GDS GASMAX CX User manual

GDS Corp.
1245 Butler Road League City, TX 77573
409-927-2980 409-927-4180 (Fax) ww.gdscorp.com
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Operation and Maintenance
Manual
GASMAX CX Single / Dual Channel Gas Monitor

GASMAX CX Operation & Maintenance Manual, Revision 1.0
Page 2
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CAUTION: FOR SAFETY REASONS THIS EQUIPMENT MUST BE OPERATED AND
SERVICED BY QUALIFIED PERSONNEL ONLY. READ AND UNDERSTAND
INSTRUCTION MANUAL COMPLETELY BEFORE OPERATING OR SERVICING.
ATTENTION: POUR DES RAISONS DE SÉCURITÉ, CET ÉQUIPEMENT DOIT
ÊTRE UTILISÉ, ENTRETENU ET RÉPARÉ UNIQUEMENT PAR UN PERSONNEL
QUALIFIÉ. ÉTUDIER LE MANUE D’INSTRUCTIONS EN ENTIER AVANT
D’UTILISER, D’ENTRETENIR OU DE RÉPARER L’ÉQUIPEMENT.
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REVISION HISTORY
Revision 1.0 4/15/14 Initial Release
Copyright © 2014 GDS Corp. All Rights Reserved
P/N 1200-0872-01

GASMAX CX Operation & Maintenance Manual, Revision 1.0
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CONTENTS
1SAFETYINFORMATION_______________________________________________7
2OVERVIEW_________________________________________________________8
3HARDWARE________________________________________________________9
4INSTALLATION_____________________________________________________10
SelectingaLocation__________________________________________________________10
ExplosionProofInstallation___________________________________________________10
IntrinsicallySafeInstallation___________________________________________________10
MountingtheGASMAXCXInstrumentEnclosure__________________________________10
ConnectingDCPower&OutputSignalWiring____________________________________11
ConnectingtoanEthernetNetwork_____________________________________________12
OptionalRelay/MODBUSInterface____________________________________________12
OptionalMODBUSJunctionBox
________________________________________________13
LocalSmartToxicsensor______________________________________________________15
ConnectingaRemoteToxicSensortransmitter___________________________________16
LocalSmartBridgeSensor_____________________________________________________17
ConnectingaRemoteINFRAREDSensortransmitter_______________________________18
LocalGDS‐IRInfraredSensor__________________________________________________19
ConnectingaRemoteGDS‐IRInfraredSensor_____________________________________20
ConnectinganExternal4‐20mAInputDevice_____________________________________21
5SETUPANDOPERATION_____________________________________________22
GASMAXControlsandDIsplay_________________________________________________22
DisplayScreens_____________________________________________________________23
InitialSetup________________________________________________________________24

GASMAX CX Operation & Maintenance Manual, Revision 1.0
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NormalOperatingMode______________________________________________________24
AlarmOperation–ALARM1,2and3___________________________________________24
AlarmOperation–FAULT_____________________________________________________25
6CALIBRATION______________________________________________________26
CalibrationOverview_________________________________________________________26
CalibrationProcedure________________________________________________________27
7MAINTENANCE_____________________________________________________29
NormalMaintenance________________________________________________________29
SensorReplacement–LocalSensors____________________________________________29
SensorReplacement–RemoteSensors__________________________________________30
8TROUBLESHOOTING_________________________________________________32
ToxicSensorIndicatesFaultorOverrange________________________________________32
ToxicSensorWillNotCalibrate________________________________________________32
BridgeSensorIndicatesFaultorOverrange_______________________________________32
BridgeSensorWillNotCalibrate_______________________________________________32
ReceivingDeviceandGASMAXDisplayedValuesDon’tMatch_______________________33
ControllerMODBUSDataIncorrect_____________________________________________33
ControllerShowingMODBUSCOMMERROR_____________________________________33
GASMAXDisplayBlank_______________________________________________________33
Softwarereset(“ColdBoot”)__________________________________________________33
9SPECIFICATIONS____________________________________________________34
10USERMENUS____________________________________________________35
AlarmOutputsMenu________________________________________________________36
ChannelSettingsMenu_______________________________________________________37

