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Chapter 2
Function Reference — DAQ_DB_HalfReady
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National Instruments Corporation
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NI-DAQ FRM for PC Compatibles
Using This Function
Double-buffered data acquisition cyclically fills a buffer with acquired data. The buffer is
divided into two equal halves so that NI-DAQ can save data from one half while filling the
other half. This mechanism makes it necessary to alternately save both halves of the buffer
so that NI-DAQ does not overwrite data in the buffer before saving the data. Use the
divided into two equal halves so that NI-DAQ can save data from one half while filling the
other half. This mechanism makes it necessary to alternately save both halves of the buffer
so that NI-DAQ does not overwrite data in the buffer before saving the data. Use the
DAQ_DB_Transfer
function to save the data as NI-DAQ acquires it. This function, when
called, waits for the data to become available before retrieving it and returning. During slower
paced acquisitions this waiting period can be significant. You can use
paced acquisitions this waiting period can be significant. You can use
DAQ_DB_HalfReady
to ensure that the transfer function is called only when the data is already available.