ANSI/ISA RP12.6 and the National ElectricalCodeANSI/NFPA70. Any localcodeofPracticeshouldalsobeconsulted.

InstallationsinCanadashouldcomplywiththeassociatedBEKA Control Drawing, The Canadian Electrical CodeC22.1plusanyrelevantlocalcodeofpractice.

6.1 FMcertificationofBA304E&BA324EThe BA304E and the BA324E field mounting indicatorsincorporatingaseparate terminalcompartmenthave thefollowing FM and cFM intrinsic safety codes:

ClassI Division1 GroupsA,B,C&DT5 ClassII Division1 GroupsE,G&GT5 Class III T5 Class I Zone 0 AEx ia IIC T5 -40ºC≤Ta≤+70ºC

Whenconnected toasuitablesystem the BA304EandBA324Efieldmountingindicatorsmaybeinstalledin:

Division1 Explosivegasairmixturelikelyto occur in normal operation

Division2 Explosivegasairmixturenotlikelyto occur and if it does will only exist for a shorttime.


Group A Acetylene Group B Hydrogen GroupC Ethylene GroupD Propane

Ingassesthatmaysafelybeusedwithequipmenthavingatemperatureclassificationof:


Beusedwithdustsingroups:

Group E Metal GroupF Carbonaceous GroupG Non-carbonaceous

Atanambienttemperaturebetween-40ºCand+70ºC

Note: AEx ia IIC T5 Zone coding allows installation in atmospheres similar to those specified for IECEx andATEXcertificationinsection4.

6.2 FMcertificationofBA307E,BA308E,BA327E &BA328EThe BA307E, BA308E, BA327E and the BA328E panelmounting indicators have the following FM and cFMintrinsic safety codes:

ClassI Division1 GroupsA,B,C&DT5 Class I Zone 0 AEx ia IIC T5 -40ºC≤Ta≤+70ºC

When connected to a suitable system these panelmountingindicatorsmaybeinstalledin:








Note: AEx ia IIC T5 Zone coding allows installation in atmospheres similar to those specified for IECEx andATEXcertificationinsection4.

FM & cFM certification of the rugged BA307E-SS &BA327E-SSisdescribedinsection9.4

9

7. HAZARDOUS AREAS APPLICATIONSBA300E and G series ATEX, IECEx, US and Canadian certificationsspecifycommonindicatorsafetyparameters.The circuits shown in this sectionmay be usedwith allindicatorsandwithanyoftheintrinsicsafetycertificationsprovidingthattheinstallationcomplieswiththelocalcodeof practice.

ThetworuggedstainlesssteelpanelmountingindicatorsBA307E-SSandBA327E-SShave thesame IECExandATEX gas and dust certification as the other models.Whilst theymaybeused inanyof theexamplesshownin thissection, theircertificationalsopermits themtobemountedinacertifiedExe,ExporExtpanelenclosurewithout invalidating the panel enclosure’s certificationwhich further extends their applications. The use oftheseruggedinstrumentsincertifiedpanelenclosuresisexplainedinsection9ofthisguide.

7.1 4/20mA loop designA BA300E or G series indicator may be connected inseries with almost any intrinsically safe 4/20mA currentloop and calibrated to display themeasured variable orcontrolsignalinengineeringunits.Therearefourdesignsteps:

1. From table 1 select themodelwith the requireddisplay, mounting and accessories.

4 digit models can display -9999to9999

5 digit models can display -99999to99999withabargraph

2. The output safety parameters of the 4/20mAloop, which are usually defined by the Zenerbarrier,galvanic isolatororassociatedapparatuspoweringtheloop,mustbeequaltoorlessthanthe maximum input safety parameters of theindicator,whichare:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

3. TheequivalentinternalcapacitanceCiandinternalinductanceLioftheindicatorwithorwithoutalooppoweredbacklightis:


WhenaddedtotheCiandLiofotherinstrumentsin the loop, the totals should not exceed thespecifiedCoandLooftheZenerbarrier,galvanicisolator or associated apparatus powering theloop.

4. The loop must be able to supply the additional1.2V required to operate the indicator. If theoptionalbacklight is looppoweredthe loopmustbeabletosupplyanadditional5V.

