Advantech PCI-1710 - Manual (Page 25)

Chapter 3 Signal Connections 21
card. With this connection, the PGIA rejects a common-mode voltage
V
cm
between the signal source and the PCI-1710/1710HG ground,
shown as V
cm
in Figure 3-3.
Figure 3-3: Differential input channel connection - ground reference signal source
If a floating signal source is connected to the differential input
channel, the signal source may exceed the common-mode signal range
of the PGIA, and the PGIA will be saturated with erroneous voltage-
readings. You must therefore reference the signal source to the
AIGND.
Figure 3-4 shows a differential channel connection between a floating
signal source and an input channel on the PCI-1710/1710HG card. In
this figure, each side of the floating signal source is connected
through a resistor to the AIGND. This connection can reject the
common-mode voltage between the signal source and the PCI-1710/
1710HG card ground.
External Internal