Chapter 2
Analog Input
©
National Instruments Corporation
2-21
Refer to the
Analog Input Terminal Configuration
section
for descriptions
of the input modes.
Table 2-6.
Recommended Input Configurations
Input
Signal Source Type
Floating Signal Sources
(Not Connect To Building
Ground)
Ground-Referenced Signal
Sources
Examples
• Ungrounded thermocouples
• Signal conditioning with
isolated outputs
• Battery devices
Examples
• Plug-in instruments
with non-isolated outputs
Differential (DIFF)
Single-Ended—
Ground Referenced
(RSE)
Single-Ended—
Non-Referenced
(NRSE)
+
–
+
–
Vs
AI –
AI GND
R
ext
AI +
+
–
+
–
V
s
AI +
AI –
AI GND
+
–
+
–
V
s
AI
AI GND
+
–
+
–
V
1
AI
+ V
g
–
AI GND
Ground-loop losses, Vg, are added
to measured signal.
NOT RECOMMENDED
+
–
+
–
V
s
AI
AI SENSE
AI GND
AI GND
R
ext
+
–
+
–
Vs
AI
AI SENSE
AI GND
