Honeywell XNX - Zero Calibration

XNX Universal Transmitter
Section 3 - Calibration
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3.2.1 Zero and Span Calibration for XNX EC Sensors,
mV Sensors, and Searchpoint Optima
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.
Caution:Formoststickygases(e.g.,HCl,Cl
2
)usePTFEtubingwithshort
piecesofrubbertubeforthefinalconnection(duetotheinflexibilityofPTFE).This
minimizesadhesionofthegastothetubesurfaceandallowsmoreaccurate
measurement.
Tocalibratethesensor,useanappropriatespangascylinder,
tubing,magnet,andcalibrationgasowhousing�Settheow
regulatorto300-375ml/minforXNXECsensorsor500±200ml/
minforXNXmVsensors�Acompressedgascylinder(20�9%Vol
oxygen)shouldbeusedtoperformthezerocalibrationifthe
areawherethesensorislocatedcontainsanyresidualamount
ofthetargetgas�Ifnoresidualgasispresent,backgroundair
canbeusedtoperformthezerocalibration�ContactaHoneywell
Analyticsrepresentativefordetailsaboutsuitablecalibrationkits�
Tocalibratethesensor,followtheprocedureinSection3�2�2�
Note: Theoxygensensordoesnotrequireazeroingprocedure.Background
air(20.9%Voloxygen)canbeusedtospantheoxygensensorinplaceofa
compressedaircylinder(20.9%Voloxygen).SeeSection6.3.2forothersensors.
Note: ENperformancestandardsrequire10minutesstabilizationtimefor
applicationofzeroandspangasforperformance-approvedEC,mV,andIR
sensorspriortocalibration.
3.2.2 Calibration Procedure
Thissectionoutlinesthestepsforcalibratingthetransmitter’s
attachedsensors�

Note: TheZeroCalibrationprocedureshouldbeperformedpriortotheSpan
Calibrationprocedure.
1�Ifusingacompressedgascylinder,pushthecalibration
gasowhousingontothebottomofthesensorandapply
thegas�
2�AccesstheGasCalibrationMenu�
Figure 194. Gas Calibration Menu
Note: TheGasCalibrationmenuisforbothZeroCalibrationandSpan
Calibration.
Zero Calibration
Sensor Reading
at Current Settings
Figure 195. Zero Calibration Screen