LabVIEW

cancel
Showing results for 
Search instead for 
Did you mean: 

audio sampling rate issue using USB 6008

Hello,
         I'm trying to input audio into the analog ports of my DAQ 6008. I'm using labview 8.5, and generated the DAQ assistant (express), used array index to output the 4 microphone channels into the waveform chart IV (i.e. I'm display 4 charts for the four analog microphone inputs). 

when I run it, the charts, on the screen, update every 1 sec it seems, which is MUCH slower than I would like to sample at (I perfer the max, of around 10K/s).   does anyone know why it's sampling so slow, and how I can improve this?

thank you,
dave

0 Kudos
Message 1 of 6
(3,032 Views)
note!  i have it all in a while loop.


thanks
dave

0 Kudos
Message 2 of 6
(3,031 Views)
one more point, in the DAQ assistant i am continuously sampling at 2.5 Khz (the max for the 4 channels I'm using).  On this editor screen, I see a much faster sampling rate than I see on the waveform chart, and in the file I port the data to (using auto indexing outside the loop)
0 Kudos
Message 3 of 6
(3,025 Views)
insure that your daq assistant step is set up for reading blocks of say 1/2 second.  Also use a waveform graph display rather than a chart - this is faster.
Preston Johnson
Solutions Manager, Industrial IoT: Condition Monitoring and Predictive Analytics
cbt
512 431 2371
preston.johnson@cbtechinc
0 Kudos
Message 4 of 6
(3,012 Views)
i cannot use waveform graph instead of chart, becuase i'm gathering scalars, and waveform graph requires at least 1D array data.  Also, in DAQ assistant, how do I set these blocks your refering too?  The only sampling options i see are sampling type (i.e. continuous), samples (which doesn't matter for continuous sampling), and rate (which I've maxed out at 2.5k).


In the DAQ assistant, the rate of data is being displayed at the correct rate, but in the front panel, and in the file I'm writing too, I'm see only about 1-2 data poins per sec....

below is a copy of my VI  (note, the system automatically insets a dynamic to array converted.

thank you!
dave



0 Kudos
Message 5 of 6
(2,986 Views)
If you have really set up the DAQ Assistant for continuous sampling and that rate, then you are not gathering scalars. The only reason you have scalars is the incorrect use of the Convert from Dynamic Data and the Index Array function. You would actually be returning an array of waveforms - not a 1D array. With dynamic data, all you would need to do is use the Split Signal function and wire up 4 separate graphs.
0 Kudos
Message 6 of 6
(2,977 Views)