Understanding Smart Sensors - Nomads.usp

328 Understanding Smart SensorsSmartSimpleChemicalAdaptivemodulationFuzzy logicTransmission faultcorrection/recoveryLearned selfcalibrationPhoto transistorAdaptive calibrationPiezoelectricSynchronousdetection Lookup table Multidrop busdata transmissionMenu-drivenoperation guideCapacitivePiezoresistive IntegrationCorrelationCombinational logicDuplex digitaldata transmissionTransparentself-testHall effectThermistorPeakdetectionLinearfilteringCounting logicTiming logicSchmitt triggerthresholdingOther Amplification ThresholdingTransducerSignalconditioningDatatransmissionLatching shortcircuit protectionShort circuit andoverload protectionTransient clampingcurrent limitOutputtransmissionSignal strengthindicationLED indicatorsPotentiometersSwitchesSetup andmaintenanceinterfaceFigure 14.8 Smart sensor relative IQ. (After: [26].)manufacturers will apply the term smart sensor to a product even if it does notmeet an industry definition. But customers selecting the sensors that directlyaffect the performance and value of a product will determine the truly smartsensors. It is hoped that this book has in some manner provided guidance tomanufacturers and users of smart sensors to understand their potential in controlsystems.14.7 The Smart LoopSmarter sensors require adding intelligence to the sensor. The easiest way toadd intelligence is by using a microcontroller to provide computing capabilityand digital communication. Eventually, a monolithic combination of thosetechnologies will be mass producible. In contrast, smarter systems requireunderstanding more about the system and the environment. In real time, thatknowledge must be accumulated from sensors that provide more informationto the computing portion of the system, such as the smart airbag system mentionedearlier in this chapter. Figure 14.9 shows the continuum that exists asfuture sensors get smarter and sensors are added to controllers. Microsystemsneed smart sensors. Systems, in general, will benefit from smart sensors. If westart at any point on the continuum and add an increasing amount of smarts tosensors or more sensor inputs to the digital controller, the system moves theoperating point from one perspective to the other. In either case, the systemand users of the system benefit.