National Instruments SCB-68A - Page 27

2-6 | ni.com
Chapter 2 Analog Input and Temperature Sensor Measurements
Table 2-2. Analog Input Configuration
AI Ground-
Reference
Setting
*
Floating Signal Sources
(Not Connected to
Building Ground)
Ground-Referenced
Signal Sources
*
Examples:
• Ungrounded thermocouples
• Signal conditioning with
isolated outputs
• Battery devices
Example:
• Plug-in instruments with
non-isolated outputs
Differential
(DIFF)
Non-Referenced
Single-Ended
(NRSE)
Referenced
Single-Ended
(RSE)
*
Refer to the documentation for your DAQ device for descriptions of the RSE, NRSE, and DIFF modes,
analog input signal sources, and software considerations.
+
–
+
–
AI+
AI–
AI GND
Signal Source DAQ Device
+
–
+
–
AI+
AI–
AI GND
Signal Source DAQ Device
+
–
+
–
AI
AI SENSE
AI GND
Signal Source DAQ Device
+
–
+
–
AI
AI SENSE
AI GND
Signal Source DAQ Device
+
–
+
–
AI
AI GND
Signal Source DAQ Device
Ground-loop potential (V
A
– V
B
) are added
to measured signal.
NOT RECOMMENDED
+
–
+
–
AI
AI GND
V
B
V
A
Signal Source DAQ Device