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CommSettingsMenu________________________________________________________39
SystemSettingsMenu________________________________________________________40
DiagnosticsMenu___________________________________________________________41
11NETWORKINTERFACE_____________________________________________42
MODBUSRegisters__________________________________________________________42
12SPAREPARTS____________________________________________________50
SensorHeadAccessories______________________________________________________51
13DRAWINGSANDDIMENSIONS______________________________________52
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GASMAX CX Operation & Maintenance Manual, Revision 1.0
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TABLEOFFIGURES
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FIGURE3‐1GASMAXCXGASMONITOR.........................................................................................................9
FIGURE4‐1:GASMAXCXI/OPOWER&SIGNALWIRING.............................................................................11
FIGURE4‐2ETHERNETINTERFACE...............................................................................................................12
FIGURE4‐3GASMAXCXOPTIONALRELAY/MODBUSINTERFACE..............................................................12
FIGURE4‐4:MODBUSWIRINGJUNCTIONBOX............................................................................................13
FIGURE4‐5:MODBUSJBOXLOCATIONOPTIONS........................................................................................14
FIGURE4‐6:LOCALSMARTTOXICSENSORCONNECTION...........................................................................15
FIGURE4‐7:REMOTETOXICSENSORTRANSMITTERCONNECTION............................................................16
FIGURE4‐8:LOCALSMARTBRIDGESENSORCONNECTION.........................................................................17
FIGURE4‐9REMOTEINFRAREDSENSORTRANSMITTER..............................................................................18
FIGURE4‐10:LOCALGDS‐IRINFRAREDSENSOR..........................................................................................19
FIGURE4‐11:REMOTEGDS‐IRCONNECTION...............................................................................................20
FIGURE4‐12:REMOTE4‐20MAINPUT.........................................................................................................21
FIGURE5‐1:GASMAXCXDISPLAYSCREENSEQUENCE................................................................................22
FIGURE5‐2GASMAXDATADISPLAY............................................................................................................23
FIGURE5‐3GASMAXTRENDDISPLAY..........................................................................................................23
FIGURE6‐1:CALIBRATIONFLOWCHART......................................................................................................28
FIGURE7‐1:GASMAXSENSORREPLACEMENT.............................................................................................30
FIGURE10‐1:MAINMENUTREE..................................................................................................................35
FIGURE10‐2:ALARMOUTPUTSMENUTREE...............................................................................................36
FIGURE10‐3:CHANNELSETTINGSMENUTREE(1)......................................................................................37
FIGURE10‐4:CHANNELSETTINGSMENUTREE(2)......................................................................................38
FIGURE10‐5:COMMSETTINGSMENU........................................................................................................39
FIGURE10‐6:SYSTEMSETTINGSMENUTREE..............................................................................................40
FIGURE10‐7:DIAGNOSTICSMENUTREE.....................................................................................................41
FIGURE12‐1:GASMAXCX+LOCALSENSORSPAREPARTS..........................................................................50
FIGURE12‐2:GASMAXSENSORHEAD.........................................................................................................51
FIGURE12‐4:GASMAXSENSORHEADSPLASHGUARD&FLOWCELL.........................................................51
FIGURE13‐1GASMAXCXDIMENSIONS.......................................................................................................52
FIGURE13‐2GASMAXCXREMOTESENSORTRANSMITTERDIMENSIONS...................................................53

