Chapter 4
Signal Connections
©
National Instruments Corporation
4-17
Figure 4-7 shows how to connect a grounded signal source to a channel
configured for NRSE mode.
Figure 4-7.
Single-Ended Input Connections for Ground-Referenced Signals
Common-Mode Signal Rejection Considerations
Figures 4-4 and 4-7 show connections for signal sources that are already
referenced to some ground point with respect to the device. In these cases,
the PGIA can reject any voltage caused by ground potential differences
between the signal source and the device. In addition, with differential
input connections, the PGIA can reject common-mode noise pickup in the
leads connecting the signal sources to the device. The PGIA can reject
common-mode signals as long as V+
in
and V–
in
(input signals) are both
within ±11 V of AIGND.
Ground-
Referenced
Signal
Source
Common-
Mode
Noise and
Ground
Potential
Input Multiplexers
AISENSE
Instrumentation
Amplifier
V
m
Measured
Voltage
AIGND
–
+
–
+
V
s
V
cm
+
–
–
+
I/O Connector
ACH+
ACH–
Selected Channel in DIFF Configuration
PGIA
Programmable Gain