6.3 ETLandcETLcertificationofBA304G&BA324GTheBA304Gand theBA324G fieldmounting indicatorshavethefollowingETLandcETLintrinsicsafetycode:

ClassI Div1 GpA,B,C,DT5(USA&Canada) Class I Zone 0 AEx ia IIC T5 Ga (USA) -40ºC≤Ta≤70ºC

ClassII Div1 Gp E, F, G Class III, Div 1 (USA & Canada) Zone2 0A ExiaIIICT80ºCDa(USA) -40ºC≤Ta≤60ºC

ExiaT5Ga -40ºC≤Ta≤70ºC ExiaIIICDa -40ºC≤Ta≤60ºC

(Canada)

Whenconnected toasuitablesystemthe BA304GandBA324Gfieldmountingindicatorsmaybeinstalledin:








Be used in dusts in groups:

Group E Metal GroupF Carbonaceous GroupG Non-carbonaceous


Note:AExiaIICT5GaandAExiaIIICT80CZonecodingsallowinstallationinatmospheressimilartothosespecifiedforIECExandATEXcertificationinsections4and5.

10

P E

TAG NUMBER SCALE

2-wireTx

4/20mA4/20mA

3 4 2 16 5

28V; 93mAgalvanic isolator

4/20mA

PowerSupply

+

0

Safe AreaHazardous Area

BA300E or G indicator

Fig4BTransmitterlooppoweredviagalvanicisolator

7.2 Remote indicationBA300E&Gseries indicatorsmayalsobedrivenviaanintrinsically safe interface from a 4/20mA safe area signal to providearemoteindicationwithinahazardousarea.Thetypeof interface isnot critical, aZenerbarrier, galvanicisolatororassociatedapparatusmaybeused,butagainoutput parameters of the interface must not exceed theindicator’smaximuminputparameters.Zenerbarriersaretheleastexpensiveinterfaceparticularlyifahighintegrityearthisalreadyavailable.Ifonesideofthe4/20mAcurrentloop may be earthed, a single channel Zener barrierprovidesthelowestcostprotection.Ifthe4/20mAsignalisnotisolated,twoZenerbarriers,atwochannelZenerbarrieroragalvanicisolatormustbeused.Againitisnecessarytoensurethatthevoltagecapabilityofthe4/20mAsignalis sufficient to drive the indicator plus the voltage dropintroducedby the intrinsicallysafe interface.Fig5showsthethreealternativecircuitswhichmaybeused.

7.3 DisplaybacklightAll BA300E & G series indicators can be supplied withanoptional factoryfitteddisplaybacklight thathas threeterminalsallowingittobelooporseparatelypowered.

7.3.1LooppoweringthebacklightWhen loop powered the backlight produces greenbackground illumination enabling the indicator displaytobereadatnightandinpoorlightingconditions.Looppowering does not require an additional power supply,intrinsicallysafeinterfaceorfieldwiring,butthemaximumindicatorvoltagedropinthe4/20mAloopisincreasedfrom1.2to5.0V.Backlightbrillianceisconstantbetween6and20mAbutslightlydiminishesbelow6mA.

ABA300EorGseriesindicatormaybeconnectedinserieswith a 2-wire intrinsically safe transmitter to display thecurrentandhencetheprocessvariableinengineeringunits.Fig4Aillustratestheuseofa2-channelZenerbarrier,ortwoseparatebarriersastheintrinsicallysafeinterface.Zenerbarriersareusually lessexpensivethangalvanic isolatorsbutdonotprovideisolationandrequireahighintegrityearthwhichifnotavailablemaybeexpensivetoinstall.

P E

TAG NUMBER SCALE

2-wireTx

2 channel Zener barrier28V; 93mA; 300Ωdiode return

4/20mA

4/20mA

4/20mA Load250Ω

3 4 2 1

Instrumentpowersupply

+

0

6 5



Fig4ATransmitterlooppoweredviaZenerbarriers

ConsideringthevoltagedroparoundtheloopinFig4A.

2-wiretransmitter 8.0

Maximumvoltagedropcaused 1.2 byBA300EorGseriesindicator.

Maxvoltagedropcausedby 6.8 28V93mAbarrier. (340Ωend-to-endresistancex20mA)

Maxvoltagedropcausedby 1.4 diodereturnbarrier (21Ωx20mA+0.9V)

Maxvoltagedropcausedby 5.0 250Ωload.(250Ωx20mA)

Maxvoltagedropcausedby 0.2 cables.(10Ωx20mA) ______ Totalvoltagedroparoundloop 22.6V

The instrument power supply must therefore have anoutputabove22.6Vbutbelow25.5Vwhichisthemaximumworkingvoltageofthe28V93mAZenerbarrier.

