![background image](http://html1.mh-extra.com/html/keithley/das-1800hc-series/das-1800hc-series_user-manual_3961491035.webp)
Analog Input Features
2-15
Post-Trigger Acquisition
In post-trigger acquisition, the data of interest appears after a specific
event. Acquisition starts on an internal, analog, or digital trigger and
continues until a specified number of samples has been acquired or until
the operation is stopped by software.
Gates
A gate in the active state allows conversions to proceed. You can use
software to select a signal on the digital input DI1 pin (B40) of the main
I/O connector as a hardware gate.
The way conversions are synchronized depends on whether you are using
an internal or an external clock, as follows:
●
With internal clocking
— The 82C54 stops counting when the gate
signal goes inactive. When the gate signal goes active, the 82C54 is
reloaded with its initial count value and starts counting again;
therefore, with internal clocking, conversions are synchronized to the
gate signal.
●
With external clocking
— The signal from the external clock
continues uninterrupted while the gate signal is inactive; therefore,
with external clocking, conversions are synchronized to the external
clock.
Figure 2-5 illustrates the use of the hardware gate with both an external
clock and an internal clock. For information on the TGIN and TGOUT
signals, refer to “Digital I/O Features” on page 2-18.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com