GEODigitalTiltmeterUserManual
GEO-Instruments24CelestialDriveNarragansett,RI02882800-477-2506support@geo-instruments.comwww.geo-instruments.com
Copyright2017GEO-Instruments,LLC.AllRightsReserved.
DigitalTiltmeter 21January2017 1
Contents
Introduction........................................................2
Components.......................................................3
Installation..........................................................4
Zeroing&Reading..............................................6
ATCommands.....................................................7
DataReduction...................................................8
DigitalTiltmeter 21January2017 2
Introduction
ApplicationsTiltmetersareusedtomonitorsmallchangesininclination.Theyareidealformonitoringstructuralrotation,differentialsettlements,deformation,andconvergence.Typicalapplicationsinclude:
• Monitoringthestabilityofstructuresadjacenttoexcavations.
• Monitoringdeformationofshoringwalls.
• Monitoringthetiltofpiersandpiles.
• Monitoringdifferentialsettlements.
• Monitoringdeformationintunnels.
• Monitoringcompensationgroutinginrealtime.
Configurations• Tiltmetersarefixedtothestructureviamountingbrackets.Theflatbracketholdsthe
tiltmeterparalleltothemountingsurface.Theright-anglebracketholdsthetiltmeter90degreestothemountingsurface.Theright-anglebracketisalsousedtomounttiltmetersonfloorsandceilings.
• Tiltmeterscanalsobemountedonlow-profilebeamstomonitorrelativemovementbetweenanchorpointsateitherendofthebeam.Anarrayofbeams,eachsharingananchorpointwiththenext,canbeusedtomonitordifferentialsettlements,deformations,andconvergence.
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Components
TerminationResistor
TiltmeterwithMountingBracket
RS485toRS232Converter
BusCable
ConnectorPairswithscrewterminals
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InstallationMountingTiltmeters1. Chooselocationsfortiltmeter
2. Drillmountingholes,installanchors.
3. Checkthattiltmeterissecurelyfastenedtoitsbracket.
4. Securebrackettoanchors.Adjustthebracketsothatthetopofthetiltmeterboxislevel(horizontally)andfrontoftheboxisplumb(vertical).Fineadjustmentsaremadelater.
5. Notelocationofthetiltmeteranditsaddress(markedonthefrontcover).
PrepareBusCables1. Measuredistancesbetweentiltmetersandcutcableto
appropriatelength.
2. Cablehastwotwistedpairsandadrainwire.Onepairisforpower;theotherpairisforsignal.
3. Stripbackabout1inchofcablejacketand.25inchofinsulationfromeachlead.(25mm/6mm).
4. Findconnectorpairs(onescrew/onesocket)foreachlengthofbuscable.
5. Openconnectors.Slidebarrelsontoendofcablebeforeconnectingleads.
6. Connectleadstoterminals1through5intheconnector.ColorsareforGEOcable.
• Terminal1:5-12Vdc-red
• Terminal4:Ground-black
• Terminal2:SignalA-white
• Terminal3:SignalB-green
• Terminal5:drainwire.
7. Slidebarreldowntocoverterminalsandscrewtight.
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ConnectBusCablesbetweenTiltmeters1. Connectbuscablesbetweentiltmeters.
2. Connectterminationresistor(shown)totiltmeterfurthestfromthelogger.
ConnectRS485toRS232Converter1. Connect485bustoconverter.
2. ConnectRS232cabletoothersideofconverter.
3. Connect12Vdcpower.
ConnectRS232CabletoLogger• ConnecttheRS232cabletotheRS232portonthe
logger.
• Optionally,connecttx/rxandgroundintothe2xcommportsonthelogger.
• Loggercommportsettingsshouldbe9600baud,8bits,noparity,1stopbit.
RS232CabletoLogger
RS485Cabletotiltmeters
12vdcfrompowersupply
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Zeroing&ReadingZeroingtheTiltmeterThetiltmeterhasanarrowmeasurementrange,somonitoringshouldstartwithacompletelylevelsensor.
ZeroingDevice:AsocketisprovidedforazeroingdevicesuchasHELM,whichprovidesACexcitation.Notethat485boardmustbedisconnected.
CampbellLogger:Thetiltmetercanalsobezeroedthroughthe485bususingaCampbellScientificlogger.Inthiscase,“Zero”isapproximately32500Counts.Seeseparateinstructions.
ZeroingwithZeroingDevice1. Verifytiltmeterboxislevelandplumb.
2. Unplug485boardconnector(whitecircle).
3. Checkthatlockscrew(bluecircle)issnug,butnotfullytightened.
4. Plugzeroingdeviceintosocket(redcircle).
5. Adjustsensorcarrierupordownusingadjustmentwheels(bluerectangle).
6. Whenreadingisclosetozero,checkthatbothwheelsareincontactwithcarrier.Thencarefullytightenlockscrew.Checkthatreadingisstillclosetozero.Adjustasnecessary.
