Memory underrun at Analogue Output with PCI-6025E card

[Jan-Mark]

When trying to output an analogue signal with a PCI-6025E card I get the following error:

Error - 10843 occured at AO Buffer Write

Possible reasons:

NI-DAQ LV: Because of system and/or bus-bandwidth limitations, the driver could not write data to the device fast enough to keep up with the device throughput; the onboard device memory reported an underflow error. THis error may be returned erroneously when an overrun error has occured.

For generating the signal (sine wave) I use a standard function generator that is in the DAQ Solutions section. By decreasing the waveform length I can avoid the error to occur, but the quality of my signal gets too bad. I used this function before on an
other system and I had no problems then.

Can anybody advise on how to avoid this memory underrun? Many thanks in advance for your reaction.

Kind regards,
Jan-Mark

[LucaP.]

Hi Jan-Mark

The main reason for this is because the 6025 do not has a FIFO buffer for AO operations. Please review the KB linked below for more informations:
http://digital.ni.com/public.nsf/websearch/72E6F81638BCDF0F86256B4A0082CCBC?OpenDocument

Regards,
Luca

[Jan-Mark]

Hi Luca,

Thanks for your reaction. I know my card doesn't have a FIFO buffer for AO operations. The question remains how I can avoid the error.

The answer might be in the link you sent me, but I can't open it.

Maybe you can give me some new advise on how to solve this problem.

Kind regards,
Jan-Mark

[LucaP.]

Hi Jan-Mark

That's really strange that you cannot open the link. Anyway, I've copied the content of the KB.

"Problem: I am running the Function Generator Example VI using my Low Cost PCI E-Series board, when I get error -10843 in LabVIEW. Why is this happening and how do I avoid it?

Solution: The Low Cost E-Series devices do not have a FIFO (first in first out) buffer for analog output operations. This means that the output speed will be severely limited by the speed of the bus and the overall speed of the PC. Error -10843 informs the user that NI-DAQ cannot keep the analog output at the specified rate because the PC cannot process the interrupts fast enough.

To get around this, try slowing down the update rate of the output. This is d
one by changing the update rate control on the front panel.

Another solution would be to force the device to use Direct Memory Access (DMA) for analog output operations. This can be done by using Set DAQ Device Information.vi, which can be found in the Functions Pallette under the Data Acquisition » Calibration and Configuration sub-pallette. DMA's allow data to be moved from one location to another in a computer without intervention from the CPU. Before using this option, make sure that the device can support DMA operations and has DMA's available for use. This information should be listed under Appendix A of the User Manual of the device.

As a final solution, use a faster machine to perform the operation."

Regards,
Luca

[Jan-Mark]

Hi Luca,

Thanks. This clearifies things. I will try to use DMA. I'll let you know if I manage.

Thanks again!

Jan-Mark