PCIe device raw data ordering

[Oldbhoy]

Hi all,

I'm using a PCIe 6374 DAQ for analog voltage acquisition.

I'm interested in the raw data, not the actual voltage values for my application. Speed is critical: incoming data is reshaped into an image (sometimes witha a pseudo color mask) and its much quicker to display as a U32 RGB or U16/I16 grayscale image than to rescale the floating point voltage values first.

The application i'm developing might be used with different hardware so i'd like to make it as robust as I can in this regard. The NI-DAQ manual (link here) states the following regarding raw data ordering:

  "NI-DAQmx does not separate raw data into channels. It returns data in an interleaved or non-interleaved 1D array, depending on the raw ordering of the device. Refer to your device documentation for more information."

I've been looking for this information everywhere and I can't seem to find it in the PCIe board's documentation, or another USB device we have in the lab.

Does anyone know of a daqmx node or other means of ascertaining whether a device uses interleaving or not for raw data ordering?

[santo_13 · Accepted solution]

Assuming that you use LabVIEW, the raw data ordering is provided in the Help

[Oldbhoy]

Thanks for the quick reply.

I was using different settings for the DAQmx read vi (left on image below). The one on the right is what you're refering to I guess (found under Analog/Unscaled). Can I ask, are these the same data but one is simply a reordered version of the other?

I may have been making this more complicated than it needs to be. Would certainly simplify reshaping the data if the latter can be used instead

 

-Allen