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Chapter 2 Function Reference — DAQ_Set_Clock
NI-DAQ FRM for PC Compatibles 2-134
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National Instruments Corporation
DAQ_Set_Clock
Format
DAQ_Set_Clock (deviceNumber, group, whichClock, desiredRate, units, actualRate)
Purpose
Sets the scan rate for a group of channels (DSA devices only).
Input
Output
Parameter Discussion
whichClock indicates the type of clock.
0: scan clock.
desiredRate is the rate at which you want data points to be sampled by the ADC(s).
units determines how desiredRate and actualRate are interpreted:
0: points per second.
1: seconds per point.
actualRate is the rate at which the ADCs produce samples. The capabilities of your device
will determine how closely actualRate matches desiredRate. The DSA devices use the same
base clock for both
DAQ/SCAN
and
WFM
operations so the rates available for a
DAQ/SCAN
will
be restricted if a
WFM
operation is already in progress.
Note
C programmers—actualRate is a pass-by-reference parameter.
Name Type Description
deviceNumber i16 assigned by configuration utility
whichClock u32 only scan clock supported
desiredRate f64 desired rate in units
units u32 ticks/second or seconds/tick
Name Type Description
actualRate f64 actual rate in units