User manual

Chapter 4 Connecting Signals
NI 6034E/6035E/6036E User Manual 4-16 ni.com
Single-Ended Connections for Floating Signal
Sources (RSE Configuration)
Figure 4-6 shows how to connect a floating signal source to a channel
configured for RSE mode on the NI 6034E/6035E/6036E device.
Figure 4-6. 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 your NI 6034E/6035E/6036E device in the NRSE input
configuration. The signal is then connected to the positive input of the
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
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 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
UM.book Page 16 Monday, May 14, 2001 10:32 AM