Справочник Пользователя для National Instruments NI PCI-6110
Chapter 4
Connecting Signals
4-24
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If you are performing an internally timed acquisition, NI-DAQ generates
three extra points to clock the data for you. However, if you perform an
externally clocked acquisition, NI-DAQ does not know when the last point
is taken, so you must provide the three extra pulses.
three extra points to clock the data for you. However, if you perform an
externally clocked acquisition, NI-DAQ does not know when the last point
is taken, so you must provide the three extra pulses.
CONVERT* Signal
Any PFI pin can receive as an input the CONVERT* signal, which is
available as an output on the PFI2/CONVERT* pin.
available as an output on the PFI2/CONVERT* pin.
As an input, CONVERT* is configured in the edge-detection mode.
You can select any PFI pin as the source for CONVERT* and configure
the polarity selection for either rising or falling edge. The selected edge
of CONVERT* initiates an A/D conversion.
You can select any PFI pin as the source for CONVERT* and configure
the polarity selection for either rising or falling edge. The selected edge
of CONVERT* initiates an A/D conversion.
As an output, CONVERT* reflects the actual convert pulse that is
connected to the ADC, even if another PFI is externally generating the
conversions. The output is an active low pulse with a pulse width of 50 to
100 ns. This output is set to high-impedance at startup.
connected to the ADC, even if another PFI is externally generating the
conversions. The output is an active low pulse with a pulse width of 50 to
100 ns. This output is set to high-impedance at startup.
Figures 4-17 and 4-18 show the timing requirements for CONVERT*.
Figure 4-17. CONVERT* Input Signal Timing
Rising-Edge
Polarity
Falling-Edge
Polarity
t
w
= 10 ns minimum
t
w