NI USB-4431 Five-Channel Dynamic Signal Acquisition Module

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

• 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