Siemens LMV51.140C1 - Page 194

TechnicalInstructions  LMVSeries
DocumentNo.LV5‐1000
Section6 Page22SCCInc.
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barometricpressurethatexistedduringO
2
ControlCurvecommissioning,themanipulatedvariablemust
changetokeepthesame%O
2
inthestack.AnexampleisdonebelowandillustratedinFigure6‐9:
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AirtemperatureduringO
2
ControlCurvecommissioning=80°F
BarometricpressureduringO
2
ControlCurvecommissioning=30.0inHg
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Maximumexpectedairtemperature=120°F(+40°Fcomparedtocommissioning)
Minimumexpectedairtemperature=30°F(‐50°Fcomparedtocommissioning)
Maximumexpectedbarometricpressure=31.5inHg(+1.5inHgcomparedtocommissioning)
Minimumexpectedbarometricpressure=28.0inHg(‐2.0inHgcomparedtocommissioning)
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UsingFigure6‐8andtheinformationabove,thefollowingvaluescanbefound:
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O2MaxManVariable=13
O2MinManVariable=‐16
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Sinceothersmallfactorsexistthatcanchange(heatingvalueofthefuel,changeindraft,etc.),itis
suggestedthatanadditional5%areaddedtothemaxandsubtractedfromthemin,givingthefollowing
settings:
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O2MaxManVariable=18
O2MinManVariable=‐21
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Figure6‐9:FindingtheTheoreticalMaxandMinManipulatedVariableforGivenConditions
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