Error -200621 Internal Buffer Overflow on USB-6366

Updated Jan 11, 2019

Reported In


  • USB-6366

Issue Details

I get an internal USB buffer overflow error. I am trying to use 6 AI (Analog Input) at the maximum rate of 2MS/s and 2 AO (Analog Output) at 2MS/s. The device is specifications says 8 channels can be used at 2MS/s.


Possible solutions include:
  • Reducing the number of AO channels.
  • Reducing the number of samples acquired per second.
  • Using hardware with higher bandwidth such as a PXI System.

Additional Information

AO channels have additional data overhead in USB data acquisition. Even though 8 channels at 2MS/s is indicated as maximum rate this is for 8 simultaneous AI channels. Including AO channels will exceed the maximum data transfer rate for USB devices. If other devices are using the USB controller or you are using an external USB hub to connect your DAQ device, you may see an additional limit to the number of channels and rates you're able to acquire at.


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