Counter Timing Engine - National Instruments DAQ X Series User Manual

Chapter 7 Counters
generations. The embedded counters cannot be programmed independent
of the main counter; signals from the embedded counters are not routable.

Counter Timing Engine

Unlike analog input, analog output, digital input, and digital output,
X Series counters do not have the ability to divide down a timebase to
produce an internal counter sample clock. For sample clocked operations,
an external signal must be provided to supply a clock source. The source
can be any of the following signals:
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Not all timed counter operations require a sample clock. For example, a
simple buffered pulse width measurement latches in data on each edge of a
pulse. For this measurement, the measured signal determines when data is
latched in. These operations are referred to as implicit timed operations.
However, many of the same measurements can be clocked at an interval
with a sample clock. These are referred to as sample clocked operations.
Table 7-1 shows the different options for the different measurements.
Note All hardware-timed single point (HWTSP) operations are sample clocked.
X Series User Manual
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AI Sample Clock
AI Start Trigger
AI Reference Trigger
AO Sample Clock
DI Sample Clock
DI Start Trigger
DO Sample Clock
CTR n Internal Output
Freq Out
PFI <0..15>
PXI_Trig <0..7>
PXIe-DSTAR<A,B>
Change Detection Event
Analog Comparison Event
7-2 ni.com