7. Removezeroingdevice.
8. Reconnect485boardconnector.
9. Applythread-lockingcompoundtokeepwheelsfrommoving.
ZeroingwithDataLoggerFollowsimilarsteps,butkeep485boardconnected.
StartLogging1. Closecovercarefullysopositionoftiltmeterisnotchanged.
2. Startloggeranditsmonitoringprogram.
485boardconnector
Socketforzeroingdevice
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ATCommandsCommandFormat*nnYY#• *isthestartofcommandstring.
• nnisthetwodigitsensoraddressforaparticularsensor:01through99.
• YYisthecommand.
• #istheendofthecommandstring.
DataCommands• *nn11#returnstiltdataas16bitasciivalue.(substitutesensoraddressfornn)
• *nn82Dreturnsuserinformationforsensornn.
• *nn41#returns10bitasciivalueforcalculatingboardtemperature.NOTE:Toconvertthe10bitasciivaluetodegreesC:
Calculate:Output=(x/1023)*5v(wherexisthe10bitasciivalue)
Thencalculate:TempC=(Output–0.5)/0.010
SetupCommands• *nn81Axx#setsaddressofsensornn.xxisanewvaluefrom01to99.
• *nn82Sxxxxxxxxxxxx#setsuserinformationforsensornn.12alphanumericcharacters.
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DataReductionCalibrationRecordThecalibrationrecordprovidesfactorsusedtoconvertrawreadingsfromthesensortoengineeringunits.Calibrationfactorsareuniqueforeachsensor.Usesensorserialnumberstomatchsensorswiththeircalibrations.
Duringthecalibrationtest,thesensorisfixedtoasinebarandrotatedthroughitsrangefourtimes.Thepositionofthesinebarismeasuredwithadigitalmicrometerandreportedinmm/m.Theoutputofthesensor(Counts)isrecordedateachpositionandabestfitcalibrationcurveisestablished,yieldingasetofconversionfactorstoconvertCountstoavalueinmm/m.
CalculatingTiltinmm/mTiltinmm/m=b0+b1X+b2X2+b3X3Where:b0throughb3arefactorsfromthecalibrationrecordandXisthereadinginCounts.
CalculatingTiltindegreesFirst,usethecalibrationfactorstocalculatetiltinmm/m,thenconverttodegrees:
Tiltindegrees=arcsine(tiltinmm/m*1m/1000mm).
CalculatingChangeinTiltΔTilt=Tiltcurrent–Tiltinitial
GEO-Instruments
24 Celestial Drive
Narragansett, RI 02882
Tel: 800-477-2506 [email protected]
www.geo-instruments.com
Instrument Digital TM Serial No 16007014 Factory Set ID 160070141701 Ambient Temp 19.40
Range ± 12 mm / m Equipment 60003705 Factory Set Address 1 Date 1/18/2017
-12.000 38390 38388 38387 38387 38388 -12.000 -0.001
-8.000 36577 36574 36578 36572 36575 -7.999 0.005
-4.000 34842 34868 34877 34875 34866 -4.003 -0.012
0.000 32909 32936 32950 32943 32935 0.003 0.014
4.000 30879 30909 30912 30913 30903 3.997 -0.011
8.000 29073 29078 29094 29090 29084 8.001 0.005
12.000 27447 27444 27468 27466 27456 12.000 -0.001
b0 b1 b2 b3 b4 b5
-9.56959E+03 1.53179E+00 -9.70089E-05 3.04834E-09 -4.76020E-14 2.95570E-19
Certified by
Fax: 401-633-6021
INSTRUMENT CALIBRATION CERTIFICATE
Reading = b0 + b1X + b2X2 + b3X
3 + b4X4 + b5X
5
Conversion Factors
(mm/m)/counts
Polynomial Gage Factors
Position (mm/m)
Raw Data (Counts) mm/m Polynomial
1 Up 1 Down 2 Up 2 Down Average Error %FS
Conversion Formula
Displacement = Current Reading - Initial Reading
Calculated mm/m
(where X is the raw sensor data in Counts)
Geo-Instruments certifies that this instrument has been inspected, tested, and calibrated. It conforms in all respects to our specifications and drawings.
-12.000
-10.000
-8.000
-6.000
-4.000
-2.000
0.000
2.000
4.000
6.000
8.000
10.000
12.000
25000 27000 29000 31000 33000 35000 37000 39000
mm
/m
Digital Counts
Digital TM
TM Counts
Poly. (TM Counts)
Anegativechangeindicatescounter-clockwise(anti-clockwise)rotation.
Apositivechangeindicatesclockwiserotation.