2-4
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Chapter 2
Using the PXIe-4310
Figure 2-4 shows how to connect a high impedance, unbalanced source. A resistor,
R
balance
= R
source
, has been added between the signal ground and AI- to balance the output of the
source output impedance with respect to the signal ground.
Figure 2-4.
Signal Connection for a High Impedance Source
Working Voltage Range
The PGIA normally operates by amplifying signals of interest (V
SIG
) while rejecting
common-mode signals under the following three conditions:
•
The common-mode voltage (V
CM
), which is equivalent to subtracting COM <0..7> from
AI <0..7>-, must be less than ±11 V.
•
The signal voltage (V
SIG
), which is equivalent to subtracting AI <0..7>- from AI <0..7>+,
must be less than or equal to the range selection of the given channel. If V
SIG
is greater than
the range selected, the signal clips and information is lost.
•
The total working voltage of the positive input, which is equivalent to (V
CM
+ V
SIG
), or
subtracting COM <0..7> from AI <0..7>+, must be less than the maximum working voltage
specification. Refer to the
PXIe-4310 Specifications
working voltage limits
.
When using
the TB-4310 (600V), divide the input signal voltage (V
SIG
) by 60 when calculating the
working voltage, as shown in Figure 2-5.
I
s
ol
a
ted Gro
u
nd
Ch
ass
i
s
Gro
u
nd
+
–
AI+
AI–
COM
AI Ch
a
nnel
V
S
IG
+
–
V
I
S
O
R
b
a
l
a
nce
+
–
R
s
o
u
rce
S
ingle-Ended
S
o
u
rce
