National Instruments NI 9233 User Manual

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© National Instruments Corp.
9
NI 9233 Operating Instructions and Specifications
The NI 9233 analog input channels are referenced to the chassis 
ground through a 50
Ω resistor. To minimize ground noise, make 
sure that the chassis ground is connected to the earth ground. Each 
channel is protected from overvoltages. The NI 9233 provides 
an IEPE excitation current for each input signal. The signal is 
AC-coupled, buffered, and conditioned. The signal is then sampled 
by a 24-bit Delta-Sigma ADC. The NI 9233 IEPE excitation 
current and AC coupling are always enabled. Refer to Figure 4 for 
an illustration of the input circuitry for one channel of the NI 9233.
Figure 4.  Input Circuitry for One Channel of the NI 9233
NI 9233
AI+
AI–
50 
Ω
ADC
Amplifier
and
Prefilter
Excitation
Current
AC
Coupling
+