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Chapter 4
Analog Input
©
National Instruments
4-27
X Series User Manual
If an AI Reference Trigger (ai/ReferenceTrigger) p
u
lse occ
u
rs before the
specified n
u
mber of pretrigger samples are acq
u
ired, the trigger p
u
lse is
ignored. Otherwise, when the AI Reference Trigger p
u
lse occ
u
rs, the
sample co
u
nter val
u
e decrements
u
ntil the specified n
u
mber of posttrigger
samples have been acq
u
ired.
MIO X Series devices feat
u
re the following analog inp
u
t timing signals:
•
AI Sample Clock Signal
*
•
AI Sample Clock Timebase Signal
•
AI Convert Clock Signal
*
•
AI Convert Clock Timebase Signal
•
AI Hold Complete Event Signal
•
AI Start Trigger Signal
*
•
AI Reference Trigger Signal
*
•
AI Pause Trigger Signal
*
Signals with an
*
s
u
pport digital filtering. Refer to the
PFI Filters
section
of Chapter 8,
PFI
, for more information.
Aggregate versus Single Channel Sample Rates
MIO X Series devices are characterized with maxim
u
m single channel and
maxim
u
m aggregate sample rates. The maxim
u
m single channel rate is the
fastest yo
u
can acq
u
ire data on the device from a single channel and still
achieve acc
u
rate res
u
lts. The maxim
u
m aggregate sample rate is the fastest
yo
u
can acq
u
ire on m
u
ltiple channels and still achieve acc
u
rate res
u
lts. For
example, NI 6351 devices have a single channel maxim
u
m rate of
1.25 MS/s and aggregate maxim
u
m sample rate of 1 MS/s so they can
sample one channel at 1.25 MS/s or two channels at 500 kS/s per channel,
as shown in Table 4-4.
Table 4-4.
Analog Input Rates for MIO X Series Devices
MIO X Series Device
Analog Input Rate
Single Channel
Multi-Channel
(Aggregate)
NI 632
x
250 kS/s
250 kS/s
NI 634
x
500 kS/s
500 kS/s
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