National Instruments NI660 Series, Руководство пользователя

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Chapter 3 Signal Connections
© National Instruments 3-11 NI 660x User Manual
Counter Source to Counter Out Delay
Fig u re 3-5 shows the Ctr n So u rce to Ctr n InternalO u tp u t delay.
Figure 3-5. CtrnSource to CtrnInternalOutput Delay
Fig u re 3-5 shows the delay between the active edge of the Ctr n So u rce
signal and the active edge of the Ctr n InternalO u tp u t signal. In the fig u re,
the Ctr n So u rce and Ctr n InternalO u tp u t signals are active high. If yo u u se
the p u lse o u tp u t mode for the Ctr n InternalO u tp u t signal, yo u will see the
TC p u lse one Ctr n So u rce period before the Ctr n InternalO u tp u t toggles
u nder the toggle o u tp u t mode.
The o u tp u t delay listed in Table 3-5 is for internal signals. The
corresponding delay val u es at a connector block are larger d u e to cable
delays.
Note When u sing d u plicate co u nt prevention mode, the minim u m period of signal u sed
as the so u rce of the co u nter m u st be greater than or eq u al to fo u r times the period of the
maxim u m timebase. For more information, refer to the Duplicate Count Prevention section
of this doc u ment.
Counter n Gate Signal
Yo u can select any PFI or RTSI, as well as many other internal signals like
the Co u nter n Gate (Ctr n Gate) signal. The Ctr n Gate signal is config u red in
edge-detection or level-detection mode depending on the application
performed by the co
u nter. The gate signal can perform many different
operations incl u ding starting and stopping the co u nter, generating
interr u pts, and saving the co u nter contents.
Table 3-5. Output Delay for Internal Signals
Parameter Typical Maximum Description
Tso 16 ns 26 ns Ctr n So u rce to Ctr n InternalO u tp u t delay
Ctr n InternalOutput
Tso Tso
Ctr n Source
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