Analog data swaps channel when update rate is too high.

[Rolf_Weibull]

I am using PCI-6733 on a Dell Dimension XPS T500 with Windows NT.
I am running the LabVIEW example "Contiuous CDO with AO (E).vi" found in Hardware Input and Output > DAQ > Digital Input and Output > E-series. The only difference from this example is that I generate data on all 8 analog channels. I have also deleted the AO Write.vi and DIO Write.vi inside the while loop.

Below update rate 20kS/s it works OK, but when the update rate is faster than 30kS/s the data swaps between the channels. Data assigned for ch0 swaps between ch2, ch4, ch6 and data assigned for ch1 swaps between ch3, ch5, ch7.

If I delete the digital out from the vi, the analog out works OK at least up to 700kS/s.

Why does continuous CDO
with AO not work above 30kS/s?

[Spencer S.]

Rolf,

Very strange. Do you receive any errors or warnings? If you decrease the number of analog output channels, does this make a difference? Are you using DMA transfers?

Spencer S.

[Rolf_Weibull]

Spencer,
Thanks for your answer.
No, I don’t receive any errors or warnings.
I have decreased the number of analog outputs and with three or more analog outputs I get the same problem.
Yes, I use DMA.
I have also tried the 6733 on a Dell Dimension 4550 Basic, 2530 MHz with Windows XP, and I get exactly the same fault.
/Rolf W.