Honeywell XNX Technical Manual

XNX Universal Transmitter
Section 3 - Calibration
97
3.2.8 Zero and Span Calibration for MPD Sensors
Caution: Extendedorfrequentexposuretoelevatedconcentrations
ofcombustiblegasesmayaffectsensorsensitivity.Verifysensor
performancebyfrequentcalibration.
Caution: Beforeinitialcalibrationallowthesensortostabilizefor30minutes
afterapplyingpower.Wheninzeroandspancalibrationmodes,thecurrent
outputfromthesensorisinhibited(default2mA)toavoidfalsealarms.
TheGasCalibrationmenuisforbothzeroandspancalibrations�
ThissectiondescribeshowtocalibrateMPDammablesensors
ttedtothetransmitter�Thecalibrationadjustmentsaremadeon
thetransmittersdisplay�Gassingisperformedatthesensor,
whichmaybelocallyorremotelylocated�
Thefollowingequipmentisrequired:
• Flowhousing(P/N:1226A0411)
• Testgas
• Regulator
Note:ZerogasandSpangasshouldbeataboutthesamehumiditylevelsto
avoiderroneouscellresponses.
1�AttheMPD,removetheweatherproofcap,ifequipped�
2�FittheowhousingontotheMPD�
Figure 214. Flow Housing
3�Reversethecapremovalprocedure�Figure215showsthe
owhousingaccessoryttedtotheMPD�
Figure 215. MPD with Flow Housing
4� Connecttheowhousing(usingeithergaspipe)tothe
regulatedcylindercontainingaknownconcentrationofthe
targetgasatapproximatelythesensoralarmpoint,e�g�,50%
LELmethaneinair�
Warning: Assometestgasesarehazardous,exhausttheflowhousingoutlet
toasafearea.
5�FollowtheprocedureinSection3�2�1forbothzeroand
spancalibrations�
6�Applythetargetgastothesensor�Passthegasthrough
theowhousingatarateof 300-375ml/minforXNXEC
sensorsor500±200ml/minforXNXmVsensors �

Honeywell XNX Specifications

General

Ingress Protection	IP66/67
Product Type	Universal Transmitter
Enclosure Rating	IP66/67
Display	LCD
Communication Protocols	HART, Modbus, Foundation Fieldbus
Power Supply	24 VDC nominal, 18-32 VDC
Operating Temperature	-40°C to +65°C (-40°F to +149°F)
Material	Aluminum or Stainless Steel
Gas Types	Toxic, Oxygen, and Combustible gases
Output	4-20 mA
Relays	3 programmable relays
Approvals	ATEX, IECEx, UL, CSA
Sensor Compatibility	Electrochemical, catalytic, infrared, and other sensor types