Chapter 4
Analog Input
X Series User Manual
4-6
ni.com
AI gro
u
nd-reference setting is sometimes referred to as AI terminal
config
u
ration.
Configuring AI Ground-Reference Settings in
Software
Yo
u
can program channels on an MIO X Series device to acq
u
ire with
different gro
u
nd references.
To enable m
u
ltimode scanning in LabVIEW,
u
se
NI-DAQmx Create
Virtual Channel.vi
of the NI-DAQmx API. Yo
u
m
u
st
u
se a new VI for
each channel or gro
u
p of channels config
u
red in a different inp
u
t mode. In
Fig
u
re 4-3, channel 0 is config
u
red in differential mode, and channel 1 is
config
u
red in RSE mode.
Figure 4-3.
Enabling Multimode Scanning in LabVIEW
To config
u
re the inp
u
t mode of yo
u
r voltage meas
u
rement
u
sing the DAQ
Assistant,
u
se the
Terminal Configuration
drop-down list. Refer to the
DAQ Assistant Help
for more information abo
u
t the DAQ Assistant.
To config
u
re the inp
u
t mode of yo
u
r voltage meas
u
rement
u
sing the
NI-DAQmx C API, set the
terminalConfig
property. Refer to the
NI-DAQmx C Reference Help
for more information.
Multichannel Scanning Considerations
MIO X Series devices can scan m
u
ltiple channels at high rates and digitize
the signals acc
u
rately. However, yo
u
sho
u
ld consider several iss
u
es when
designing yo
u
r meas
u
rement system to ens
u
re the high acc
u
racy of yo
u
r
meas
u
rements.
In m
u
ltichannel scanning applications, acc
u
racy is affected by settling
time. When yo
u
r MIO X Series device switches from one AI channel to
another AI channel, the device config
u
res the NI-PGIA with the inp
u
t range
of the new channel. The NI-PGIA then amplifies the inp
u
t signal with the
gain for the new inp
u
t range. Settling time refers to the time it takes the
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