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Chapter 10 Easy I/O for DAQ Library
© National Instruments Corporation 10-17 LabWindows/CVI Standard Libraries
from the internal circular buffer, where n is scanstoRead. Calling AIReadAcquisition in
this mode resets the scanBacklog to zero.
scanBacklog returns the backlog of scans that have been acquired into the circular buffer but
have not been read using AIReadAcquisition. If AIReadAcquisition is called in
"latest" read mode, the scan backlog is reset to zero. You can also call AICheckAcquisition
to determine the scan backlog before calling AIReadAcquisition.
waveforms is an array containing the voltages acquired on the channels specified in the
channelString. The acquired voltages are placed into the array in the order specified by
fillMode. This array must be declared as large as:
(number of channels) * (scanstoRead)
You can determine the number of channels by using the function GetNumChannels.
AISampleChannel
short error = AISampleChannel (short device, char singleChannel[],
double highLimitVolts, double lowLimitVolts,
double *voltage);
Purpose
This function acquires a single voltage from a single analog input channel.
Parameters
Input
device
short integer Assigned by configuration utility.
singleChannel
string The analog input channel that is to be sampled.
highLimitVolts
double Maximum voltage to be measured.
lowLimitVolts
double Minimum voltage to be measured.
Output
voltage
double
(passed by
reference)
Returns the measured voltage.
Return Value
error
short integer Refer to error codes in Table 10-5.