Fig4Billustratesthesameloopusingagalvanicisolatorastheintrinsicallysafeinterface.Galvanicisolatorsalthoughmoreexpensive thanZenerbarriersallowanon-floatingpowersupply tobeused,donot requireahigh integrityearth connection and in general are easier to apply. Itis usually only necessary to read the manufacturersspecification todetermine thevoltageavailable topowerthehazardousarealoop.

11

Theindicatorsbacklightterminals12(+)and13(-)shouldbeconnected inserieswith the indicator’s4/20mA inputterminalsasshowninFig6.

Anyofthecircuitsshowninsections7.1and7.2maybeusedprovidingthat5Visavailabletopowertheindicatorandthebacklight.


Instrumentwith non-isolated4/20mAoutput

Two channelZener barrier

4/20mA

3 1

4/20mA

Instrumentwith

isolated4/20mAoutput

Single channelZener barrier

4/20mA

3 1

Instrumentwith non-isolated4/20mAoutput

Galvanicisolator

4/20mA

3 1

4/20mA

4/20mA

+

0

+

0

+

0

P E

TAG NUMBER SCALE

P E

TAG NUMBER SCALE

P E

TAG NUMBER SCALE




Fig5Alternativecircuitsforremoteindicationina hazardousareas

P E

TAG NUMBER SCALE

4/20mA

Zener barrier orgalvanic isolator

4/20mA

3 1 13 12

5V

+

0

5V


P E

TAG NUMBER SCALE

2-wireTx

4/20mA4/20mA

3 4 2 1 13 126 528V; 93mAgalvanic isolator

4/20mA

PowerSupply

+

0



Fig6AlternativecircuitsforBA300EorGseriesindicator withlooppoweredbacklight

7.3.2SeparatelypoweringthebacklightSeparatelypoweringthebacklightproducesbrightergreenbackground illumination than looppowering. Itenhancedaylightviewingoftheindicatordisplaybutanadditionalintrinsicallysafeinterfaceandfieldwiringarerequired,themaximumvoltagedropoftheindicatorinthe4/20mAloopremainsat1.2V.

Theseparatelypoweredbacklightisacurrentsinkdrawinga constant current when the supply between terminals12(+)and14(-)isabovetheminimumsupplyvoltage.

Model Current Minimum supply voltage

terminals 12 & 14 BA304E BA304G BA324E BA324GBA308EBA328E

35mA 11V

BA307EBA327EBA307E-SSBA327E-SS

23mA 9V

Table2Separatelypoweredbacklightvoltage&current foreachmodel

12

Belowtheminimumsupplyvoltagethebacklightcontinuestofunctionbutthebrillianceisdiminished.Forapplicationwhere operator’s night vision has to be preserved,adjustingthebacklightsupplyvoltageisasimplemethodofdimmingthedisplaybacklight.

Thebacklight is segregated fromallothercircuitswithintheindicatorandisseparatelypoweredviaterminals12(+)and14(-)whichmaybepoweredfromanyintrinsicallysafeinterfacesuchasacertifiedZenerbarrier,galvanicisolatororassociatedapparatushavingoutputparametersequaltoorlessthan:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

The maximum equivalent capacitance and inductancebetweenthebacklightterminalsis:


To determine the maximum permissible backlight cableparameters these figures should be subtracted from thespecifiedCoandLooftheZenerbarrier,galvanicisolatoror associated apparatus powering the backlight. Fig 7showsanexampleofaZenerbarrierseparatelypoweringthebacklight.

P E

TAG NUMBER SCALE

4/20mAindicatorcircuit

Zener barriers orgalvanic isolators

14 12 3 1

Backlightsupply

+24V

0

+

04/20mA

See table 2for current

1.2VSeetable 2for minvoltage



Fig7BA300EorGseriesindicatorwithseparately poweredbacklight

Two separately powered BA307E or BA327E indicatorbacklights may be connected in parallel to a singlechannel28V,93mAZenerbarrierorgalvanicisolatorwithnonoticeablereductioninbrillianceona24Vdcsupply.

7.4 Optional AlarmsAll BA300E orG series indicators can be suppliedwithtwo factory fitted single pole solid state alarm outputs.Eachoutputisgalvanicallyisolatedandhasbeencertifiedasaseparate intrinsicallysafecircuitcomplyingwith therequirementsforsimple apparatusmakingiteasiertousein intrinsically safe circuits.

Eachoutputmaybe individuallyconfiguredasahighora low alarm with a normally open or a normally closed‘contact’. Fig 8 illustrates the conditions available andshowswhichare‘failsafe’.i.e.outputisinalarmcondition(‘contact’open)whenthe4/20mAinputcurrentiszero.

