How do I verify that I don't last any point during acquisition?

Question

Hello,
I need to make a continuous data acqusition using NI PXIe 5162 card it's why I wonder if there is a property node in labview or a program that shows if I lost any point during the acqusition??
I really need the answer !! thank you
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Answer 1

Hajar8,
When you start an acquisition, all the samples are stored into onboard memory in a circular buffer.  You then use "niScope Fetch" to request the data from memory, and the samples are sent via DMA to the host and to your application.  Since the buffer is a circular buffer, if you don't fetch the records fast enough (or the sample rate is too fast), then its possible for the acquisition to fill up the entire onboard memory, and then begin overwriting the old samples.  No error is thrown when this occurs when using the PXIe-5162.  Instead, when you attempt to fetch data that has been overwritten, the "niScope Fetch" VI will return the following error:
"Error -107411863 occurred at niScope Fetch....
Possible reason(s):
The requested data has been overwritten in memory so it is no longer available for fetching."
I hope this helps.
-Nathan
Product Support Engineer
National Instruments