DAQmx Error -200279 when opening remote desktop connection

[ytcui]

Hi, I am getting a DAQmx error -200279 (Attempted to read samples that are no longer available) when I try to connect to my acquisition computer with Windows remote desktop. The acquisition computer is running a continuous acquisition task, and whenever I log in using Windows remote desktop, this error pops up and the acquisition does not read data any more. Does anyone have a fix to this problem?

DAQ card: PCI 6052E

Labwindows ver 8.5

DAQmx ver 8.8

Windows XP

Error Code: -200279

Attempted to read samples that are no longer available. The requested sample was previously available, but has since been overwritten.

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[ManLongAtNI]

Does the error occur whenever you use Remote Desktop or is the application continually running and then you use RemoteDesktop to view the PC and then it throws the error.

Error -200279 explained

[ytcui]

The error occurs whenever I use the Windows Remote Desktop (RDP) to connect while the daq task is already running. After I log in remotely, I can start and run DAQ task with no problem. And it runs all ok after I disconnect RDP. But if I reconnect again before the task finishes, the error will pop up. It looks like establishing RDP connection somehow interrupts the daq and data in the cache got lost.

[Seth_B.]

What is likely happening is that it takes a good portion of your CPU to maintain your acquisition rate and establishing a RDP connection is using more CPU than the acquisition can spare.  What rate is your acquisition acquiring at and how many samples are your reading at a time (or are you just reading all available samples)?  Also, are you using the DAQmx read function in a loop?  If so, are you also starting and stoping your task in the loop?  It's best to start the task before the loop, read in the loop, and once your are done reading and have left the loop, stop the task.

Regards,

[ytcui]

My acquisition rate is 10K. I am running a continuous acquisition task and configure a callback function to process the acquired data every 1000 samples. 

I just checked the CPU usage. The DAQ computer has a quad-core CPU. The DAQ task consumes about ~10%. After I log in with RDP, the explorer.exe is consuming 25% of CPU, which means one CPU core is fully ocuppied by the RDP connection. I didn't realize the RDP can eat so much CPU. I thought Windows would allocate the new RDP connection to another spare core other than the one busy running the DAQ task. Do you have a fix to this? Thanks.