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National Instruments Hardware Limitations

  • Required hardware drivers and any other device-specific software is described in the documentation provided by your hardware vendor. For more information, see NI-DAQmx Support from Data Acquisition Toolbox.

  • You can use PXI_STAR with the addtrigger and addclock 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 attempt single scan (on-demand) operations:

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

    • If you then try to access that subsystem in a different MATLAB DataAcquisition, or any other application from the same computer, you might receive an error message informing you that the subsystem is reserved. Use release to unreserve the subsystem from the other DataAcquisition.

  • 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 channels in a DataAcquisition, when you start it you achieve 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.


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. For more information, see the supported hardware page at