Try reading the data as a waveform and then inspect the "dt" field. I'll bet DAQmx is automatically coercing to the highest *supported* sample rate without throwing an error. (Though perhaps there's a warning?).
It's a pretty common (but not universal!) behavior for DAQmx to coerce inputs to the nearest legal, supported value.
-Kevin P
ALERT! LabVIEW's subscription-only policy came to an end (finally!). Unfortunately, pricing favors the captured and committed over new adopters -- so tread carefully.