Normally closed output 'nc'in the non-alarm condition

FAIL SAFE

Normally open output 'no'in the non-alarm condition

NOT FAIL SAFE

4/20mA Input 4/20mA Input

4/20mA Input4/20mA Input

AlarmSetpoint

AlarmSetpoint

AlarmSetpoint

AlarmSetpoint

HIGHALARM

LOWALARM

Outputclosed

Outputclosed

Outputclosed

Outputclosed

OutputOpen

OutputOpen

OutputOpen

OutputOpen

Fig8Alarmoutputs

These alarm outputs are not suitable for use in criticalsafetyapplicationssuchasashutdownsystem.

The equivalent electrical circuit of each alarm output isshown inFig9.Bothoutputsarepolarisedandwillonlypass current in one direction.

(8, 10)

(9, 11)

(8, 10)

(9, 11)

5Ω 0.7V

1M 24nF BA300E 0 BA300G

0.01mH +

==

Fig9Equivalentcircuitofeachalarmoutput

13

8. SPECIAL FUNCTIONSAll BA300E & G series indicators include special functions thatextendtheirapplications.

8.1 Square root extractorAll the BA300E & G series indicators contain a squareroot extractor that allows the output from non-lineariseddifferentialflowtransmitterstobedisplayedinlinearunits.Therootextractorisselectablefromwithintheindicator’sconfigurationmenuusingtheinstrument’spushbuttons.


P E

TAG NUMBER SCALE

levelTx

4/20mA

4/20mAoutput

4/20mA

Horizontal cylindrical tank

3 4 2 14/20mA

supply+0

4 8 12

Input current

Indi

cato

r di

spla

yTa

nk c

onte

nt in

vol

umet

ric u

nits

16 20

161514

13

12

11

10

9

8

7

6

5

43

21


Fig11 Lineariserenablestankcontentstobedisplayed inlinearunitsofvolume

Each alarm output is segregated and is a separateintrinsicallysafecircuit.Itmayswitchanyintrinsicallysafecircuitwithoutputparametersequaltoorlessthan:

Uo ≤ 30Vdc Io ≤ 200mA Po ≤ 0.84W

The maximum equivalent capacitance and inductancebetweentheterminalsofeachalarmoutputis:

BA300E BA300G Ci = 24nF 0 Li = 0.01mH 0.01mH

These figures should be subtracted from the allowablecapacitanceandinductanceofthecircuitbeingswitched.

The alarm outputs may be used to switch intrinsicallysafe loads within the hazardous area or to switch safearea loads via a Zener barrier or a galvanic isolator. Fig10 illustrates how one alarm output of a BA300 seriesindicator canswitchacertified intrinsically safesolenoidvalve locatedinthehazardousareaandtheotheralarmoutput cancontrolapump in thesafeareaviaaswitchtransfergalvanicisolator.

P E

TAG NUMBER SCALE

2-wireTx

4/20mA

Alarm 1

4/20mA

24V supply

4/20mA

3 4 2 14/20mAsupply

8 9 10

+ +

11

Solenoiddriver

Switchtransfer

Alarm 2

CertifiedGalvanic isolators

Pump

+0

0+

0+



Intrinsically safesolenoid valve

Fig 10 Typical alarm application

When an indicator alarm output is used to activate anannunciatorsuchasaflashingbeaconorasounderoneoftheindicatorpushbuttonsmaybeconfiguredtooperateasanalarm‘accept’button.Thisallowstheoperatortosilencethealarmforaconfigurabletimeupto3,600secondsin1secondincrements.Ifthealarmconditionisnotcorrectedduringthesilencetime,thealarmwillbereactivated.

14

8.2 LineariserTheintegrallineariserenablesBA300E&Gseriesindicatorstodisplaynon-linearvariablesinlinearengineeringunits.The function provides a sixteen point fully adjustablestraight line lineariserwhichmay be conditioned on-sitetocompensate formostnon-linearities.Fig11showsanexample inwhich aBA300 series indicator displays thecontentsofahorizontalcylindricaltankinlinearvolumetricunits fromthe4/20mAoutputofa level transmitter. Theinternal lineariser being used to convert the level signalintoavolume.

Thelinearisercanbeadjustedon-siteviatheinstrumentspush buttons, or if the curve parameters are specifiedwhentheindicatorisordered,itcanbesuppliedcalibrated.

