NI 6009 analogue output

[durham_student]

Hi All,

I have a couple of problems with my NI 6009 USB DAQ:

1. In labview connecting the DAQ assistant (configured for analogue output) to a sine generator leads to two problems:

- The actual output when viewed on an oscilloscope is discrete (each wave consists of 8 peaks) rather than a continous spectrum. (Generator set to output 1 point)

- If I set the sine generator to output 1000 data points there is an error generated "the number of items in the data [input to DAQ] is not the same as the task".

Telling the DAQ to output continous data (attempting to match data and task) results in an error - "can only select 'OnDemand'"

2. The noise on the analogue inputs is of the order of 10's of mV, this rather seems to defy the object of having a 14-bit input with accuracy of 3mV. (+/-5V)

LabView is a testing stage before we move to python wrapped C drivers, but we need to prove that the device actual does what it claims to before we can move on.

Please can the knowledgeable readers advise.

Regards,

Durham_student

[Dennis_Knutson]

I'm not sure what you think the device claims to do but the specs state that the analog output is strictly software timed and can only do a max of about 150 updates/sec. You cannot write more than a single point and you cannot select continuous data. See this kb article.

[durham_student]

Thanks for the reply,

~150Hz might do the trick, but I'm getting maybe 1Hz. The DAQ assistant is in a while loop and set to excecute as fast as possible.

I definately need it to hold the output voltage whilst data is taken in.

Thoughts? 

Message Edited by durham_student on 11-03-2009 02:24 PM

[Dennis_Knutson]

Have you tried the example that's in the kb I linked? That does not use the DAQ Assistant.