GASMAX CX Operation & Maintenance Manual, Revision 1.0
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1SAFETYINFORMATION
Important–ReadBeforeInstallation
UsersshouldhaveadetailedunderstandingofGASMAXCXoperatingandmaintenanceinstructions.Use
theGASMAXCXonlyasspecifiedinthismanualordetectionofgasesandtheresultingprotection
providedmaybeimpaired.ReadthefollowingWARNINGSpriortouse.
WARNINGS
TheGASMAXCXgasmonitordescribedinthismanualmustbeinstalled,operatedand
maintainedinaccordancewithinformationcontainedherein.Installationinanyhazardousarea
mustcomplywithallapplicablerestrictions,requirementsandguidelinesforsaidhazardous
areas.Itistheendusercustomer’sfinaldecisiontoensurethattheGASMAXCXissuitablefor
theintendeduse.
TheGASMAXCXisdesignedandconstructedtomeasurethelevelofcertaingasesinambientair.
Accuracyinatmospherescontainingsteamorinertgasescannotbeguaranteed.
Alwaysmountthesensorheadverticallywiththesensorheadfacingdown.However,theGDS‐IR
infraredsensormaybemountedverticallyorhorizontally.
Donotpainttransmitterorsensorassembly.
DonotoperatetheGASMAXCXifitsenclosureisdamagedorcrackedorhasmissing
components.Makesurethecover,internalPCB’sandfieldwiringaresecurelyinplacebefore
applyingpower.
DonotexposetheGASMAXCXtoelectricalshockorcontinuousseveremechanicalshock.
ProtecttheGASMAXCXandrelatedsensorassembliesfromdrippingliquidsandhighpower
sprays.
Calibratewithknowntargetgasatstart‐upandcheckonaregularschedule,atleastevery90
days.Morefrequentinspectionsareencouragedtospotproblemssuchasdirt,oil,paint,grease
orotherforeignmaterialsonthesensorhead.
Periodicallytestforcorrectoperationofthesystem’salarmeventsbyexposingthemonitortoa
targetedgasconcentrationabovetheHighAlarmsetpoint.
Useonlyforapplicationsdescribedwithinthismanual.
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GASMAX CX Operation & Maintenance Manual, Revision 1.0
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2OVERVIEW
TheGASMAXCXisasingleordualchannelfixed‐pointgas
monitordesignedtoprovidecontinuousmonitoringoftoxic
orcombustiblegasesinhazardousareas.Gasvaluesare
displayedincalibratedengineeringunitsaswellasbargraph
or30‐minutetrendgraphformat.
TheGASMAXCXsupportsoneortwolocalorremotemount
sensorsfortoxicorcombustiblegases.Theadvanced
microcontroller,non‐intrusivemagneticinterfaceand
superiorfullcolorgraphicLCDinterfaceoffersrapidsetup,
simplifiedoperationandenhanceddiagnosticsnotfoundin
previousgenerationproducts.On‐boardnon‐volatile
memoryretainsallconfigurationdataduringpower
interruptions.Twoindependent4‐20mAoutputsallowfor
easyconnectiontocontrolsystemsorotheralarm
instrumentation,andabuilt‐inEthernetportallowstheGASMAXCXtobeeasilyintegratedintoafacilities
network.Additionaloutputoptionsinclude4xalarmrelaysanddualchannelMODBUSslaveinterfaces.
Built‐inuser‐promptedcalibrationmakesiteasyforonepersontoperformcalibrationandmaintenance
withoutopeningtheenclosureordeclassifyingthearea.Abattery‐poweredreal‐timeclockandeventlog
allowstheGASMAXCXtotrackcalibrationandalarmeventsforlaterrecallontheLCDreadout.
FortoxicgasestheGASMAXCXsupportsawiderangeofelectrochemical(“echem”)sensors.These
sensorsusechemicalreactionstosensethepresenceofgasessuchashydrogensulfide,chlorine,sulfur
dioxideandmanyothers.Unlikepreviousgenerationgasdetectors,GASMAXCXsensorscontainallthe
necessarymicro‐electronicsneededtoconverttheextremelylowlevelsensoroutputsignalsintodigital
valuesthatareimmunetointerferenceandnoise.Whencombinedwithstate‐of‐the‐artdigitalsignal
processingandfiltering,theGASMAXiscapableofgasdetectinglevelslowerthaneverbefore.
ForcombustiblegasestheGASMAXCXoffersthreedifferentchoices.Inadditiontotraditionalcatalytic
bead(“catbead”)sensor,theGASMAXCXsupportstheGDSCorpSmartIRinfraredsensorandGDS‐IR
infraredsensoraswellasthelatestgenerationphotoionizationdetector(PID)sensorsformeasurement
ofvolatileorganiccompoundssuchasbenzeneortoluene.

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3HARDWARE
TheGASMAXCXisenclosedinaCSA/FM/IECExcertifiedanodizedaluminumexplosionproofyellow
enclosuredesignedtoprotecttheelectronicsandmakeiteasyforworkerstoidentifyinindustrial
environments.Thescrew‐onfrontcoveriseasilyremovedforinstallationandmaintenance;however,
built‐inuserinterfacemagneticswitchesallowoperatorsandtechnicianstoadjust,calibrateor
troubleshoottheGASMAXCXwithoutdeclassifyingthearea.
Localsensorsarecontainedinastainlesssteelsensorhead,typicallyattachedtothebottomofthe
GASMAXCXasshownbelow.Thenormalsensorheadincludesanintegratedstainlesssteelflamearrestor
thatmustberemovedforthedetectionofcertainreactivegasessuchaschlorineorchlorinedioxide.If
removed,theGASMAXCXisnotcertifiedforuseinhazardousareas.
SeeChapter13fordrawingsanddimensions.
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
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Figure 3-1 GASMAX CX GAS MONITOR

