Chapter 2
Using the SCXI-1530/1531
2-2
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Figure 2-1.
Typical Current-Excited Accelerometer
SCXI-1530/1530 Signal Conditioning
A block diagram of the SCXI-1530/1531 is shown in Figure 2-2. The
accelerometer is energized by the current source. You can disable the
current source to measure noise in the system. There is also a ground switch
that you can turn on or off in software to accommodate both
ground-referenced and non-referenced accelerometers. The incoming
signal is AC-coupled to a programmable-gain instrumentation amplifier.
This amplifier boosts the incoming signal by a gain of 1, 10, or 100. Next,
the signal passes through a programmable-bandwidth lowpass Bessel filter
for aliasing reduction. The simultaneous sample-and-hold circuitry then
assures that all channels are referenced to the same instant in time. Finally,
the conditioned signal is sent to the multiplexer circuitry and rear
connector.
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Piezoelectric Crystal
2
Seismic Mass
3
Charge-Sensitive Amplifier
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Signal Connector
5
Accelerometer Case
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2
3
4
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