National Instruments AT E Series - Manual (Page 72)

Chapter 4 Connecting Signals
© National Instruments Corporation 4-25 AT E Series User Manual
Single-Ended Connections for Floating Signal
Sources (RSE Configuration)
Figure 4-8 shows how to connect a floating signal source to an AT E Series
device channel configured for RSE mode.
Figure 4-8. Single-Ended Input Connections for Nonreferenced or Floating Signals
Single-Ended Connections for Grounded Signal
Sources (NRSE Configuration)
To measure a grounded signal source with a single-ended configuration,
you must configure the AT E Series device in the NRSE input
configuration. The signal is then connected to the positive input of the
AT E Series PGIA, and the signal local ground reference is connected to
the negative input of the PGIA. The ground point of the signal should,
therefore, be connected to the AISENSE pin. Any potential difference
between the AT E Series ground and the signal ground appears as a
common-mode signal at both the positive and negative inputs of the PGIA,
and this difference is rejected by the amplifier. If the input circuitry of an
AT E Series device were referenced to ground, in this situation as in the
RSE input configuration, this difference in ground potentials would appear
as an error in the measured voltage.
Selected Channel in RSE Configuration
PGIA
Input Multiplexers
Programmable Gain
Instrumentation Amplifier
+
+
–
– AISENSE
AIGND
I/O Connector
+
–
V
s
ACH
V
m
Floating
Signal
Source
Measured
Voltage