National Instruments 321645c-01 Manual Do Utilizador
Chapter 2
Function Reference — Lab_ISCAN_to_Disk
NI-DAQ FRM for PC Compatibles
2-276
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National Instruments Corporation
Using This Function
Lab_ISCAN_to_Disk
initiates a synchronous process of acquiring A/D conversion samples
and storing them in a disk file.
Lab_ISCAN_to_Disk
does not return control to your
application until NI-DAQ acquires and saves all the samples you want (or until an acquisition
error occurs). For the Lab and 1200 Series devices, when you use posttrigger mode, the
process stores count A/D conversions in the file and ignores any subsequent conversions.
error occurs). For the Lab and 1200 Series devices, when you use posttrigger mode, the
process stores count A/D conversions in the file and ignores any subsequent conversions.
Note
If you have selected external start triggering of the data acquisition operation, a
low-to-high edge at the EXTTRIG of the Lab and 1200 Series device I/O connector
input initiates the data acquisition operation. Be aware that if you do not apply the
start trigger,
low-to-high edge at the EXTTRIG of the Lab and 1200 Series device I/O connector
input initiates the data acquisition operation. Be aware that if you do not apply the
start trigger,
Lab_ISCAN_to_Disk
does not return control to your application.
Otherwise,
Lab_ISCAN_to_Disk
issues a software trigger to initiate the data
acquisition operation.
If you have enabled pretrigger mode, the sample counter does not begin counting acquisitions
until you apply a signal at the stop trigger input. Until you apply this signal, the acquisition
continues to write data into the disk file. NI-DAQ ignores the value of the count parameter
when you enable pretrigger mode. If you do not apply the stop trigger,
until you apply a signal at the stop trigger input. Until you apply this signal, the acquisition
continues to write data into the disk file. NI-DAQ ignores the value of the count parameter
when you enable pretrigger mode. If you do not apply the stop trigger,
Lab_ISCAN_to_Disk
returns control to your application because you will eventually run out of disk space.
In any case, you can use
Timeout_Config
to establish a maximum length of time for
Lab_ISCAN_to_Disk
to execute.