National Instruments PCI-8254R Manuale Utente Scaricare il pdf (Pagina 18)

Chapter 2 Hardware Overview

Pulse Width

Pulse width is the amount of time between the first (assertion) edge of a

pulse and the second (deassertion) edge. Pulse width is configurable only

in microseconds from 1 µs to 4,294,967,295 µs.

Trigger Polarity

Each pulse generator can be individually configured for rising or falling

edge triggering. Even if multiple pulse generators are using the same

trigger, each can have different polarities.

Figure 2-2 shows the output of a pulse generator configured to look for a

rising edge trigger and output a high pulse with a microsecond width and

delay.

Figure 2-2. Output pulse generator

Figure 2-3 shows how to create a high and low pulse train with a

microsecond delay and width.

Figure 2-3. High and low pulse train

Trigger

Pulse

Delay Width

Low Pulse Train

High Pulse Train

Delay Width

WidthDelay

Software

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National Instruments PCI-8254R Manuale Utente Pagina 18