Chapter 4
Signal Connections
©
National Instruments Corporation
4-21
PCI-MIO E Series User Manual
Figure 4-7 shows how to connect a grounded signal source to a channel
on the PCI-MIO E Series board 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 PCI-MIO E
Series board. In these cases, the PGIA can reject any voltage caused by
ground potential differences between the signal source and the board. In
addition, with differential input connections, the PGIA can reject
common-mode noise pickup in the leads connecting the signal sources
to the board. The PGIA can reject common-mode signals as long as
V+
in
and V-
in
(input signals) are both within
±
11 V of AIGND. The
PCI-MIO-16XE-50 has the additional restriction that (V+
in
+ V-
in
)
added to the gain times (V+
in
- V-
in
) must be within
±
26 V of AIGND.
At gains of 10 and 100, this is roughly equivalent to restricting the two
input voltages to within
±
8 V of AIGND.
V
s
+
+
+
-
-
-
V
m
Measured
Voltage
ACH<0..15>
AIGND
Instrumentation
Amplifier
I/O Connector
AISENSE
V
cm
+
-
Selected Channel in NRSE Configuration
Common-
Mode
Noise
and Ground
Potential
Ground-
Referenced
Signal
Source
PGIA
Input Multiplexers
