Differential Connections For Floating Signal Sources; Figure 3-3. Differential Input Connections For Grounded Signal Sources - National Instruments DAQCard-1200 User Manual

+
Grounded
Signal
V s
Source
–
Common-Mode
Noise,
+
Ground
Potential
V cm
–
Front I/O Connector
© National Instruments Corporation
ACH 0
1
ACH 2
3
ACH 4
5
ACH 6
7
ACH 1
2
ACH 3
4
ACH 5
6
ACH 7
8
AGND
11
DAQCard-1200 in DIFF Configuration

Figure 3-3. Differential Input Connections for Grounded Signal Sources

With this type of connection, the instrumentation amplifier rejects both the
common-mode noise in the signal and the ground-potential difference
between the signal source and the DAQCard-1200 ground, which is shown
as V in Figure 3-3.
cm

Differential Connections for Floating Signal Sources

Figure 3-4 shows how to connect a floating signal source to a
DAQCard-1200 that is configured for DIFF input. Configuration
instructions are included in the
Chapter 2, Installation and
+
–
Analog Input Configuration
Configuration.
3-9
Chapter 3 Signal Connections
+
Measured
V m
Voltage
–
section of
DAQCard-1200 User Manual