Advantech PCIE-1802, User Manual

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17 PCIE-1802 User Manual
Chapter 3
S
ignal Connections
Figure 3.3 AI Differential Input Signal Connection
3.3.2.2 Pseudo-Differential Inputs
A pseudo-differential input is much like a differential input in that it provides common-
mode voltage rejection (unlike single-ended inputs). However, pseudo-differential
inputs are all referred, but not directly tied, to a common ground. This connection is
typically made by a relatively low value resistor to give some isolation between the
sensor/signal ground and the measurement device ground. DSA measurement
devices have a 50
Ω resistance between the negative signal connector the outer
shell of a BNC, and the device ground. A diagram showing the pseudo-differential
input configuration of the PCIE-1802 is shown below with a floating source.
Figure 3.4 AI Pseudo-Differential Input Signal Connection