OptionalSplashGuard
RemovableFrontCover
ColorLCD
Display
SensorHead&GasSensor
¾”NPT
Conduit
Entry(2x)

GASMAX CX Operation & Maintenance Manual, Revision 1.0
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4INSTALLATION
SELECTINGALOCATION
Factorssuchasprevailingwinds,targetgasdensity,potentialleaksources,airmovementmachineryand
similarenvironmentalvariablesareimportantwhenselectingalocationfortheGASMAXCXgasmonitor
orgassensor.EventhoughtheGASMAXCXisdesignedforruggedservice,sensorsandelectronicsshould
beprotectedfromenvironmentaldamageduetowater,snow,shock,vibrationanddirt.Inaddition,the
sensorand/ordisplayshouldbelocatedsuchthatregularmaintenanceandperiodicsensorreplacement
canbereadilyaccomplished.Whiletherearenoindustrystandardsforgasdetectorplacement,
professionaltoolsexistthatcansimulateleaksorspillsandprovideexcellentguidanceforlocatinggas
detectorsthroughoutafacility.
EXPLOSIONPROOFINSTALLATION
GASMAXCXmonitorswithstandardexplosion‐proofsensorheadsarecertifiedforuseinClass1Division
1hazardousareas.Installationintheseareasshouldfollowbestindustrystandardpracticesandall
appropriateelectricalcodes.Generally,thesecodesrequirerigidmetalconduit,pouredsealsandother
installationelementsnecessarytoensuresafety.Inallcases,GDSCorprecommendsanyGASMAXsensor
bemountedverticallywiththesensoropeningfacingdown.Ifthereisapossibilitythatwaterorother
liquidmaybepresent,GDSCorpfurtherrecommendstheinstallationofasensorheadSplashGuard(p/n
10‐0205)toprotectthesensorfromdamage.FormaximumprotectionagainstRFinterferenceor
electricalsurge,theGASMAXCXenclosure,allremotesensorsandinterconnectingconduitmustbe
properlygrounded.
INTRINSICALLYSAFEINSTALLATION
TheGASMAXCXisnotcertifiedforuseasanIntrinsicallySafedevice.
MOUNTINGTHEGASMAXCXINSTRUMENTENCLOSURE
TheGASMAXCXstandardenclosureisacastaluminumexplosion‐proof(NEMA7)enclosureasshownin
Figure4‐1.TwochannelGASMAXCXunitswithduallocalsensorheadsincludea“Y”adapter,shownin
Figure4‐2.
TheGASMAXCXorremotesensorshouldalwaysbemountedwiththesensorheadopeningfacingdown.
Ifnecessary,aSplashGuard(p/n10‐0205)shouldbeattachedifthereisanychancethatwaterorliquid
spraycouldenterthesensoropeningfrombelow.Besuretoleavesufficientroom(~12”)belowthe
sensorheadtoallowforambientaircirculationandeasyaccessforattachmentofaCalibrationCupand/
orremovalofthesensorheadcoverforsensorreplacement.

GASMAX CX Operation & Maintenance Manual, Revision 1.0
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Page 11
CONNECTINGDCPOWER&OUTPUTSIGNALWIRING
ToaccesstheGASMAXsignalandpowerconnections,removethecoverontheGASMAXCXexplosion‐
proofenclosure,loosenthe2thumbscrewsholdingthedisplayassemblyandremoveit.Thedisplaywill
remainconnectedtotheIO/PowerSupplyPCBmountedinthebackoftheenclosurebyashortribbon
cable.Routethepowerandsignalwiresthroughtheconduitentryandconnecttoterminalblock“TB1”.
Plus24VDCconnectstoTB1‐1.DCGroundconnectstoTB1‐4.ChannelOne4‐20mAoutputisavailableon
TB1‐2andChannelTwo4‐20mAoutputisavailableonTB1‐3.GDSCorpalwaysrecommendsusing
shieldedwireforsignalandpowercable.



