Multifunction DAQ

cancel
Showing results for 
Search instead for 
Did you mean: 

TDMS reading time delay

Hello,

I'm starting with Labview, and I have some trouble to make it work properly. I use the student version 8.20.

I have a problem to set the reading time of a TDMS file , whose data must be sent by the analog output of a USB6009.

The project aims to record the signal of an electrocardiogram, and reproduce it later. I get the signal from the analog input of the USB6009, (10 samples at 500Hz) and write it in a TDMS data file (REC option ). Execution time loop last of 20ms (50Hz) . Then later, when the user wishes, he can read the TDMS data file (PLAY option) , and recovers the signal from the analog output USB6009.

As the DAQ assistant output can send only one sample at a time, the loop "PLAY" should go 10 times faster, to keep pace temporal signal (2ms-500Hz), but I can not set this parameter.

As a result, reading the data takes too long. So for 2 minutes of recording, it takes nearly 3 minutes reading the same data.

Does someone knows how to set the time to execute a while loop ? or, is it possible to record in the TDMS file the temporal data?

Thank you very much for your help.

Sincerely,


Sebastian Avila.
0 Kudos
Message 1 of 2
(2,836 Views)
Your TDMS file will read much faster if you use the NI_MinimumBufferSize option, or if you defragment the file after writing. See http://digital.ni.com/public.nsf/allkb/63DA22F92660C7308625744700781A8D.
Herbert
Message 2 of 2
(2,833 Views)