© National Instruments Corp. 15 FP-CTR-502 and cFP-CTR-502
To determine the frequency of the output from the pulse counter,
use the following formula:
where fpulse is the pulse counter output frequency
fpre is the prescaler counter output frequency
termpulse is the terminal count value for the pulse counter
Step 3. Configure the Pulse Train Output Channel
To configure the pulse train output channel, complete the following
steps:
1. For the output channel that you selected, set the Output Source
to the pulse-counter channel.
2. Set the Output Mode of the output channel. To generate a pulse
train with variable duty cycle, use one of the pulse modes—On
Pulse or Off Pulse. To generate a 50% duty-cycle pulse train,
use one of the toggle modes.
To determine the duty cycle, use the following formulas:
For On Pulse mode, use
For Off Pulse mode, use
where d is the duty cycle of the pulse train
termpulse is the terminal count value of the pulse counter
When you set the output to one of the pulse modes, the frequency
of the pulse train (fpulse) is the same as that shown in Step 2. Set Up
the Pulse Counter , but the output frequency is half that value when
you set the output channel to one of the toggle modes.
f
pulse
fpre
termpulse 1+
--------------------------------=
d1
termpulse 1+
-------------------------------- =
d11
termpulse 1+
--------------------------------


–=