8.3 TarePrimarilyintendedforusewithweighingsystems,thetarefunctionreplacesthepercentagefunctionontheindicator.Whenthetarepushbuttonisoperatedformorethanthreeseconds the indicatordisplay isset tozeroand the tareannunciatoractivated,thussubtractingthecurrentdisplayfrom subsequent displays. When used with a weighingsystem, this function subtracts the displayed weight ofanemptycontainerfromtheweightofthecontainerpluscontents,sothatthenetweightofthecontentsisdisplayed.Subsequentoperationofthetarepushbuttonforlessthan3secondswillreturntheindicatortothegrossdisplayanddeactivatethetareannunciator.

9. RUGGED PANEL INDICATOR APPLICATIONSThe two ruggedstainlesssteelpanelmounting indicatorsBA307E-SS and BA327E-SS have the same IECEx andATEXcertificationasalltheothermodelsandmaybeusedinanyoftheapplicationsshowninsection7ofthisguide.In addition, they may be installed into a certified Ex e,Ex p or Ex t panel enclosure located in Zone 1, 2, 21 or 22 withoutinvalidatingthepanelenclosure’scertification,whichenablesthemtodisplayprocessvariablesinhazardousareaequipmentwhichisnotpredominatelyprotectedbyintrinsicsafetysuchascompressorsandpumps.Wheninstalledinacertifiedpanelenclosure,suchasanExecubicle,theruggedindicatorsremainintrinsicallysafeandmayonlybeconnected to an appropriate intrinsically safe circuit.

Bothinstrumentsarehousedinaruggedcaststainlesssteelcasewitha10mmthicktoughenedglasswindow,thejointbetween the instrument case and the panel enclosure inwhichitismountedissealedwithacaptivesiliconegasket.After high and low temperature endurance and impacttesting at below the minimum and above the maximumservice temperature, Notified Body Intertek Testing &Certificationconfirmed that the frontof thecaseprovidesIP66ingressprotectionandcomplieswithExe,ExpandEx t impact and ingress requirements. The ATEX andIECEx intrinsic safety certificates for these two indicatorsthereforecontainspecial conditionspermitting installationinExe,ExpandExtcertifiedpanelenclosures.

9.1 Installation in an Ex e panel enclosure located in Zone 1 or Zone 2InstallationofaBA307E-SSorBA327E-SSindicatorinanEx e IICGb increased safety panel enclosure does notinvalidate theExepanel’scertification,but the indicatorremains Group II Category 1G Ex ia IIC T5 Ga intrinsically safeapparatussoitmustbepoweredviaaZenerbarrierorgalvanicisolatorasdescribedinsection7ofthisguide.

TheZenerbarrierorgalvanic isolator isusually installedinthesafeareabutsomeintrinsicallysafeinterfacesarecertifiedformountingwithinaprotectiveenclosurelocatedinZone2whichmaypermit them tobemounted in thesameExeenclosureas theBA307E-SSorBA327E-SSindicator.WheretheZenerbarrierofgalvanicisolatormaybe located isdefinedby itsATEXEC-TypeExaminationcertificate or IECEx Certificate of Conformity. Zenerbarriersandgalvanic isolatorsarenotpermitted inExeenclosures located in Zone 1.

Bothindicatorshaveanearthstudadjacenttotheterminalsontherearpanel.Forpersonnelsafetyandpreventionofanelectrostaticcharge,thisshouldbeelectricallyconnectedtothepanelenclosureinwhichtheindicatorismounted,ortoalocalbondingpointifthepanelenclosureisnon-conductive.Theindicatorterminals,thewiringtotheindicatorandtheintrinsicallysafeinterface,ifmountedwithintheenclosure,should be segregated fromall other non-intrinsically safewiringandequipmentwithinthepanelenclosure.RequiredsegregationdistancesaredefinedinstandardsEN60079-11Equipment protected by intrinsic safetyandEN60079-14Electrical installations design, selection and erection. Terminalsforintrinsicallysafecircuitsshouldbesegregatedbyat least50mm from terminals fornon-intrinsically safecircuitsandfrombareelectricalconductors.

15

The intrinsically safe terminals and wiring should beidentified and if live maintenance is to be performedanybare livenon-intrinsicallysafepartswithin thepanelenclosureshouldbecoveredandlabelled‘Non-intrinsically safe circuit’topreventaccidentalcontact.

