Error -50352 for buffer larger than 4 MB

[danamics]

I am using a PCI-6254 on a Dell Precision 390 workstation with the most recent version of NI-DAQmx drivers.   In both MATLAB and LabView, if I start an analog input task with a buffer greater than 4 MB I get error -50352. This happens regardless of sampling frequency, number of channels, or task duration, as long as the buffer is greater than 4 MB.  I   Is there a way to increase my buffer size?  I have 100s of GB of disk space and 3.25 GB of RAM so there should be plenty of space. 

Note this problem occurs even if i'm using the DAQ card for the first time after a reboot, so it's not that I have uncleared buffers.

Thanks for any help.

[hoffiz]

Hi,

Buffer is the space reserve in computers memory (RAM) for the acquisition of the samples, like the help says: “A buffer is a temporary storage in computer memory for acquired or to-be-generated samples. Typically this storage is allocated from your computer's memory and is also called the task buffer”.

In the “DAQmx Configure Input Buffer” function the buffer size is measure in samples per. buffer size (in samples per channel) is the number of samples the buffer can hold for each channel in the task. Zero indicates to allocate no buffer. Use a buffer size of 0 to perform a hardware-timed operation without using a buffer.  So in your case 4M is 4 millions of samples per channel.

Two points I would like to emphasis, DAQmx drivers 8.5 had a problem with setting up the buffer size bigger than 64 MB, (buffer size times per channel times 2 bytes per sample); it has been solved in newer version,  make sure you do have a version newer than 8.5.

Second why do you need to increase the buffer size one, are doing some kind of analysis that takes a considerable amount of time and you want to have enough space to save the variables before been able to read another chunk of samples? If this is the case a producer consumer (parallel) design in LabVIEW will help you with this problem.

I hope it helps