Chapter 4
Analog Input
©
National Instruments
4-43
X Series User Manual
Choose an inp
u
t range that matches the expected inp
u
t range of yo
u
r signal.
A large inp
u
t range can accommodate a large signal variation, b
u
t red
u
ces
the voltage resol
u
tion. Choosing a smaller inp
u
t range improves the voltage
resol
u
tion, b
u
t may res
u
lt in the inp
u
t signal going o
u
t of range.
For more information abo
u
t setting ranges, refer to the
NI-DAQmx Help
or
the
LabVIEW Help
.
Table 4-5 shows the inp
u
t ranges and resol
u
tions s
u
pported by the
Sim
u
ltaneo
u
s MIO X Series device family.
Working Voltage Range
On most Sim
u
ltaneo
u
s MIO X Series devices, the PGIA operates normally
by amplifying signals of interest while rejecting common-mode signals
u
nder the following three conditions:
•
The common-mode voltage (V
cm
), which is eq
u
ivalent to s
u
btracting
AI <0..
x
> GND from AI <0..
x
>–, m
u
st be less than ±10 V. This V
cm
is
a constant for all range selections.
•
The signal voltage (V
s
), which is eq
u
ivalent to s
u
btracting AI <0..
x
>+
from AI <0..
x
>–, m
u
st be less than or eq
u
al to the range selection of
the given channel. If V
s
is greater than the range selected, the signal
clips and information are lost.
•
The total working voltage of the positive inp
u
t, which is eq
u
ivalent to
(V
cm
+ V
s
), or s
u
btracting AI <0..
x
> GND from AI <0..
x
>+, m
u
st be
less than ±11 V.
If any of these conditions are exceeded, the inp
u
t voltage is clamped
u
ntil
the fa
u
lt condition is removed.
Table 4-5.
Simultaneous MIO X Series Device Input Range and Nominal Resolution
Simultaneous MIO
X Series Device
Input Range
Nominal Resolution Assuming
5% Over Range
NI 6356/6358/6366/6368
–10 V to 10 V
320
μ
V
–5 V to 5 V
160
μ
V
–2 V to 2 V
64
μ
V
–1 V to 1 V
32
μ
V
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