National Instruments PCI-6023E - Manual (Page 43)

Chapter 4 Signal Connections
PCI-6023E/6024E/6025E User Manual 4-14 © National Instruments Corporation
Differential Connections for Ground-Referenced
Signal Sources
Figure 4-5 shows how to connect a ground-referenced signal source to a
channel on the board configured in DIFF input mode.
Figure 4-5. Differential Input Connections for Ground-Referenced Signals
With this type of connection, the PGIA rejects both the common-mode
noise in the signal and the ground potential difference between the signal
source and the board ground, shown as V
cm
in Figure 4-5.
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
PCI.book Page 14 Wednesday, September 16, 1998 9:09 AM