© National Instruments
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3-21
Figure 3-21.
Pulse-Width Measurement: Implicit Timing
To use Implicit timing, use the DAQmx Timing (Implicit) VI or function.
Sample Clock
With Sample Clock timing, on each active edge of the sample clock, the device stores one
measurement. The one measurement is the pulse time of the most recent full pulse to occur
before the sample clock. Figure 3-22 shows an example of Sample Clock timing.
Figure 3-22.
Pulse-Width Measurement: Sample Clock
To use Sample Clock timing, use the DAQmx Timing (Sample Clock) VI or function.
Trigger Settings
By default, the counter begins measuring when software calls DAQmx Start Task. You can
change this behavior by setting DAQmx Trigger properties.
To have the counter begin counting in response to a hardware trigger, use an Arm Start Trigger.
1.
Set ArmStart.TrigType to Digital Edge.
2.
Set ArmStart.DigEdge.Src to select which signal to use as the ArmStartTrigger.
3.
Set ArmStart.DigEdge.Edge to select the rising or falling edge of the signal.
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