National Instruments NI660 Series, Руководство пользователя

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Chapter 3 Signal Connections
© National Instruments 3-13 NI 660x User Manual
Fig u re 3-7 shows the timing req u irements for the Ctr n A u x signal.
Figure 3-7. Timing Requirements for the CtrnAux Signal
Counter n Internal Output Signal
The Co u nter n Internal O u tp u t (Ctr n InternalO u tp u t) signal is available only
as an o u tp u t on the CTR n OUT pin, where n is the n u mber of yo u r co u nter.
For example, the Ctr0InternalO u tp u t signal is available as an o u tp u t on the
PFI 36/CTR 0 OUT pin. Yo u can also ro u te the Ctr n InternalO u tp u t signal
to other locations on the board, s u ch as RTSI.
The Ctr n InternalO u tp u t signal reflects the terminal co u nter (TC) of
co u nter n . The co u nter generates a terminal co u nt when its co u nt val u e
rolls over. The two software-selectable o u tp u t options are p u lse on TC and
toggle o u tp u t polarity on TC. The o u tp u t polarity is software-selectable
for both options. This o u tp u t is set to high-impedance at start u p.
Hardware Arm Start Triggers
Yo u can arm each co u nter u sing a software command or by u sing the
Arm Start Trigger. The Arm Start Trigger may be an internal or an external
signal. By
u sing the Arm Start Trigger, yo u can start more than one co u nter
sim u ltaneo u sly by config u ring each co u nter to u se the same Arm Start
Trigger signal.
Table 3-7. Minimum Pulse Width for Ctr n Aux Internal Signals
Parameter Minimum
Minimum
with RTSI
Connector Description
Ta u xpw 5 ns 5 ns Ctr n A u x minim u m p u lse width
Ctr n Aux
Tauxpw
Tauxpw
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