Справочник Пользователя для National Instruments Welding System 321645c-01
Chapter 2
Function Reference — WFM_DB_HalfReady
NI-DAQ FRM for PC Compatibles
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National Instruments Corporation
Using This Function
Double-buffered waveform generation functions cyclically output data from the waveform
buffer (specified in
buffer (specified in
WFM_Load
). The waveform buffer is divided into two equal halves so that
NI-DAQ can write data from one half of the buffer to the output channels while filling the
other half of the buffer with new data. This mechanism makes it necessary to write to both
halves of the waveform buffer alternately so that NI-DAQ does not output the old data. Use
other half of the buffer with new data. This mechanism makes it necessary to write to both
halves of the waveform buffer alternately so that NI-DAQ does not output the old data. Use
WFM_DB_Transfer
to transfer new data to a waveform buffer half. Both of these functions,
when called, wait until NI-DAQ can complete the data transfer before returning. During
slower paced waveform generation operations, this waiting period can be significant. You
can use
slower paced waveform generation operations, this waiting period can be significant. You
can use
WFM_DB_HalfReady
to call the transfer functions only when NI-DAQ can make the
transfer immediately.
Refer to the Double-Buffered Waveform Generation Applications section, in Chapter 5 of the
NI-DAQ User Manual for PC Compatibles, for an explanation of double buffering.
NI-DAQ User Manual for PC Compatibles, for an explanation of double buffering.