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DIO Read is not reporting correct backlog numbers

We're using a PCI-6534 DIO card with a VersaLogic Cheetah CPU to do some high-speed data acquisition using Labview 7.1.  The program appears to run fine for approximately 16 minutes at a incoming aggregate data rate of 4.5MB/s at which time it appears we are getting incorrect backlog data available numbers.  The value does not change for approximately 5.5 seconds at which time the program then realizes there is about 12.2 million 16-bit samples available to read.  We've verified that the loop this is running in is still running but for some reason the software cannot tell that data is available.  Can anyone tell me if this problem has been seen before?
 
We are using the DIO Read command with a '0' in the 'number of scans to read' field to check the backlog such that we can then read it when it gets to an appropriate size using a second call to DIO Read of the appropriate block size (about 400,000 samples in our case).
 
Thanks for your help.
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Hi,

Have you tried using one of the shipped examples and checked if the DIO adopts the same behavior.

It might be how you setup your software.

 

Regards,

Faris A

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