06-06-2013 02:53 PM
Hello,
I am trying to acquire analog voltage information from 31 channels using two PXIe-6368 cards synchronized via master and slave concept. The data is continously streamed into an array of TDMS files (a new file is written every 1 million samples). I am able to save the data at sampling rates up to 100 kS/s/channel. However, beyond 100 kS/s/chan, I consistently get the 200279 error. Ideally, I would like to log the data at (up to) the maximum possible rate - 2 MS/s/chan. I have basically concocted my code using the examples provided by NI (one for DAQ board synchronization and one for continuous TDMS file writing). I have tried most of the strategies shown in this article as well as in several related forum posts but I haven't been able to solve this problem. I would greatly appreciate any help in this matter.
Thanks,
Suhas
06-07-2013 03:59 PM
Hi, here you can find a description to the problem. I recommend opening the NI Example Finder and look at the example located in: Hardware Input and Output»DAQmx»Analog Input»Voltage - Continuous Input. Increase the buffer as mentioned in here (use 20M) and the problem should go away. I hope this helps
06-08-2013 06:10 PM
I meant to link the very same article you have provided but I prpbably forgot to actually create the link.In any case, yes, I have read through the article and tried a few tricks.
The most helpful fix was to increase the number of samples / channel to 10 million. Regardless, i am still limited to about 125 kS/s/chan sampling rate. I would like to bump this number up to 1 MS/s/chan.
06-10-2013 09:27 AM
Take a look at the attachment. I increased my buffer and I'm able to run at 1 MS/s/chan.
06-10-2013 03:21 PM
I tried increasing the buffer using your suggested method. I must admit it has improved our acquisition performance quite a bit. However, at sampling rates >= 1 MS/s/chan, I can only acquire data for about 20 secs or less. I need to acquire data over a 4.5 min period (at most) and I am trying to bring this down. Are there any other tweaks I could use to avoid this error and continue sampling at high rates?
Thank you so much for all your suggestions
06-11-2013 10:11 AM
If the recommendations on the article linked above are not enough then what is left is to add more RAM to your PC or to use a faster computer, as explained here (see Part I). If you managed to read the samples from the buffer faster then the problem should go away.
06-11-2013 01:29 PM
We have a NI PXIe-1082 that already has a i7 quad core processor and I have upgraded the RAM from the provided 2 GB to the maximum allowable 8 GB. I am not certain that we are having hardware limitations.
In any case, for time being, we are able to manage since we can acquire at 500 kS/s/chan for > 4 mins. So, thanks for the help.