II. Model Interpretation

PXI: 3U PXI standard bus, single slot, compatible with PXI/PXIe mixed chassis.

4461: NI Dynamic Signal Acquisition (DSA) series code, representing 2 input 2 output, 24-bit, high dynamic range, IEPE, audio/vibration dedicated.

779687‑01: Standard model, including 2 analog inputs + 2 analog outputs + IEPE conditioning.

Location: Mid-to-high-end audio/vibration DSA, integrated excitation and acquisition, suitable for closed-loop testing, frequency response, noise vibration analysis.

III. Technical Parameters (25 ℃, preheating 30 min)

(1) Channel Configuration

Channel Type Resolution Sampling / Update Rate Dynamic Range

AI0~AI1 Analog Input (differential) 24-bit Σ‑Δ ADC Up to 204.8 kS/s 118 dB

AO0~AO1 Analog Output (differential) 24-bit Σ‑Δ DAC Up to 204.8 kS/s 118 dB

(2) Input Characteristics (AI)

Voltage Range: ±316 mV, ±1 V, ±3.16 V, ±10 V, ±31.6 V, ±42.4 V (6 levels).

Gain: -20, -10, 0, +10, +20, +30 dB (software selectable).

Coupling: AC/DC (per channel independently).

IEPE Conditioning: 0/4/10 mA constant current excitation, 24 V compliance, supports accelerometers/microphones.

Input Resistance: 1 MΩ || 240 pF (IEPE on); 100 kΩ (voltage mode).

No Aliasing Bandwidth: 92 kHz (204.8 kS/s).

THD+N: ≤‑100 dB (1 kHz, full scale).

(3) Output Characteristics (AO)

Voltage Range: ±1 V, ±3.16 V, ±10 V (4 levels).

Update Rate: 1 kS/s~204.8 kS/s (synchronous).

Output Resistance: 50 Ω (pseudo-differential).

No Mirror Bandwidth: 92 kHz.

THD+N: ≤‑95 dB (1 kHz, full scale).

(4) Electrical / Mechanical / Environmental

Power Supply: PXI backplane + 5 V/+12 V, maximum 12 W.

Connectors: 4×BNC (AI0/AI1/AO0/AO1).

Size / Weight: 3U single slot (216×20×130 mm); approximately 310 g.

Safety: IEC 61010‑1, CAT I 30 V.

Temperature: Operating 0 ℃~55 ℃; accuracy guaranteed 15 ℃~35 ℃.

Calibration Cycle: 1 year (NIST traceable).

IV. Interface and Communication Configuration

(1) Front-End I/O (BNC)

AI0/AI1: Differential analog input, supports IEPE/voltage input.

AO0/AO1: Differential analog output, used for excitation signal generation.

Trigger In/Out: PXI trigger synchronization, multi-module synchronous delay ≤ 1 μs.

(2) Status Indicator Lights (Panel)

PWR: Green = Normal power supply.

RUN: Green = Acquisition/output running; flashing = Trigger waiting.

ERR: Red = Fault (over-temperature / over-current / calibration error).

(3) Bus and Software

Bus: Standard PXI, compatible with PXIe, supports PXI Trigger/PFI synchronization. Driver: NI-DAQmx, compatible with LabVIEW/TestStand/Python/C#.

Configuration: NI MAX (identification, self-check, parameter configuration, calibration, triggering).

Software tools: Sound and Vibration Toolkit, Order Analysis Toolkit.

VII. Core Functions

2 Input 2 Output Synchronous Acquisition and Excitation: Closed-loop testing (such as vibration table control, speaker frequency response), synchronous delay < 1 μs.

118 dB Ultra High Dynamic Range: Simultaneous measurement of weak and strong signals, suitable for microphone/accelerometer wide range requirements.

Integrated IEPE Sensor Conditioning: 0/4/10 mA constant current, direct drive for IEPE accelerometers/microphones, simplifies wiring.

24-bit High Precision Σ-Δ Conversion: Low noise, low distortion, suitable for audio, vibration, acoustic precision testing.

Programmable Anti-aliasing / Anti-Reflection Filtering: Independent per channel, suppresses high-frequency interference, ensures measurement accuracy.

AC/DC Coupling + 6 Gain Levels: Suitable for DC (such as sensor bias) and AC (such as audio/vibration) signals.

Multi-module Synchronization: Up to 17 modules synchronized in a single chassis, supports multi-channel NVH/acoustic array testing.

TEDS Sensor Plug-and-Play: Automatically reads sensor electronic data sheet, automatically configures sensitivity/calibration.

VIII. Application Scenarios

Audio Testing: Speaker/earphone frequency response, distortion, signal-to-noise ratio; microphone calibration and sensitivity testing.

Automotive NVH: Vehicle/vehicle component noise, vibration, sound vibration roughness analysis; engine/transmission vibration monitoring.

Vibration and Structural Testing: Modal analysis, impact response, resonance point identification; rotating machinery condition monitoring (bearing/gear faults).

Acoustic Measurement: Environmental noise, sound pressure level, sound power; building/material sound insulation/acoustic testing.

Industrial Automation: Equipment health monitoring, fault diagnosis, predictive maintenance; production line vibration/noise quality control.

Research and Education: Precise measurement in acoustic/vibration laboratories; university dynamic signal analysis teaching experiments.

IX. Usage and Maintenance Instructions

(1) Installation and Power On

Installation: Disconnect power, insert PXI single slot, tighten panel screws; chassis properly grounded.

Preheating: Power on for 30 minutes to ensure 24-bit accuracy; NI MAX self-checks without errors.

Heat Dissipation: Normal fan operation, environmental temperature ≤ 55 ℃, no obstruction to ventilation openings.

(2) Wiring and Operation

BNC Wiring: Use 50 Ω coaxial cable for AI/AO, single-ended grounding of the shield layer to reduce interference.

IEPE Sensor: Enable IEPE (4 mA commonly used) for AI channels; do not connect ordinary voltage signals.

Coupling Selection: Use AC coupling for AC signals (audio/vibration); use DC coupling for DC/low-frequency signals.

Gain Setting: Signal amplitude close to full scale (≥ 80%), maximizes signal-to-noise ratio.

Synchronous Trigger: Use PXI Trigger for multi-module testing to ensure time synchronization.

(3) Maintenance and Calibration

Regular Calibration: Once per year external NIST traceable calibration; daily internal self-calibration to compensate for temperature drift.

Cleaning and Maintenance: Regularly clean BNC terminals of dust, keep dry; disconnect power for long-term storage to prevent dust, cover terminals for protection.

Environmental Control: Working environment 0 ℃~55 ℃, no condensation, humidity 5%~95% RH, away from strong vibration/strong electromagnetic interference.

Prohibition of Use: Do not allow overpressure (> ± 50 V) input; Avoid electrostatically charged BNC connections; the IEPE channel must not be connected to devices with high sensitivity to static electricity.