Figure 4-1: GASMAX CX I/O Power & Signal Wiring


COM
420OUT2 420OUT1
PW
R

R/PW
R

C/420IN1
A/CO
M

420IN2
CH1CH2
E‐NET
LOCAL 
SENSOR
TODISPLAY
TB1
–
1:+12‐30VDCInput
TB1–2:Channel14‐20mAOut
TB1–3:Channel24‐20mAOut
TB1–4:Power/SignalCommon
NOTE:THEMAXIMUMDISTANCE4‐20MASIGNALSCANTRAVELISDEPENDENTUPONCABLE
GAUGE,DCPOWERSUPPLYVOLTAGELEVELANDINPUTIMPEDANCEOFTHERECEIVINGDEVICE.
ASSUMINGANOMINAL24VDCPOWERSUPPLY,100OHMLOADANDMAXIMUMTOTALLOOP
RESISTANCEOF750OHMS:
#18GA,0.0064OHM/FT=>9.6MILES/15.5KM
#24GA,0.026OHMS/FT=>2.3MILES/3.7KM

GASMAX CX Operation & Maintenance Manual, Revision 1.0
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CONNECTINGTOANETHERNETNETWORK
TheGASMAXCXprovidesastandard10/100EthernetnetworkinterfaceonthePowerI/Oboardasshown
inFig.4‐2.BothDHCPandfixedIPaddressmodesareprovided.TheEthernetinterfaceprovidesaccessto
theMODBUSdatabaseviaMODBUS/TCPaswellasremoteaccessandsetupviaabuilt‐inwebserver.


Figure 4-2 Ethernet Interface


OPTIONALRELAY/MODBUSINTERFACE
TheoptionalRelay/Modbusboardisconnected“piggyback”tothebackoftheGASMAXCXDisplay
Assemblyandprovidesthreelevelalarmrelays,aFAULTrelay(“K3”),twoRS‐485ModbusRTUserialports
andaccesstotheDigitalInput/RemoteACKport.


Figure 4-3 GASMAX CX Optional Relay / MODBUS Interface
COM
420OUT2 420OUT1
PW
R

R/PW
R

C/420IN1
A/CO
M

420IN2
CH1CH2
E‐NET
LOCAL
SENSOR
TODISPLAY
2
3
4
1
TB1
5
B
S
A
A
B
TB2
RelayWiring:
1Fault1NC
2Fault1Common
3Fault1NO
4Relay3NC
5Relay3Common
6Relay3NO
7Relay2NC
8Relay2Common
9Relay2NO
10 Relay1NC
11 Relay1Common
12 Rela
y
1NO
MODBUSinterface
ModbusWiring:
1Modbus1A
2Modbus1B
3ShieldTiePoint
4Modbus2A
5Modbus2B
RemoteAlarmAcknowledge
S1
–
Ethernet
RJ‐45Connector
NOTE:USERMENUCHANGESTO
NETWORKSETUPPARAMETERS
REQUIRESADEVICEREBOOT.
NOTE:STANDARDETHERNET
CABLESWITHMOLDEDSTRAIN
RELIEFFITTINGSARENOT
RECOMMENDEDDUETOSPACE
CONSTRAINTS.

GASMAX CX Operation & Maintenance Manual, Revision 1.0

Page 13
+24 GND A 
+24 GND A 
PWRto
MODBUSto
+24
GND
“
A
”
“B”
+2
4
GND
“
A
”
“B”
OPTIONALMODBUSJUNCTIONBOX
MODBUSsystemarchitecturerequiresthatthedevicesinanyMODBUSloopbeconnectedinadaisy‐
chainlayout.Thisminimizessignalreflectionsandimprovessignalnoisemargin.AMODBUSTermination
JumperinstallsaloadresistoracrosstheMODBUSsignallinesandshouldonlybesetto“A”(ON)atthe
lastdeviceinthestring.
CableselectionforMODBUSsystemsisimportantforbothsignalintegrityandpowerdistribution.
MODBUS/RS‐485transmissionsuselow‐voltagedifferentialsignalingtoachievereasonabledatarates
oververylongdistances,upto4000feetwithoutarepeater.
ForMODBUSdatasignals,GDSCorprecommends20GAto
24GAtwistedshieldedcable.Daisy‐chainpowerdistribution
mayrequirelargergaugewiresinceitiscriticalthatthe
supplyvoltagefortheGASMAXCXatthefarendofthestring
notfallbelow12VDCduringpower‐up.