Fig12showsaBA307E-SSorBA327E-SSruggedindicatorinstalled in an Ex e panel enclosure located in Zone 1 or 2. The4/20mAcableshouldbesealedwithanExecertifiedglandwhere it enters theExe panel enclosureand thecablescreenshouldbeearthedtoacommonpointinthesafeareasuchas theplant’sequipotentialconductor,orto theZenerbarrierbusbarwhenbarriersareused. TopreventfaultcurrentsfromotherequipmentinstalledintheEx e enclosure flowing to earth via this cable screen, itshouldbeinsulatedinthehazardousareaandshouldnotbeconnectedtotheExeenclosure.

The power dissipation within an indicator fitted withoperational alarms and a backlight which is separatelypowered is normally about 350mW, in the very unlikelyeventthatall fourcircuitsfail totheworstcaseconditionatthesametime,thetotalpowerdissipationrisesto3.4Wwhich could raise the internal temperature of a smallthermallywellinsulatedpanelenclosure.

Zenerbarrier

4/20mA

Ex e cableglands

BA307E-SS or

BA327E-SSindicator

+4/20mAindicatorcircuit

Zone 1 or 2 hazardous area

Safe area

Ex e panel

enclosure

BA3X7E-SS

Fig 12 Typical installation in an Ex e panel enclosure

9.2 Installation in an Ex p panel enclosure located in Zone 1 or Zone 2Installation of a BA307E-SS or BA327E-SS ruggedindicatorinanExpIICGborExpIICGcpanelenclosuredoesnotinvalidatetheExppanelenclosure’singressorimpact protection as the front of both indicators complywiththeExpingressandimpactrequirements.Becausethe indicator’s front panel push buttons are outside ofthe pressurised panel enclosure, the indicators remainGroup II Category 1G Ex ia IIC T5 Ga intrinsically safe apparatusandmayonlybeconnectedtoanappropriateintrinsicallysafecircuit,evenwhenmountedinanExpxorExpzpanelenclosurewhichcreatesasafeareawithinthepanelenclosure.

Bothindicatorshavefourrearpanelventstoensurethatapotentiallyexplosivegasisnottrappedwithintheinstrumentcase, when installed in an Ex p panel enclosure thesevents,whichareshowninFig13,shouldnotbeobstructed.

Do not obstruct 4 rear vents wheninstalled in an Ex p enclosure

Fig13PositionofventsinBA307E-SS&BA327E-SS

Bothindicatorshaveanearthstudadjacenttotheterminalsontherearpanel.Forpersonnelsafetyandpreventionofanelectrostaticchargethisshouldbeelectricallyconnectedto thepanelenclosure inwhich the indicator ismounted,or to a local bondingpoint if thepanel enclosure is non-conductive. The indicator terminals, the wiring to theindicator and the intrinsically safe interface, if mountedwithin theenclosure,shouldbesegregated fromallothernon-intrinsically safe wiring and equipment within thepanel enclosure. Required segregation distances aredefined in standards EN 60079-11 Equipment protected by intrinsic safetyandEN60079-14Electrical installations design, selection and erection. Terminals for intrinsically safecircuitsshouldbesegregatedbyatleast50mmfromterminals for non-intrinsically safe circuits and from bareelectrical conductors.

Safe areaZone 1 or 2 hazardous area

4/20mA3 1

BA307E-SS orBA327E-SS indicator

Protectivegas inlet

Ex p panelenclosure

Gland maintainsenclosure integrity

2 channel Zener barrier28V; 93mA; 300Ωdiode return

Load

Instrumentpowersupply

+

0

Scalecard

BA3X7E-SS

P E

Fig 14 Typical installation in Ex p panel enclosure

16

Rugged BA307E-SS and BA327E-SS indicators may beinstalled in all three types of pressurised panel enclosure,Expx,ExpyandExpzasshown inFig14. The4/20mAcableshouldbesealedbyaglandwhichmaintainsenclosureintegrity where it enters the Ex p enclosure and the cablescreenshouldbeearthedinthesafeareatoacommonpointsuchas theplantsequipotential conductor,or to theZenerbarrierbusbarwhenbarriersareused.

TopreventfaultcurrentsfromotherequipmentinstalledwithintheExpenclosureflowingtoearthvia thiscablescreen, itshouldbeinsulatedinthehazardousareaandshouldnotbeconnectedtotheExpenclosure.

9.2.1 Ex px panel enclosureWhenpressurisedanExpxenclosurereducestheequipmentprotectionlevel(EPL)insidetheenclosurefromGb(Zone1)tonon-hazardous.WhentheExpxpanelenclosureislocatedinZone1theBA307E-SSandBA327E-SSindicatorsinstalledintheenclosuremayonlybeconnectedtoanExiaorExibintrinsicallysafecircuitwhichwilloftenhave it’s intrinsicallysafe interface located in the safe area. Alternatively, acertified intrinsically safe interface suchasaZenerbarrier,galvanic isolator or associatedapparatusmaybemountedwithintheExpxenclosurewiththeindicator,buttheinterfacemust have vents to ensure that it is fully purgedwhen theenclosure is pressurised. Where the certified intrinsicallysafe interface may be installed is defined by it’s EC-TypeExaminationCertificateorIECExCertificateofConformity.

