JYTEK NuDAQ PCI-69222, User Manual

Page: 32 / 80

22 Hardware Information
Non-Referenced Single-Ended (NRSE) Mode
To measure ground-referenced signal sources, which are con -
nected to the same ground point, you can connect the signals
in NRSE mode. Figure 2-3 illustrates the connection. The signal’s local
ground reference is connected to the negative input of the instru -
mentation amplifier (AISENSE pin on CN1 connector), and the com -
mon-mode ground potential between signal ground and the
onboard ground will be rejected by the instrumentation amplifier.
Figure 2-3: Ground-referenced Sources and NRSE Input Connections
Differential input mode
The differential input mode provides two inputs that respond to
signal voltage difference between them. If the signal source is
ground-referenced, the differential mode can be used for the
common-mode noise rejection. Figure 2-4 shows the connection of
ground-referenced signal sources under differential input mode.
Figure 2-4: Ground-referenced Source and Differential Input
x
AIn
AISENSE
n = 0, ...,63
Ground-
Referenced
Signal Source
Instrumentation
Amplifier
To A/D
Converter
Input Multipexer
V1 V2
+
-
+
-
V
cm
Common-
mode noise &
Ground
potential
x
AIxH
AIxL
x = 0, ..., 31
Ground
Referenced
Signal
Source
To A/D
Converter
AIGND
+
-
Instrumentation
Amplifier
V
cm
Common-
mode noise &
Ground
potential
+
-
Input Multipexer