The NI USB-4431 is a five-channel dynamic signal acquisition module delivering 24-bit resolution across four simultaneous analog input channels and one output channel. Purpose-built for sound and vibration measurements, it integrates software-selectable IEPE signal conditioning (0 or 2.1 mA) for direct accelerometer and microphone connectivity. Simultaneous sampling from 1 kS/s to 102.4 kS/s with 100 dB dynamic range and built-in anti-aliasing filters ensures high-fidelity data capture across a 0 Hz to 0.453× update rate measurement bandwidth. The single analog output channel operates to 96 kS/s and enables stimulus-response testing synchronized with input acquisition.
Technical Specifications
Analog Input
• 4 pseudodifferential channels, 24-bit resolution
• Sampling: 1 kS/s to 102.4 kS/s simultaneous
• Input range: ±10 V; dynamic range: 100 dB
• IEPE conditioning: software-selectable 0 or 2.1 mA
• AC/DC coupling with 0.8 Hz high-pass filter (AC mode)
• Overvoltage protection: ±60 V
• BNC connectors; 1 kΩ minimum load impedance
Analog Output
• 1 channel, 24-bit resolution
• Output range: ±3.5 V; update rate to 96 kS/s
• Frequency response: DC to 43.5 kHz
• 50 kΩ output impedance; indefinite short-circuit protection
Digital I/O
• TTL trigger support (5 V compatibility); ±5.6/−0.5 V input protection
Performance
• Delta-sigma ADC architecture with simultaneous sampling
• TEDS Class 1 read/write support for smart sensors
Physical & Environmental
• 142 × 180 × 38 mm; 675 g
• Operating/storage: −30 °C to 70 °C
• 10–80% RH non-condensing
• Power: 2.5 W maximum via USB 2.0
– Key Features
• Simultaneous four-channel acquisition with phase coherence
• Direct IEPE sensor excitation eliminates external conditioning
• Anti-aliasing filtering automatically tracks sample rate
• Overvoltage protection for field-deployed sensors
• TEDS compatibility for automatic sensor identification
– Typical Applications
• Machinery vibration monitoring and fault diagnostics
• Acoustic testing and noise characterization
• Transient and shock event capture
• Order tracking and rotational analysis
• Sound quality assessment
– Compatibility & Integration
• NI-DAQmx driver (v8.8+); Windows operating systems
• LabVIEW, Measurement Studio, LabWindows, MATLAB, Python, ANSI C, C#.NET support
• Built-in DSP: power spectra, zoom FFTs, fractional-octave analysis, order spectra
