Sound and Vibration Data Acquisition
NI 9233, NI 9234
NEW!
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24-bit resolution
102 dB dynamic range
4 simultaneous analog inputs
±5 V input range
Antialiasing filters
TEDS read/write
Supported Hardware Platforms
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NI CompactDAQ
CompactRIO
Hi-Speed USB carrier
Wi-Fi/Ethernet carrier
Recommended Software
• LabVIEW
• Sound and Vibration Toolkit
• Sound and Vibration Measurement Suite
Model
NI 9233
NI 9234
Max Sampling Rate
50 kS/s
51.2 kS/s
IEPE
Always enabled (2 mA)
Software selectable
(0 or 2 mA)
Coupling
AC coupling
Software selectable
AC/DC coupling
Table 1. NI C Series Dynamic Signal Acquisition Selection Guide
Overview
NI 9233 and 9234 are 4-channel dynamic signal acquisition (DSA)
modules for making high-accuracy measurements from IEPE sensors.
These C Series analog input modules deliver 102 dB of dynamic range
and incorporate IEPE (2 mA constant current) signal conditioning for
accelerometers and microphones. The four input channels simultaneously
acquire at rates from 2 to 50 kHz or, with the NI 9234, up to 51.2 kS/s.
In addition, the modules include built-in antialiasing filters that
automatically adjust to your sampling rate. NI 9233/9234 modules
are ideal for a wide variety of mobile/portable applications such as
industrial machine condition monitoring and in-vehicle noise, vibration,
and harshness testing.
Hardware
Each simultaneous signal is buffered, analog
prefiltered, and sampled by a 24-bit delta-
sigma analog-to-digital converter (ADC) that
performs digital filtering with a cutoff
frequency that automatically adjusts to your
data rate. NI 9233/9234 modules feature a voltage range of ±5 V and a
dynamic range of more than 100 dB. In addition, the modules include the
Analysis Capabilities
Power spectra
Zoom FFTs
Fractional-octave analysis
Vibration level measurements
Order spectra
Transient analysis
capability to read and write to transducer electronic data sheet (TEDS)
Class 1 smart sensors. NI 9233/9234 modules provide ±30 V of overvoltage
protection (with respect to chassis ground) for IEPE sensor connections.
The NI 9234 has three software-selectable modes of measurement
operation: IEPE-on with AC coupling, IEPE-off with AC coupling, and
IEPE-off with DC coupling. IEPE excitation and AC coupling are not
software-selectable and are always enabled for the NI 9233.
NI 9233/9234 modules use a method of A/D conversion known as
delta-sigma modulation. If, for example, the data rate is 25 kS/s, then
each ADC actually samples its input signal at 3.2 MS/s (128 times the
data rate) and produces samples that are applied to a digital filter.
This filter then expands the data to 24 bits, rejects signal components
greater than 12.5 kHz (the Nyquist frequency), and digitally resamples
the data at the chosen data rate of 25 kS/s. This combination of analog
and digital filtering provides an accurate representation of desirable
signals while rejecting out-of-band signals. The built-in antialiasing
filters automatically adjust themselves to discriminate between signals
based on the frequency range, or bandwidth, of the signal.
NI [ NATIONAL INSTRUMENTS CORPORATION ]
