Programming instructions

Chapter 5 Things You Should Know about Analog Input
LabVIEW Data Acquisition Basics Manual 5-12
© National Instruments Corporation
Figure 5-10 depicts an NRSE measurement system where AISENSE is the
common reference for taking measurements and AIGND is the system
ground. All signals must share a common reference at AISENSE.
Figure 5-10.
16-Channel NRSE Measurement System
In general, a differential measurement system is preferable because it
rejects not only ground loop-induced errors, but also the noise picked up in
the environment to a certain degree. On the other hand, the single-ended
configuration allows for twice as many measurement channels and is
acceptable when the magnitude of the induced errors is smaller than the
required accuracy of the data. You can use single-ended measurement
systems when all input signals meet the following criteria:
• High Level Signals (normally, greater than 1 V)
• Short or Properly-Shielded Cabling/Wiring Traveling through a
Noise-Free Environment (normally, less than 15 ft.)
• All Signals Can Share a Common Reference Signal at the Source
Use differential connections when your system violates any of the above
criteria.
+
+
CH0+
CH1+
CH2+
CH15+
MUX
Vm
Instrumentation Amplifier
AISENSE
AIGND
–
–