The NI PXIe-4081 is a 7½-digit PXI Express digital multimeter and isolated digitizer that delivers high-resolution measurement and waveform acquisition in a single module. It provides dual functionality—precision DC/AC voltage and current measurements alongside time-domain data capture at up to 1.8 MS/s—enabling both static characterization and dynamic signal analysis in automated test systems.
Technical Specifications
DMM Resolution & Accuracy
• 7½ digits at 10 S/s; 5½ digits at 3 kS/s
• Flexible resolution: 10 to 26 bits
• DC voltage accuracy: 12 ppm of reading + 0.5 ppm of range (2-year guaranteed); 15 ppm achievable on 10 V range
• Temperature coefficient available with and without self-calibration
Voltage Measurement
• DC range: −1000 V to +1000 V
• AC range: up to 1000 V (700 V RMS)
• Input impedance: 10 MΩ ± 2% in parallel with 90 pF (typical)
• AC or DC coupling selectable
• Maximum volt-hertz product: 2.2 × 10⁷ V-Hz
• Maximum DC component: 400 V
• CMRR: >70 dB (DC to 60 Hz) typical with 1 kΩ resistance in LO lead
Current Measurement
• DC range: ±1 µA to ±3 A
• AC range: up to 3 A RMS
• External current shunt module (CSM) required for ranges beyond normal specification
Resistance Measurement
• Range: 10 µΩ to 5 GΩ
• 2-wire and 4-wire modes
• Accuracy specifications apply at apertures ≥100 ms with Offset Compensated Ohms (≤10 kΩ) or Auto Zero (≥100 kΩ)
• Offset nulling recommended for 2-wire; adds 200 mΩ to reading
Additional DMM Functions
• Frequency and period measurement
• Diode test capability
Isolated Digitizer
• Sampling rate: up to 1.8 MS/s
• Voltage ranges: ±100 mV to ±1000 V
• Current ranges: ±1 µA to ±3 A
• Waveform acquisition for voltage and current
Protection & Isolation
• Input protection: up to 1000 VDC or Vpk
• Current mode fuse: T 3.5 A 1000 V (time-lag); minimum interrupt rating 10 kA
• Measurement isolation: up to ±500 V
– Key Features
• Single-module integration of high-resolution DMM and waveform digitizer reduces channel count and footprint
• ±500 V isolation enables floating measurements on isolated signals
• High input impedance (10 MΩ) minimizes loading on high-impedance sources
• Flexible resolution from 10 to 26 bits optimizes measurement speed versus accuracy
– Typical Applications
• Automated characterization of power electronics and industrial components
• High-throughput battery and fuel cell testing
• Precision instrumentation validation
• Power conversion efficiency analysis requiring simultaneous voltage and current waveforms
– Compatibility & Integration
PXI Express module integrates into NI modular instrument platforms supporting multi-channel measurement expansion and synchronized data acquisition across mixed-signal test systems.
