Bending Stress Measurement System and Procedure for Experimental Training of Undergraduates on Electronics and Measurement Techniques

Anaccuratetrainingonmeasurementtechniquesandmeasurementsystemdesigncanbeobtained� b ycarryingoutrealexperimentswithrealelectroniccomponentsandcircuits.� Themeasurementsystem� presentedinthispaperperformsthecomputeraidedstudyofthebendingstresssensor.�Thisexperimental� systemisveryusefulforengineeringundergraduatesbecausetheycantestthetheoreticalknowledgeabout� measurementtechniques,�sensorsandtransducers,�signalconditioningcircuits,�dataacquisitionboards,�signal� processingmethodsandcomputers�(hardwareandsoftware).�Thebendingstresssensorconsistsoffourstrain� gaugesconnectedinafull>bridgecircuit,�andittransformstheloadorforceintomeasurablevoltagechange.� Aninstrumentationamplifierandanoisesuppressioncircuitandamplifieraredesignedforconditioningthe� outputvoltageofthebendingstresssensor.�Thecomputeraidedstudyofthissensorimposesadataacquisition� boardwithamicrocontroller,�adequatesoftwareandafriendlyuserinterface.�Theprocedureforstraingauge� sensorstudysupposesthefollowingfourstages:�assignationofthemeasurementpoints,�plottingthetransfer� characteristicoftheforcetransducer,� computingsomeparametersoftheforcetransducer� (zeroerror,� differentialsensitivity,� relativesensitivity),� weighingsomeobjectsusingthestraingaugesensors.� The� architectureanddesignconsiderationsforsignalconditioningmoduleanddataacquisitionboardarealso� presentedinthispaper.