15
states�Twoalarmlevelscanbeset,allowing,forexample,alevel
1alarmfortheimmediateareawhenacertaingasconcentration
isdetectedandaplant-widelevel2alarmwhenagreatergas
concentrationisdetected�
Themaximumrefreshrateoftherelaysis2seconds�SeeSet
AlarmValuesformoreinformation�
1.3.3 Modbus
TheoptionalModbusinterfaceallowstheXNXtoconnectto
abusofdevicesandtransmitdatatoPLCsorcontrollers�
(Formoreinformation,seetheModbus
ProtocolManual)�
ConnectionstotheXNXaremadethroughapluggableterminal
blockontheModbusinterfacecircuitboard�ModbusRTU
protocolusesASCII/Hexprotocolsforcommunication�
Note:PODoptionsareeitherrelay,Modbus,orFoundationFieldbus.
1.3.4 Foundation Fieldbus
FoundationFieldbusisadigitalcommunicationsystemwhich
supportsseveraltypesofmessages�Unlikemanytraditional
systemswhichrequireasetofwiresforeachdevice,multiple
FoundationFieldbusdevicescanbeconnectedwitha
singlesetofwires�FoundationFieldbusovercomessome
ofthedisadvantagesofproprietarynetworksbyprovidinga
standardizednetworkforconnectingsystemsanddevices�
1.3.5 XNX Accessories
Pipe Mount Kit
ThePipeMountkit(1226A0358)allowstheXNXtobemounted
topipefrom2”-6”(50-150mm)indiameter�Thekitincludesthe
pipemountbracket,twocarriagebolts,nuts,andlockwashers�
Figure 8. Pipe-mounted XNX Transmitters
Calibration Gas Flow Adapter
Thecalibrationgasowadapterisusedtoapplycalibration
testgastothesensor�Itattachestothebottomofthesensor
andcanbettedwithoutremovingtheweatherproofcover�See
Section3-Calibrationforfurtherdetailsongascalibration�
Sensor Flow Adapter P/N
XNX EC S3KCAL
MPD 1226A0411
Sensepoint 02000-A-1645
705 00780-A-0035