Understanding Smart Sensors - Nomads.usp

288 Understanding Smart SensorsTable 12.4Signal and Control Lines for the TII [9]Line Logic Driven By FunctionDIN Positive logic NCAP Transports address and data from NCAPto STIMDOUT Positive logic STIM Transports data from STIM to NCAPDCLK Positive logic NCAP Positive-going edge latches data on DINand DOUTNIOE Active low NCAP Signals that the data transport is active anddelimits data transport framingNTRIG Negative logic NCAP Performs triggering functionNACK Negative logic STIM Serves two functions: trigger acknowledgeand data transport acknowledgeNINT Negative logic STIM Used by the STIM to request service fromthe NCAPNSDET Active low STIM Used by the NCAP to detect the presenceof a STIMPOWER N/A NCAP Nominal 5-V power supplyCOMMON N/A NCAP Signals common groundCorrected readingsComputerCorrection engineComputerComputerNetworkRaw readingsNCAPRaw readingsSTIM= Calibration TEDSNetworkCorrected readingsNCAPCorrection engineRaw readingsSTIMNetworkCorrected readingsNCAPCorrected readingsSTIMCorrection engine(a) (b) (c)Figure 12.12 IEEE 1451.2 correction engine in the (a) computer, (b) NCAP, and (c) STIM.(After: [3, 10].)