PDA how to get a sample rate >1KHz

[Steimers]

I need to sample 9 channels of analog input from the NI DAQCard 6036E at a speed from 1KHz , better >5KHz, and save the data on the Pocket PC ,perhaps in the future to a SD Card. I am using an iPaq with an Intel PXA255 Processor, 128MB RAM, Microsoft Pocket PC Version 4.20.0 (Build 14053) and Labview 8.2 with the PDA module and DAQmx Base 2.1. The Problem ist, that I’am not abole to sample these Data faster then 30Hz.
I’ve tried to scan blocks with around the 100 samples instead of just one but with the increased blocks also the sample time increases. I don’t know what’s wrong, on a common PC with DAQmx it works but not on this PDA with DAQmx Base.
I hope that somebody can help me because it should be able to scan these channels faster.But I can’t see my mistakes at the moment.

[AmirG]

Hello Steimers,
if you are trying to acquire data faster then 30 Hz, do you get any error message? Also,have you ever tried to sample the data using one channel? Are you able to sample data faster then 30Hz?
Best regards,
AmirG

[Steimers]

Hello,

thank you for your reply. The sample time refers to the time the while loop needs to accomplish. For that I tried to read huge blogs of data -what works fine with the normal LV 8.2 but not on the PDA module (I would like to know why...). I will try to sample just one channel perhaps that will make it more fast but in the end I will still need to sample all 9 channels. I've read a few threads that some people sample with the pda module much more fast but I really have no idea how.. I've seen these examples and build my VI like those -and I also changed the sample time and so on at the DAQmx Base Task.

[AmirG]

Hello Steimers,
I think this information from a KnowledgeBase could be helpful.
The PDA has limited processing power and because of this is subject to such buffer overflow errors when the device cannot pull data from the analog input buffer before it is overwritten.
-Change the sampling rate and the number of samples acquired from the buffer each iteration.
-Do not use Waveform Charts. Instead, use a Waveform Graph or numeric indicators.
-Do not do extra data processing, communications, or file I/O in the same loop with the data acquisition.
-Read the data in as raw instead of double precision.
-Perform a finite acquisition instead of a continuous acquisition.

Best regards,
AmirG

[Steimers]

Yes, I think there are a few helpful things under those you posted. I will try it in the next days. At the moment I really read this data with double precision and save the data in the same loop for example so I hope that it will help to change things like this. I will post again when I tried it out.
Thank you again for your reply how I said I think it will be very helpfull.