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PavementInstrumentation and DataAcquisitionLTRC’s Pavement Research FacilityPort Allen, LA
Centerpiece of DataAcquisition
Megadac 3415AC
Modules. 4 Input Channels. 4 Independent Analog Output Channels. Integrated Voltage Excitation, and Signal Conditioning. 10 Volts Full Scale (Input & Output).(Up to 210 Volts). Computer Controlled: Gains from 1 to 4000,Sensor Excitation Programmable 8-pole FilterVCAL & Shunt CALAuto Balance & Auto Zero. Increased Balance Range. Remote Sense for Excitation. Full Differential Inputs. Simultaneous Sample & HoldAD 694SH. Unipolar Excitation. Input Protection. D-Subminiature (37) Pin Connector Kit
Data Acquisition SoftwareTEST CONTROL SOFTWARE (TCS)zzzzOptim’s Test Control Software (TCS) operates on Windows. 95/98/NT platforms.A true 32-bit application,TCS is designed to take full advantage of today’s most powerful desktops,notebooks and computer workstations.No programming skills are necessary, since TCS is a fully integrated packagesimplifying the entire process of definingMEGADAC test setups and converting results into valid information.
Easy Set-up & MeasurementIn addition to user definedsample rates, TCS and theMEGADAC provide variousmethods to satisfy recordingcriteria. Recording can beinitiated via timers, by anoperator, through a remoteswitch, or with intelligenttriggers where data valuesexceeding thresholdsautomatically initiaterecording.
Test DefinitionTag NameMin/Max RangeEngineeringUnitsGain&ChnlGainSensor Calibration
Data CollectionTCS provides sensor libraries to simplify the entire process ofconverting digital and analog voltage signals into engineering unitterminology. Sensors can be categorized based on measurementtypes, ranges, manufacturers or capabilities.
Gauge Layout¾ Base9CourseTokyo Sokki KM 5000 EmbedmentStrain Gauge¾ SubbaseTokyo Sokki KM 5000 EmbedmentStrain Gauge9 Geokon Model 3500 Earth Pressure Cell9¾ Embankment9Geokon Model 3500 Earth Pressure Cell
Data As CollectedPressure CellsStrain Gauges
Typical Pressure Cell DataGauge @750K Passes20 Passes of ALFGauge located 12”below surface.Average psi 26.5
Single PassPressureCellThree secondsof data collection
Typical Strain Gauge DataGauge @750K Passes20 Passes of ALFGauge located 3.5”below surface.Avg uStrain 30
Single PassStrainThree secondsof dataGaugecollection
Operational Assessmentz Performanceof Megadac– No board failures– Consistent resultsz Performanceof Gauges– Eighty percent of all gauges still operationalafter 750,000 actual passes of AcceleratedLoading Facility (ALF)
Strain Gauge. ¾Subbase. 9Tokyo Sokki KM 5000 Embedment. Strain Gauge. 9. Geokon Model 3500 Earth Pressure Cell. ¾. Embankment. 9. Geokon Model 3500 Earth Pressure Cell. Data As Collected Pressure Cells Strain Gauges. Typical Pressure Cell Data Gauge @ 750K Passes 20 Passes of ALF Gauge located 12"
