"error -200621" trying to generate 20 kHz sinewave on AO0:1 of PXI-4461 board

[Ov_metas]

Hello!

I am getting an -200621 error trying to generate a 20 kHz sinewave signals at the output 0 and 1 of a PXI-4461 board! The signal is generated during few seconds and then the error "Onboard device memory underflow..." occurs! Why? and How can I avoid it?

If  I am generating 1 kHz or using only one channel, everything is fine!

I joined the vi as well as the error message.

Below is the configuration of my system: 

Labview 8.5

PXI-1044 chassis with 14 slots and MXI-4 board (optical) to communicate with the PC:

- Slot 2: NI PXI 4461

- Slot 3: NI PXI 4461

- Slot 4: NI PXI 2561

Computer:

- Intel Core2 Quad CPU Q9400 2.66 GHz

- 3.49 GB Ram

I thank you in advance.

Frederic

[PeterAdelhardt]

Hi Frederic,

as you have already discussed with my colleague Laurent Pollara-Brevart, in your example VI the number of samples is simply too low. Therefore, the buffer is not getting updated quickly enough (updating 10 samples at 20kHz only leaves 0.5ms for each update). That is why it is running out of samples, eventually. Increasing the number of samples (e.g. 1000 or more) for this sample rate is the solution. Thus, the buffer does not need to be updated in such short intervals.

While this KB refers to the traditional DAQ driver, it explains the behavior you observed.

Hope this helped.

Best regards, 

Peter

[Ov_metas · Accepted solution]

Hi Peter,

The problem is indeed solved increasing the number of sample that are writen into the buffer!

Thanks to you and to Laurent!

Frederic