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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.

  • Data Acquisition Toolbox™ does not support direct access to device onboard clocks for clocked sampling when using only digital input/output channels with a DataAcquisition object. For workarounds and information on clocked digital sampling, see the following topics: