10-27-2020 11:11 AM
I have a USB-4431 that has been working for years using two analog input channels. It just recently started intermittently generating Error -20061 Onboard device memory overflow errors. It seems to work about half the time. The system is running Windows XP with LabView 2009 and DAQmx 8.9.5. The system is not connected to the internet, so no software has been updated for years and no hardware changes have occurred. I can of course get rid of the problem if I drop the number of samples below the buffer size or reduce the sample rate significantly. We have a spare 4431 and the problem also occurs with the spare. The system has been able to read the buffer at the desired rate and sample size for several years without problem. Do you have a suggestion as to why the system is suddenly unable to dependably avoid this error?
10-27-2020 09:25 PM
@labvken wrote:
I have a USB-4431 that has been working for years using two analog input channels. It just recently started intermittently generating Error -20061 Onboard device memory overflow errors. It seems to work about half the time. The system is running Windows XP with LabView 2009 and DAQmx 8.9.5. The system is not connected to the internet, so no software has been updated for years and no hardware changes have occurred. I can of course get rid of the problem if I drop the number of samples below the buffer size or reduce the sample rate significantly. We have a spare 4431 and the problem also occurs with the spare. The system has been able to read the buffer at the desired rate and sample size for several years without problem. Do you have a suggestion as to why the system is suddenly unable to dependably avoid this error?
Is there anything new on the USB bus? Is the device plugged into a hub? This can lower the USB bandwidth. Also check the task manager to see if there are any processes taking CPU cycles.
I consider the 4431 a low bandwidth product, 100kSa/s for four channels is not a lot of data. I have used them on more modern systems without any problems. You can try to increase the buffer size to see if that helps. Also consider testing your RAM with memtester or something similar. The RAM acts as a buffer, if there is something wrong with it, that might be the cause of your problems. That is why is may be intermittent, only when the bad RAM is used do you get a problem.
mcduff