Hello,
From what the help says, it means that on a single channel the maximum rate R you can achieve is half the maximum rate specification Rmax. But for multiple channels in that case should be R/N.
My suggestions would be, in that case, use the low level functions. Many many examples are there in c:\program files\national instruments\ni-daq\examples\visualc folder.
The array dimensions will be (no. of channels, no. of samples per channel). If you are acquiring form 6 channels at 500 samples per channel, then the dimensions will be (5,500).
Sincerely,
Sastry V
Applciations Engineer
National Instruments