National Instruments Hardware

  • Required hardware drivers and any other device-specific software is described in the documentation provided by your hardware vendor. For more information, see Supported Hardware - National Instruments.

  • In the legacy interface, you should configure the SampleRate property with the setverify function just before starting the hardware. Note that the SampleRate value depends on the number of channels added to the device object, and the ChannelSkew property value depends on the SampleRate value.

  • In the legacy interface, only one digital I/O (DIO) object should be associated with a given DIO subsystem. To perform separate tasks with the hardware lines, you should add all the necessary lines to the DIO object, but partition them into separate line groups based on the task.

  • You cannot use PXI signals in the legacy interface of Data Acquisition Toolbox™ software. PXI signals are supported by NI 6281 PXI boards and by the Ni_DAQmx library, but are not available in the legacy interface. In particular, the ability to use the PXI_STAR signal for the HwDigitalTriggerSource property of the analog input object and the PXI_CLK10 backplane clock for the ExternalSampleClock property are unavailable. You can use PXI_STAR in the session-based interface with addTriggerConnection and addClockConnection functions. All supported PXI modules automatically use the reference Clock PXI_CLK10.

  • Objects created for National Instruments® devices, and used with the NI-DAQmx adaptor have the following behavior when you use the getsample, putsample, getvalue, putvalue, functions in the legacy interface and inputSingleScan, ouputSingleScan functions in the session-based interface:

    • The first time the command is used with the object, the corresponding subsystem of the device is reserved by the MATLAB® session.

    • If you then try to access that subsystem in a different session of the MATLAB software, or any other application from the same computer, you may receive an error message informing you that the subsystem is reserved.

      • In the session-based interface use release to unreserve the subsystem.

      • In the legacy interface delete the object in the first session of MATLAB before you can use it in the next one.

  • You cannot acquire and generate synchronous data using myDAQ devices because they do not share a hardware clock. If you have both input and output channel s in a session and you start the session, you will see near-simultaneous acquisition and generation. See Automatic Synchronization for more information.

  • NI USB devices that have their own power supply can shut down if the driver does not set the USB power correctly.

    Note:   The Traditional NI-DAQ adaptor will be deprecated in a future version of the toolbox. If you create a Data Acquisition Toolbox™ object for Traditional NI-DAQ adaptor beginning in R2008b, you will receive a warning stating that this adaptor will be removed in a future release. See the supported hardware page at for more information.

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