9.2.2 Ex pz panel enclosureWhenpressurisedanExpzenclosurereducestheequipmentprotection level (EPL) inside the enclosure fromGc (Zone2) to non-hazardous. When the Ex pz panel enclosure islocatedinZone2theBA307E-SSandBA327E-SSindicatorsinstalled in theenclosuremayonlybeconnected toanExia, Ex ib or Ex ic intrinsically safe circuit which will oftenhaveit’s intrinsicallysafe interface located inthesafearea.Alternatively,acertifiedintrinsicallysafeinterfacesuchasaZenerbarrier,galvanicisolatororassociatedapparatusmaybemountedwithintheExpzenclosurewiththeindicator,buttheinterfacemusthaveventstoensurethatitisfullypurgedwhen the enclosure is pressurised. Where the certifiedintrinsicallysafe interfacemaybeinstalled isdefinedby it’sEC-Type Examination Certificate or IECEx Certificate ofConformity.

9.2.3 Ex py panel enclosureWhenpressurisedanExpyenclosurereducestheequipmentprotectionlevel(EPL)insidetheenclosurefromGb(Zone1)toGc(Zone2).WhentheExpypanelenclosureislocatedinZone1theBA307E-SSandBA327E-SSindicatorsinstalledintheenclosuremayonlybeconnectedtoanExiaorExibintrinsicallysafecircuitwhichwilloftenhave it’s intrinsicallysafeinterfacelocatedinthesafearea.Alternatively,acertifiedintrinsicallysafe interfacesuchasaZenerbarrier,galvanicisolatororassociatedapparatusmaybemountedwithintheExpyenclosurebuttheinterfacemustbecertifiedforuseinZone2andhaveventstoensurethatitisfullypurgedwhentheenclosureispressurised.Wherethecertifiedintrinsicallysafe interface may be installed is defined by it’s EC-TypeExaminationCertificateorIECExCertificateofConformity.

9.3 Installation in an Ex t panel enclosure within Zone 21 or Zone 22InstallationofaBA307E-SSorBA327E-SSindicatorinacertifiedExt(dustignitionprotectionbyenclosure)panelenclosuredoesnotinvalidatetheExtpanel’simpactandingressprotectionasthefrontofbothindicatorscomplywithExtimpactandingressrequirements.However,becausetheindicator’sfrontpanelpushbuttonsareoutsideoftheenclosuretheBA307E-SSorBA327E-SSremainGroupIICategory1DExiaIIICT80ºDaintrinsicallysafeapparatusanditmayonlybeconnectedtoanappropriateintrinsicallysafecircuit,ExiaoribforZone21installationsandExia,iboricforZone22installations.Anyofthecircuitsshownin section 7 of thisApplication Guidemay be used butintrinsically safe dust systemsonly need to complywithIIB requirements. Apparatus certificates for intrinsicallysafe interfaces usually specify Co and Lo for IIC gases, butforusewithapparatusindustatmospheresthesemaybeincreasedtotheIIBfigures.ForaIICinterfacewithaUoof28VandanIoof93mA,Coincreasesfrom83nFto650nFandLoincreasesbyafactorof2.25forIIB.

TheZenerbarrier,galvanicisolatororassociatedapparatusisusually installed in thesafearea,but the insideofanExtenclosureiseffectivelyasafeareaandthecertifiedintrinsicallysafeinterfacemaythereforebemountedinthesameExtpanelenclosureastheindicator.

The4/20mAcableshouldbesealedbyaglandwhere itenters the Ex t enclosure and the cable screen shouldbeearthed in thesafearea toacommonpoint suchastheplantsequipotentialconductor,ortotheZenerbarrierbusbarwhenbarriersareused.Topreventfaultcurrentsfromotherequipment installedwithin theEx tenclosureflowing to earth via this cable screen the screen shouldbe insulated in the hazardous area and should not beconnectedtotheExtenclosure.

Bothindicatorshaveanearthstudadjacenttotheterminalson the rearpanel. Forpersonnel safetyandpreventionof an electrostatic charge this should be electricallyconnectedtothepanelenclosureinwhichtheindicatorismounted,ortoalocalbondingpointifthepanelenclosureisnon-conductive.

