Chapter4 ConnectingSignals
NI6013/6014 User Man ual 4-12 ni.com
Differential Connections for Nonreferenced orFloating Signal Sources

Figure 4-5 shows how to connect a floating signal source to a channel

configured in DIFF input mode on the NI 6013/6014.

Figure4-5. DifferentialInput Connections for Nonreferenced Signals

Figure 4-5 showstwo bias resistors connected in parallel with the signal

leads of a floating signal source. If you do not use the resistors and the

source is truly floating, the source is unlikely to remain within the

common-modesignal range of the PGIA. The PGIA then saturates, causing

erroneous readings.

SelectedChannel in DIFF Configuration
PGIA
–
+
–
+
–
+
Floating
Signal
Source
Bias
Current
Return
Paths
Vs
Bias
Resistors
(seetext)
I/OConnector
AISENSE
AIGND
InputMultiplexers
Instrumentation
Amplifier
Measured
Voltage
Vm
ACH–
ACH+