Common-Mode Signal Rejection Considerations; Figure 3-6. Single-Ended Input Connections For Grounded Signal Sources - National Instruments DAQ PCI-1200 User Manual

Chapter 3 Signal Connections
Ground-
+
Referenced
Signal
V
s
Source
–
Common-
Mode
Noise
V
cm
and so on
I/O Connector
PCI-1200 User Manual
RSE configuration, this difference in ground potentials appears as an error
in the measured voltage.
Figure 3-6 shows how to connect a grounded signal source to a PCI-1200
board configured in the NRSE configuration. Configuration instructions
are included in the
Installation and
1 ACH0
ACH1
2
ACH2
3
•
•
•
8 ACH7
9
+
AGND
11
–
PCI-1200 in NRSE Input Configuration

Figure 3-6. Single-Ended Input Connections for Grounded Signal Sources

Common-Mode Signal Rejection Considerations

Figures 3-4 and 3-6 show connections for signal sources that are already
referenced to some ground point with respect to the PCI-1200. In these
cases, the instrumentation amplifier can reject any voltage caused by
ground-potential differences between the signal source and the PCI-1200.
In addition, with differential input connections, the instrumentation
amplifier can reject common-mode noise pickup in the leads connecting the
signal sources to the PCI-1200.
The common-mode input range of the PCI-1200 instrumentation amplifier
is the magnitude of the greatest common-mode signal that can be rejected.
Analog I/O Configuration
Configuration.
•
•
•
AISENSE/AIGND
3-14
section in Chapter 2,
+
+
–
Measured
V
m
Voltage
–
© National Instruments Corporation