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Chapter 2 Function Reference — DAQ_Rate
NI-DAQ FRM for PC Compatibles 2-132
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National Instruments Corporation
DAQ_Rate
Format
status = DAQ_Rate (rate, units, timebase, sampleInterval)
Purpose
Converts a DAQ rate into the timebase and sample-interval values needed to produce the rate
you want.
Parameters
Input
Output
Parameter Discussion
rate is the DAQ rate you want. The units in which rate is expressed are either points per
second (pts/s) or seconds per point (s/pt), depending on the value of the units parameter.
Range: Roughly 0.00153 pts/s through 5,000,000 pts/s or 655 s/pt through 0.000001 s/pt.
units indicates the units used to express rate.
0: pts/s.
1: s/pt.
timebase is a code representing the resolution of the onboard clock signal that the device uses
to produce the acquisition rate you want. You can input the value returned by timebase
directly to
DAQ_Start, Lab_ISCAN_Start, or SCAN_Start. timebase has the following
possible values.
–3: 20 MHz clock used as the timebase (50 ns) (E Series only).
–1: 200 ns (AT-MIO-16F-5, AT-MIO-64F-5, AT-MIO-16X and E Series devices
only).
Name Type Description
rate f64 desired DAQ rate
units i16 pts/s or s/pt (see CTR_Rate)
Name Type Description
timebase i16 onboard source signal used
sampleInterval u16 number of timebase units that elapse between
consecutive A/D conversions