Theindicatorterminals,thewiringtotheindicatorandtheintrinsicallysafeinterface,ifmountedwithintheenclosure,should be segregated from all other non-intrinsicallysafe wiring and equipment within the panel enclosure.RequiredsegregationdistancesaredefinedinstandardsEN60079-11Equipment protected by intrinsic safety and EN 60079-14 Electrical installations design, selection and erection. Terminals for intrinsically safe circuits should be segregated by at least 50mm from terminalsfor non-intrinsically safe circuits and frombareelectricalconductors.

The intrinsically safe terminals and wiring should beidentified and if live maintenance is to be performedanybare livenon-intrinsicallysafepartswithin thepanelenclosureshouldbecoveredandlabelled‘Non-intrinsically safe circuit’topreventaccidentalcontact.

17

The power dissipation within an indicator fitted withoperational alarms and a backlight which is separatelypowered is normally about 350mW, in the very unlikelyeventthatallfourcircuitsfailtotheworstcaseconditionatthesametime,thetotalpowerdissipationrisesto3.4Wwhich could raise the internal temperature of a smallthermallywellinsulatedpanelenclosure.

9.4 Installation in USA and CanadaTheBA307E-SSandBA327E-SSruggedindicatorshavethe following FM and cFM intrinsic safety certificationpermitting installation inbothDivisionsandZones in theUSA and Canada.

ClassI Division1 GroupsA,B,C&DT5 Class I Zone 0 AEx ia IIC T5 -40ºC≤Ta≤+70ºC

Whenconnectedtoasuitablesystemtheseruggedpanelmountingindicatorsmaybeinstalledin:

Division1 Explosivegasairmixturelikelyto occur in normal operation.

Division2 Explosivegasairmixturenotlikelyto occur, and if it does will only exist for a shorttime.

Beusedwithgasesingroups: Group A Acetylene Group B Hydrogen GroupC Ethylene GroupD Propane

Ingasesthatmaysafelybeusedwithequipmenthavingatemperatureclassificationof: T1 450°C T2 300°C T3 200°C T4 135°C T5 100°C

Atanambienttemperaturebetween-40°Cand+70°C.

For installations of these rugged indicators in the USAand Canada the intrinsically safe circuits shown in thisApplication Guide may be used providing the Zenerbarriers and galvanic isolators have local approval andthe installationcomplieswith theBEKAControlDrawingCI300-72. Acopyof thisControlDrawing is included intheBA307E-SSandBA327E-SSinstructionmanualwhichmaybedownloadedfromtheBEKAwebsite.

Section 14 of the FM and cFM intrinsic safety ControlDrawingCI300-72statesthatwhencorrectlyinstalledinanAExe,AExn,AExporAExtpanelenclosure,theruggedBA307E-SSandBA327E-SSindicatorswillnotinvalidatetheenclosurecertification.InstallationrecommendationsfortheseruggedindicatorsinExe,ExpandExtenclosuresdescribed insections9.1,9.2and9.3of thisguidemaythereforealsobeused forsimilar installations in theUSandCanadian, but the installationmust complywith thelocal code of practice.

Note:CertifiedAExe,AExn,AExpandAExtenclosuresmayonly be installed in areaswith zoned classification,notinareaswithdivisionclassification.

10. LOOP POWERED 4/20mA RATE TOTALISERSIn addition to this range of ‘E’ loop powered indicators,complementary loop powered intrinsically safe rate totalisers are also available. These instruments displaythe4/20mAoutputfromaflowtransmitterinlinearunitsofflow,andsimultaneouslyshowthetotalflowonaseparatedisplay.

BEKAassociatesLtd. OldCharltonRoad.,Hitchin,Herts.SG52DAUKTel:(01462)438301Fax:(01462)[email protected] www.beka.co.uk

18

mailto:sales%40beka.co.uk?subject=

http://www.beka.co.uk

Modifications

Issue10 30thSeptember2014-SSmodels added

Issue11 18thMarch2015-FmandcFMaddfor SSmodels.CRN1515

Issue12 3rdDecember2015-Updatedtoinclude Gindicators.CRN1560

Issue13 14thNovember2017-ETLcertinfo addedanderrorscorrected.P0178

Issue14 15thFebruary-CRN1727INMETRO certificationremoved.

Documents

Application Guide AG300 Issue 14 - BEKA · Application Guide AG300 Issue 14 BA300E & G Series intrinsically safe 4/20mA loop powered indicators