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Learn about data acquisition, measurement, and generation of physical signals in LabVIEW using NI-DAQmx for analog input/output, digital I/O, and counter operations. Explore DAQ system components, sensors/transducers, and signal conditioning units for various measurement types.
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Chapter 9Data AcquisitionMeasurement or generation of physical signals.
Data Acquisition in LabVIEW • NI-DAQmx • Next generation driver: • VIs for performing a task • One set of VIs for all measurement types • Traditional NI-DAQ • Specific VIs for performing: • Analog Input • Analog Output • Digital I/O • Counter operations
DAQ System Components> Sensor/Transducer> Signal Conditioning Unit> DAQ PCI Interface Card> Computer> Software Analyze & Display
Phenomena & TransducersTemperature Thermocouple Resistance Temperature Detectors (RTDs) Integrated Circuit SensorLight Vacuum Tube Photosensor Photoconductive CellsSound MicrophoneForce & Pressure Strain Gauges Piezoelectric Transducer Load CellsPosition Optical Encoder PotentiometersFluid Flow Head Meters Rotational FlowmeterspH pH electrodes
Signal Conditioning Circuits > Linearization > Excitation > Isolation > Filtering > Amplification
Sensors DAQ Device Computer Cable Terminal Block Data Acquisition M-SERIES • Data Acquisition (DAQ) Basics • Connecting Signals • Simple DAQ Application
NI USB-6009 14-bit Analog Inputs
Signal Types Digital: > On-Off > Pulse Train Analog: > DC > Time-Domain > Frequency-Domain
Signal Information > State > Rate > Level > Shape > Frequency
Signal Source Configuration > Referenced Singled-Ended RSE > Non-referenced Singled-Ended NRSE > Differential
Analog I/O Conversion Issues > Resolution > Range > Sampling Rate
ADC Resolution> Number of bits used to represent an analog signal.
RangeMinimum & Maximum analog signal levels that the ADC can handle.
Code WidthVCW = Range G x 2ResolutionThe smallest detectable voltage change by a data acquisition board with gain G.
Sampling Rate Samples of an analog signal Discrete points in time Sampling frequency – number of samples per second
Sampling Rate Aliased Signal Adequately Sampled Signal