Improve speed of acquisition

[akkasinadhuni]

Hi,

I am using a NI-USB 6356 for recording data at 1MHz. My experiment involves acquiring 256 RF waveforms where each RF waveform occurs 500 ms apart in time.

I created a task which uses an analog edge trigger to capture when the RF waveform occurs and then acquiring data only for about 5 ms which covers length of the RF waveform. This task works as expected. I then made a VI where I feed this task to a DAQmx read block and then write out the waveform to a delimited spreadsheet and also plot it on a graph. I loop over this process so that I expect to collect 256 files each one corresponding to an RF acquisition. Note that I had to put in a Clear Task block as well in order to make my loop work properly. The plot clearly shows me the output for each of the RF wave forms that are incoming.

However, when I run this experiment, I am seeing varying number of files. Sometimes, 265, sometimes 246, sometimes 241 etc. I am wondering if this is because the DAQ system is unable to write files at the speed at which it is recording the data. Although, have 265 files once seems like it might not be a speed issue.

I have attached my diagram file if my explanation was not complete.

Any thoughts? Your help will be greatly appreciated. 

Regards

Aditya.

[dmysliwiec13]

Hi akkasinadhuni, 

When you say you are using the USB 6356 to measure '256 RF waveforms', are these waveforms just analog signals at 1MHz?

Would you be able to attach the VI itself?

- I am not as familiar with the NXG icons, and can't remember what the top one is called. Posting the VI would help with this! Thanks!

Best,

Danielle

Applications Engineer 

[akkasinadhuni]

Hi Danielle,

That is correct. The RF waveforms are continuous analog signals fed through the AI ports on the device. I tried to attach my project and it did not let me. Hence I posted the screenshots. Unfortunately, I am not able to attach the gvi function file as well. 

Regards

Aditya.

[AgentAstronaut]

Hi Aditya,

The project should be in a folder in its own directory. Right click on the .lvproject item in the project explorer and select "Locate in Windows Explorer". This will take you to the folder containing the project. Go up one level in the file directory. Right click the project directory folder and select "Send to»Compressed Zipfile". Attach that here.

Cheers,

Michael