Data Translation DT9820 Series, User Manual

Page: 62 / 112

Chapter 4
50
Set Clocks and Triggers
This trigger source starts acquisition. Specify
OL_TRG_SOFT (the default) for the software
trigger, OL_TRG_EXTERN for the external digital
trigger, or OL_TRG_DIGITALEVENT for the digital
event trigger.
A high-to-low transition on digital input 0 starts A/D
subsystem 0, a high-to-low transition on digital
input 1 starts A/D subsystem 1, a high-to-low
transition on digital input 2 starts A/D subsystem 2,
and a high-to-low transition on digital input 3 starts
A/D subsystem 3.
If you specified the trigger source as
OL_TRG_EXTERN, a high-to-low transition on
digital input 4 pauses A/D subsystem 0, a
high-to-low transition on digital input 5 pauses A/D
subsystem 1, a high-to-low transition on digital
input 6 pauses A/D subsystem 2, and a high-to-low
transition on digital input 7 pauses A/D subsystem
3.
If you specified the trigger source as
OL_TRG_DIGITALEVENT, a high-to-low transition
on digital input 4 stops A/D subsystem 0, a
high-to-low transition on digital input 5 stops A/D
subsystem 1, a high-to-low transition on digital
input 6 stops A/D subsystem 2, and a high-to-low
transition on digital input 7 stops A/D subsystem 3.
Refer to
page 14 for more information.
Specify the clock source as
OL_CLK_INTERNAL using
olDaSetClockSource.
Specify the frequency of the
internal A/D sample clock using
olDaSetClockFrequency.
The minimum frequency is 7.5 Hz for 60 Hz
operation and 6.25 Hz for 50Hz operation. The
maximum frequency is 960 S/s for 60 Hz operation
and 800 S/s for 50 Hz operation. The driver sets the
actual frequency as closely as possible to the
number specified.
Specify the trigger source
using olDaSetTrigger.