Data Acquisition

[MartinBioeng]

I am using DAQ Assistant to drive a triangular and sine waveform and record the resulting current. So basically analogue in and one analogue out channels are used. The output waveform is a sine wave (100 Hz) moving up and down a triangular wave (1Hz). The DAQ Assistant is set to 10000 samples per second and 10000 for the No of samples and is set to continuous. When the "Integer No of Cycles" box is unticked the input waveform looks fine but it looks like the output waveform inverts after 10000 points. If the the samples per second is changed to 7000 the ouput waveform inverts after 7000 points. The data recorded to a text file has three columns: time, voltage out and current in which is ok. However, when  "Integer No of Cycles" box is ticked the no of columns starts at three but then goes back to two columns (time and input current) and then back to three columns again and so on.. But, additionally, the input current waveform looks fine without any inversion problems when the "Integer No of Cycles" box is ticked. Can anybody help?

thanks,

Martin

[TimM(AE)]

Hi Martin

I have been looking at your problem don’t quite get your set up can you post your code and what software versions you are using. Are you using any hardware or are you just simulating it if you are what are you using.

Regards

Tim

NI UK tec support

[MartinBioeng]

Tim,

Thanks for your reply. I have sorted the problem out by using the "multi-function AI-AO program" and adjusting the no of samples and sample rate to suit the recorded input frequency.

thanks,

Martin