NotethatwhiletheGASMAXCXhastwosetsofwiring
terminalsforMODBUS“A”and“B”signals,daisy‐chainpower
wiringrequiresthattwowiresbeinstalledinthe“+24”and
“GND”terminalsontheGASMAXCXI/OPowerSupplyboard.This
canbedifficultifwiresizesarelargerthan#18GA.Forthesereasons,if
MODBUSisrequiredGDSCorprecommendstheadditionofthe
MODBUSWiringJunctionBox(seeFig.5‐7).Thisoptionminimizesthe
needtoaccesswiringinsidetheGASMAXCX,providesindividualwirelandingpointsforincomingand
outgoingMODBUSandpowerwiringandshields,andmakesiteasytotemporarilydisconnectthe
GASMAXCXpowerorMODBUSconnectionswithoutaffectinganyotherMODBUSdevice.


Figure 4-4: MODBUS Wiring
Junction Box
TOGASMAXCX
ENCLOSURE

GASMAX CX Operation & Maintenance Manual, Revision 1.0
Page 14
TheMODBUSwiringjunctionboxisattachedtotheGASMAXCX,eitheronthebottomfittingoroneof
thesidefittings,dependingoninstallationrequirements.SpecifyBOTTOM,LSIDEorRSIDEwhenordering
(SeeFig.4‐5).




Figure 4-5: MODBUS JBOX LOCATION OPTIONS



“BOTTOM”
“LSIDE”

GASMAX CX Operation & Maintenance Manual, Revision 1.0

Page 15
LOCALSMARTTOXICSENSOR
LocalSmarttoxicsensorsarefactoryinstalledinasensorheaddirectlyattachedtotheGASMAXCX
enclosure.LocalSmarttoxicsensorsandcanbeconnectedtoeitherChannel1orChannel2sensorinputs
ontheI/OPowerSupplyboardasshownbelow.
Smartsensorsareautomaticallyrecognizedonpower‐upanduploadrange,calibrationandproduction
dateinformationtotheGASMAXforuseduringoperationandsetup.




Figure 4-6: Local Smart Toxic Sensor Connection


IMPORTANT:TOXICSENSORSARESUBJECTTOACCELERATEDDETERIORATIONIFPOWERISNOT
SUPPLIEDWITHIN3MONTHSOFSHIPMENTFROMGDSCORP.
COM
420OUT2 420OUT
1

PW
R

R/PW
R

C/420IN
1

A/COM
420IN2
CH1CH2
E‐NET
LOCAL 
SENSOR
TODISPLAY
SmartTOXICsensors
canbeconnectedto
eitherCH1orCH2

GASMAX CX Operation & Maintenance Manual, Revision 1.0
Page 16
CONNECTINGAREMOTETOXICSENSORTRANSMITTER
GASMAXCXmonitorswithremote‐mounttoxicsensortransmittersareshippedintwopiecesandsensor
wiringmustbeinstalledbytheenduser.RemotetoxicsensortransmittersconnecttotheChannel1or
Channel24‐20mAanaloginputconnectionsonthePowerI/Oboardasshownbelow.
Remotetoxicsensortransmittersuseindustrystandard4‐20mAsignallevelsandcanthereforebe
mountedatsomedistancefromtheGASMAXCX.GDSCorprecommendsamaximumdistanceof500ft./
150musingshieldedtwo‐wirecablesizedappropriately.




Figure 4-7: Remote Toxic Sensor Transmitter Connection


NOTE:FIELDWIRINGFORREMOTETOXICSENSORTRANSMITTERSISNOTPOLARIZEDANDMAYBE
CONNECTEDINANYORDER.

IMPORTANT:TOXICSENSORSARESUBJECTTOACCELERATEDDETERIORATIONIFPOWERISNOT
SUPPLIEDWITHIN3MONTHSOFSHIPMENTFROMGDSCORP.
CO
M

420OUT2 420OUT1
PWR
R/PW
R

C/420IN1
A/CO
M

420IN2
CH1CH2
E‐NET
LOCAL
SENSOR
TO DISPLAY
RemoteTOXICsensor
transmitterscanbe
connectedtoeither
CH1orCH2
4‐20mAinput
GASMAXCXGDS‐49REMOTESENSORTRANSMITTER

GASMAX CX Operation & Maintenance Manual, Revision 1.0

Page 17
LOCALSMARTBRIDGESENSOR
Localbridge‐typesensors,includingcatalyticbead,SmartIRinfraredsensorsforcombustiblesandCO2
andphotoionizationdetectors(PID)forvolatileorganiccompoundsarefactoryinstalledandmustbe
connectedtotheCH1SmartSensorconnectorasshownbelow.




