National Instruments PCI-6110E/6111E - Manual (Page 44)

Chapter 4 Signal Connections
© National Instruments Corporation 4-11 PCI-6110E/6111E User Manual
Differential Connections for Ground-Referenced
Signal Sources
Figure 4-3 shows how to connect a ground-referenced signal source to
a channel on the 611X E board.
Figure 4-3. 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 611X E board ground, shown as V
cm
in Figure 4-3.
Differential Connections for Nonreferenced or
Floating Signal Sources
Figure 4-4 shows how to connect a floating signal source to a channel
on the 611X E board.
Ground-
Referenced
Signal
Source
Common-
Mode
Noise and
Ground
Potential
Instrumentation
Amplifier
V
m
Measured
Voltage
ACH0GND
-
+
-
+
V
s
V
cm
+
-
-
+
I/O Connector
ACH0+
ACH0-
ACH0 Connections Shown
PGIA
PCI_E.book Page 11 Thursday, June 25, 1998 12:55 PM