Measurement Computing Data Translation DT3034, Руководство пользователя

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Principles of Operation
105
Figure 36: Example of Rate Generation Mode with a 25% Duty Cycle
One-Shot
Use one-shot mode to generate a single pulse output signal from the counter when the
operation is triggered (determined by the gate input signal). You can use this pulse output
signal as an external digital (TTL) trigger to start other operations, such as analog input or
analog output operations.
When the one-shot operation is triggered, a single pulse is output; then, the one-shot
operation stops. All subsequent clock input signals and gate input signals are ignored.
The period of the output pulse is determined by the clock input signal. In one-shot mode, the
internal C/T clock source is more useful than an external C/T clock source; refer to
page 96 for
more information on the internal C/T clock source.
Using software, specify the counter/timer mode as one-shot, the clock source as internal, the
polarity of the output pulse (high-to-low transition or low-to-high transition), and the gate
type to trigger the operation. Refer to
page 99 for more information on pulse output types and
to page 98 for more information on gate types.
Note: In the case of a one-shot operation, the pulse width is set to 100% automatically.
Ensure that the signals are wired appropriately. Figure 37 shows one example of connecting a
pulse output operation. This example uses the DT740 screw terminal panel and user counter 0.
Pulse
Output
Signal
25% duty cycle
Continuous Pulse
Output Operation Starts
External C/T
Clock
Input Signal
(4 kHz)