GEO Digital Tiltmeter · 2020. 2. 6. · Tilt in mm/m = b 0+ b 1X + b 2X 2 + b 3X 3 Where: b 0 through b 3 are factors from the calibration record and X is the reading in Counts

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


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.


Components

TerminationResistor

TiltmeterwithMountingBracket

RS485toRS232Converter

BusCable

ConnectorPairswithscrewterminals


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.


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


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


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.


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.

Documents

GEO Digital Tiltmeter · 2020. 2. 6. · Tilt in mm/m = b 0+ b 1X + b 2X 2 + b 3X 3 Where: b 0 through b 3 are factors from the calibration record and X is the reading in Counts