I'm doing repetitive measurements of the type described in the nidaq example DAQsingleBufExtTrig.C:
iStatus = DAQ_Rate(dSampRate, iUnits, &iSampTB, &uSampInt);
iStatus = DAQ_Start(iDevice, iChan, iGain, piBuffer, ulCount, iSampTB, uSampInt);
while ((iDAQstopped != 1) && (iStatus == 0))
iStatus = DAQ_Check(iDevice, &iDAQstopped, &ulRetrieved);
When using a 100 Hz external trigger, the above code can be repeated at nearly 100 Hz on our various ni hardware (PCI E-series and a DAQCard-1200) under windows 95/98/me, using appropriate parameters. Under Windows 2000 but otherwise identical conditions, the best rep rate I can do is in the low 40s. I wouldn't have been too surprised if the roles of (2000/xp)
and (9x/me) were switched, but as it is I don't know why this is happening. Any ideas are welcome.