Figure 4-8: Local Smart Bridge Sensor Connection


NOTE:LOCALSMARTBRIDGESENSORSAUTOMATICALLYADJUSTSENSOREXCITATIONVOLTAGE.



COM
420OUT2 420OUT
1

PW
R

R/PW
R

C/420IN
1

A/COM
420IN2
CH1CH2
E‐NET
LOCAL 
SENSOR
TODISPLAY
LOCALSMARTBRIDGE‐TYPE
SENSORSMUSTBE
CONNECTEDTOCH1

GASMAX CX Operation & Maintenance Manual, Revision 1.0
Page 18
CONNECTINGAREMOTEINFRAREDSENSORTRANSMITTER
GASMAXCXmonitorswithremote‐mountinfraredsensortransmitterforcombustiblesorCO2are
shippedintwopiecesandsensorwiringmustbeinstalledbytheenduser.Remoteinfraredsensor
transmittersconnecttotheChannel1orChannel24‐20mAanaloginputconnectionsonthePowerI/O
boardasshownbelow.
Remoteinfraredsensortransmittersuseindustrystandard4‐20mAsignallevelsandcanthereforebe
mountedatsomedistancefromtheGASMAXCX.GDSCorprecommendsamaximumdistanceof500ft./
150musingshieldedtwo‐wirecablesizedappropriately.



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Figure 4-9 Remote Infrared Sensor Transmitter


NOTE:FIELDWIRINGFORREMOTEINFRAREDSENSORTRANSMITTERSISPOLARIZEDANDCORRECT
WIRINGPOLARITYMUSTBEOBSERVED.

CO
M

420OUT2
420OUT1
PWR
R/PW
R

C/420IN1
A/COM
420IN2
CH1CH2
E‐NET
LOCAL 
SENSOR
TODISPLAY
PWR mA OUT GND
PW
GASMAXCXGDS‐50 REMOTESENSORTRANSMITTER

GASMAX CX Operation & Maintenance Manual, Revision 1.0

Page 19
LOCALGDS‐IRINFRAREDSENSOR
WhentheGASMAXCXisconfiguredtoincludeaGDS‐IRInfraredCombustibleorCO2sensor,the
IO/PowerSupplyboardisfactorymodifiedtomakeChannel2compatiblewiththesensor’s4‐20mAinput
signal.Anintegrated“zeroset”pushbuttonandmagneticzeroswitchisincludedinsidetheGASMAXCX
enclosureandisusedtoperiodicallysetthezeropointfortheGDS‐IR.



Figure 4-10: Local GDS-IR Infrared Sensor

COM
420OUT2 420OUT1
PWR
R/PWR
C/420IN1
A/COM
420IN2
CH1CH2
E‐NET
LOCA L 
SENSOR
TO DISPLAY
GASMAXCXwithLOCALGDS‐IRSENSOR
GDS‐IRINTERFACEBOARDMOUNTED
INSIDEGASMAXCXENCLOSURE
USEMAGNETICWANDTOACTIVATESET
ZEROSWITCHMOUNTEDONGDS‐IR
INTERFACEBOARDINSIDEGASMAXCX
ENCLOSURE

GASMAX CX Operation & Maintenance Manual, Revision 1.0
Page 20
CONNECTINGAREMOTEGDS‐IRINFRAREDSENSOR
GASMAXCXmonitorswithremote‐mountGDS‐IRsensorsareshippedintwopiecesandsensorwiring
mustbeinstalledbytheenduser.GDS‐IRsensorscanbemountedupto500feetfromtheGASMAX
display.Cableusedshouldbethree‐wirestrandedwithfoilshield.GDSCorprecommendsBeldenB8771.
ThecableshieldmustbeconnectedtoanearthgroundatONEENDONLY.Inthisconfigurationthezero‐
setpushbuttonislocatedintheGDS‐IRremotemountjunctionbox.


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Figure 4-11: Remote GDS-IR Connection
TB1
PWR
A ZE-
TB2
CO
COM
420OUT2 420OUT1
PWR
R/PWR
C/420IN1
A/COM
420IN2
CH1CH2
E‐NET
LOCA L 
SENSOR
TO DISPLAY
RED:+18‐30VDCPower
BLU:4‐20mAAnalogOut
BLK:PowerCommon
WHT:HardwareZero
GASMAXCXGASMONITORREMOTEGDS‐IRSENSOR
CUSTOMER‐SUPPLIED4‐CONDUCTOR
SHIELDEDWIRING
#18GAORLARGERRECOMMEND