Manual

10of16 MN301035 RevB
GETTINGSTARTED(continued) StepSix
Howtoconfigureapanelmeterwhenapressuretransmitterisused?
This method works with the LI55 series, LI25 Series, LI10 Series and LI50 Series.These panel meters are
configured using the SCALE function.The SCALE function typically has four settings.These settings are as
follows:
Settings Default Represents TypicalSetting
Input1 04.000 Inputcurrent@Empty 04.000(mA)
Display1(Empty) 04.000 Displayvalue@Empty Emptyvalue
Input2 20.000 Inputcurrent@Full 20.000
Display2(Full) 20.000 Displayvalue@Full FullValue(mA)
Remember, pressure transmitters are configured so 0 psi = 4 mA and the maximum psi = 20 mA.Most
pressure transmitter applications will not use the full range of the transmitter and requires you to
proportionallyscalethecurrentoutputofthepressuretransmitter.Therefore,afulltankwilltypicallyhavea
currentlessthan20mA.Thegoalinconfiguringthepanelmeteristocalculatethecurrentwhenthetankis
full.Todothis,usethefollowingformula:
(FullTankHeight/MaximumLiquidHeight)x16+4=CurrentatFull
Example:A40foottankwithaSG=0.9willhaveamaximumpressureof15.58psi.A20psisensorisselected
foruse.TheMaximumLiquidHeight =(20psix2.31’/psi) /0.9=51.33feet.Usingtheaboveformula,the
CurrentatFull=[(40feet/51.33feet)x16+4]=16.468mA.
TheCurrentatFullwillbeusedastheInput2value.Thismeansthatwhenthedisplayreadsacurrentequal
toCurrentatFull,itwilldisplaytheFullvalue(Display2value).Thepanelmeterwillbeconfiguredasfollows:
Settings Configured
Input1 04.000
Display1 Empty
Input2 16.468
Display2 Full
Note:ThevaluesforemptyandfullrepresentwhatthedisplaywillshowwhenthetankiseitherEmptyorFull.
EmptyandFullmustbethesameunits(example:Gallons,Inches,percent).
 ThedefaultfortheInput1is4mAandtypicallywillneverbechanged.
 Typically,
theEmptysettingwillbewhatisinthetankwhenitisempty(example:000.0Gallons,000.0
inches,000.0feetetc.).
 TheFullsettingwillbewhatisinthetankwhenitisfull(example:500.0Gallons,120.0inches,10.0
feet,etc.).
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