To provide greater ease of use and faster performancefor your data acquisition (DAQ) devices, NI offers anindustry-leading data acquisition driver framework,NI-DAQmx. The DAQ Assistant feature of NI-DAQmxdelivers a step-by-step guide for configuring, testing, andprogramming your measurement tasks. It also automaticallygenerates NI LabVIEW graphical code for low-levelcustomization. Together with Express VIs in LabVIEW, theDAQ Assistant makes it easier and faster to develop dataacquisition applications. The NI-DAQmx low-level drivercomponents enhance your measurement performance,so you can run multithreaded applications and controldifferent device functions simultaneously.
Getting Started with the DAQ Assistant
You can access the DAQ Assistant from the Expresspalette in LabVIEW. As soon as you drop the DAQ Assistanton a block diagram, a dialog launches to help youconfigure your measurement. Choose from preconfiguredchannel types including voltage, strain, current, pulsewidth, and digital I/O; then, let NI-DAQmx configure yoursystem for you. If a sensor type is not listed, build acustom scale to easily convert measurements to physicalunits such as pH, torque, or light intensity. Next, configurethe run-time behavior of your acquisition by settingsampling rate, number of samples to acquire, and customtriggering. Additionally, you can test your measurementtask from this dialog to verify that your settings arecorrect.
Figure 1. The DAQ Assistant helps you configure, program, and test
your measurement application.
After clicking OK, you return to the LabVIEW blockdiagram, and the DAQ Assistant changes its outputterminals to the proper data type. The DAQ Assistantnow automatically configures your DAQ system andperforms the acquisition or generation. You simply wirethe output into a graph or analysis VI and run yourprogram as demonstrated in Figure 2.
Figure 2. Use the DAQ Assistant and LabVIEW to easily
acquire, analyze, and present your measurements.
acquire, analyze, and present your measurements.
Easy LabVIEW Integration
The DAQ Assistant makes building data acquisitionapplications faster and easier than ever. For example,the DAQ Assistant can help you build a sophisticateddata acquisition application in less than 30 seconds.With just the DAQ Assistant, you can quickly build andrun your first measurement in LabVIEW. You canrelaunch the DAQ Assistant to quickly refine yourmeasurement program by changing parameters such assampling rates, triggering, and scaling.
Additionally, the DAQ Assistant integrates with powerfulanalysis functions in LabVIEW. As Figure 2 illustrates,you wire the dynamic strain measurement signaldirectly into the Spectral Measurements Express VI andselect your analysis. The waveform graphs on the frontpanel display the engineering units and time on the axisand automatically label the plots with the signal names.This integration between data acquisition and analysissaves you development time and improves the usabilityof your final application.
Code Generation with the DAQ Assistant
The DAQ Assistant is an interface to the NI-DAQmx driverframework from LabVIEW. While configuring a measurementtask, the DAQ Assistant communicates with aconfiguration manager to determine the measurementcapabilities of your device. When you finish configuringyour task, the DAQ Assistant generates subVIs thatcontain Data Acquisition VIs. At run time, those VIs usecomponents of the NI-DAQmx driver engine to control thedata acquisition hardware; synchronize different operations;stream data back to your PC; and present themeasurement in scaled, physical units.
The configuration dialogs of the DAQ Assistant give youpower over the underlying components. Because all thefunctionality is there, you can convert the DAQ AssistantExpress VI to standard, lower-level VIs.
For some advanced applications, such as changinghardware attributes while acquiring data or programmaticcontrol of hardware resources, you can use theDAQ Assistant as a starting point to generate anNI-DAQmx example program and then use additional VIsand properties to expand your application.
