PXI-6704 voltage output latency

[valic]

I have on old PXI-6704 and I want to generate 1 channel, 1 sample voltage output.

Everithng  is working as expected exept for the output latency. I can see all samples are generated (the update rate is 5ms bigger than the max of 1.8ms), but I can messure a delay of aprox. 50ms from the moment of  DAQmx Write and the Voltage generated.

Is there any method to configure the card to reduce the FIFO.  I alredy tried a lot of samples from people with similar problems but their solution did not worked on my PXI-6704.

Any suggestions will be mutch appreciated,

Thanks.

[Dado.MB]

Hello Valic,

I see that this instrument is software time, so maybe the OS is affecting your operation as it is non-deterministic.

I looked up the supported properties on your PXI 6704 and it seems it supports the "DAQmxSetBufOutputBufSize" and "  DAQmxSetAOUseOnlyOnBrdMem" properties for the output buffer, have you tried setting that to first one to 0 or set to use only on board memory?

You can look at the supported properties and descriptions here:

http://zone.ni.com/reference/en-XX/help/370471W-01/cdaqmxsupp/pxi-6704/

Regards,

David M.

National Instruments 

[valic]

Thank you David for your response,

I tried to set to 0 the Output.BufSize but get on unsupported error 200452.

Also when I set to true AO. UseOnlyOnBrdMem I get error 200077 indicating that I can only set to false this property.

My OS is LabView Real-Time 8.5 and I saw I can update DAQmx to version 9.3 and hope to have better results.

Or maybe I can access the card directly by VISA protocol which is something I have no experience (registers, comamnds, etc for this card).