Single-Ended Connections For Floating Signal Sources (Rse Configuration); Single-Ended Connections For Grounded Signal Sources (Nrse Configuration) - National Instruments Data Acquisition Device E Series User Manual

Single-Ended Connections for Floating Signal Sources
(RSE Configuration)
Floating
V
Signal
s
Source
I/O Connector
Single-Ended Connections for Grounded Signal Sources
(NRSE Configuration)
© National Instruments Corporation
Figure 2-11 shows how to connect a floating signal source to a channel
configured for RSE mode.
AI
+
–
Input Multiplexers
AI SENSE
AIGND
Selected Channel in RSE Configuration
Figure 2-11. Single-Ended Connections for Floating Signal Sources
To measure a grounded signal source with a single-ended configuration,
you must configure your device in the NRSE input configuration. Connect
the signal to the positive input of the PGIA, and connect the signal local
ground reference to the negative input of the PGIA. The ground point of the
signal, therefore, connects to the AI SENSE pin, as shown in Figure 2-12.
Any potential difference between the device 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 a device were referenced to ground, as it is in the RSE input
configuration, this difference in ground potentials would appear as an error
in the measured voltage.
Programmable Gain
Instrumentation
Amplifier
+
PGIA
–
(RSE Configuration)
2-27
Chapter 2 Analog Input
+
Measured
V
m
Voltage
–
E Series User Manual