II. Model Interpretation

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

4071: The serial number of NI's high-end FlexDMM series, representing a 7½-bit, ±1000 V, 1.8 MS/s isolated digital instrument.

Full name: PXI-4071 7½-bit FlexDMM (with high-voltage isolated digital instrument).

Position: 7½-bit precision DMM + high-speed isolated digital instrument integrated, replacing bench 7½-bit meters + independent high-voltage oscilloscope, targeting top precision and high-voltage testing requirements.

III. Technical Parameters (25℃ ± 1℃, calibration cycle 2 years, preheating 1 hour)

(1) DMM Mode Measurement Function

DC Voltage (DCV)

Range: 100 mV / 1 V / 10 V / 100 V / 1000 V

2-year accuracy: 7 ppm reading + 0.5 ppm (10 V range)

Temperature coefficient: 0.1 ppm/℃ + 0.01 μV/℃

AC Voltage (True RMS ACV)

Range: 100 mV / 1 V / 10 V / 100 V / 1000 V

Bandwidth: 10 Hz～100 kHz

Accuracy: 0.01% reading + 20 μV (10 V range, 1 kHz)

DC Current (DCI)

Range: 10 mA / 100 mA / 1 A / 3 A

Accuracy: 0.02% reading + 10 nA (1 A range)

AC Current (True RMS ACI)

Range: 10 mA / 100 mA / 1 A / 3 A

Bandwidth: 10 Hz～100 kHz

Accuracy: 0.05% reading + 100 nA (1 A range, 1 kHz)

Resistance (Ω)

Mode: 2-wire / 4-wire

2-wire range: 100 Ω～5 GΩ

4-wire range: 100 Ω～1 MΩ

Accuracy: 0.005% reading + 5 mΩ (1 kΩ range, 4-wire)

Frequency / Period: 10 Hz～100 kHz, accuracy 0.005%

Diode Testing: 3.5 V@1 mA

Resolution: 7½-bit (26 bit), software can be reduced to 6½/5½/4½-bit NI

Reading Rate: 7½-bit approximately 7 times/second; 6½-bit 100 times/second; 3½-bit up to 3,000 times/second NI

(2) Digital Instrument Mode (Core Advantages)

Sampling Rate: Up to 1.8 MS/s (single channel)

Resolution: 10～26 bit adjustable (adapted dynamically to sampling rate) NI

Input Range: ±10 V / ±100 V / ±1000 V (isolated)

Bandwidth: DC～500 kHz

Isolation Voltage: 1000 Vrms (channel - ground isolation)

Trigger: Edge / Window / Pulse Width / Digital Trigger, delay as low as 2 μs

(3) Electrical and Physical Characteristics

Power Supply: PXI backplane 12 V/5 V/3.3 V; typical 6.9 W, maximum 8 W NI

Connectors: Front end 5 safety banana sockets (HI, LO, HI Sense, LO Sense, ground) + 1 9-pin DIN trigger / auxiliary I/O port NI

Size: 3U PXI single slot, 2.0 cm × 13.0 cm × 21.6 cm NI Weight: Approximately 314 g NI

Safety Class: IEC 61010-1, UL 61010-1, CSA 61010-1 (CAT III)

(4) Environmental Parameters

Operating Temperature: 0 ℃ - 40 ℃ (accuracy guaranteed within 15 ℃ - 35 ℃)

Storage Temperature: -40 ℃ - 70 ℃

Humidity: 10% - 90% (operation), 5% - 95% (storage), no condensation

Preheating Time: 1 hour (ensuring 7½ digit accuracy)

Calibration Period: 2 years (NIST traceable)

4. Interface and Communication Configuration

(1) Front-end I/O Interface

5 × Safety Banana Socket (gold-plated low-thermal-electric copper material, low leakage insulation) NI

HI: Positive Voltage / Resistance Terminal

LO: Common Negative Terminal

HI Sense: 4-wire Resistance Positive Sensing Terminal

LO Sense: 4-wire Resistance Negative Sensing Terminal

Ground: Shielded Ground (isolated from the digital instrument ground)

9-pin DIN Interface (AUX I/O): Trigger Input / Output, PXI Trigger Synchronization, SCXI Communication NI

(2) Bus and Software Communication

Bus Interface: Standard PXI Bus, compatible with PXI/PXIe Hybrid Slot

Driver: NI-DMM (IVI compliant) + NI-Digitizer

Software Support: LabVIEW, TestStand, LabWindows/CVI, Python, C/C++, .NET

Configuration Tool: NI MAX (Hardware Identification, Self-Calibration, Trigger Configuration, Channel Testing)

Trigger Function: PXI Trigger, PFI, Software Trigger; Multi-module Synchronization, Delay ≤ 2 μs

Calibration: Internal Self-Calibration (real-time compensation for temperature drift) + External Calibration (2-year cycle)

5. Core Functions

7½-digit Ultra-High Precision: DC Voltage Accuracy up to ppm level, Built-in LTZ1000 Super Voltage Reference, suitable for metrology calibration, precise sensor testing.

±1000 V High Voltage Measurement: Both DMM and Digitalizer support 1000 V high voltage, isolated 1000 Vrms, safe measurement of high-voltage floating ground signals.

1.8 MS/s Isolated Digitalizer: High-speed waveform capture, measurement of high-voltage transients, power supply ripples, switching noise, replacing independent high-voltage oscilloscope.

4-wire Resistance Precise Measurement: Eliminates lead resistance, suitable for low-resistance precise resistors, RTD (platinum resistors), with accuracy up to 0.005%.

True RMS AC Measurement: Accurate measurement of non-sinusoidal waveforms (frequency converters, switch power supplies output), no average value error.

Flexible Resolution (10 - 26 bit): Sampling rate and resolution dynamically balanced,兼顾 high-speed and ultra-high precision NI.

Multi-instrument Integration： 7½-digit DMM + High-Voltage Isolated Digitalizer， single slot position replaces "Desktop 7½-digit Meter + High-Voltage Oscilloscope + Data Acquisition Card"， simplifies the system and reduces costs.

Low Drift Design： Built-in temperature compensation， maintains ultra-high precision in the entire temperature range (0 - 40 ℃)， long-term stability excellent.

6. Application Scenarios

Metrology Calibration Laboratory： As a transfer standard， calibrate 6½-digit and below DMM， power supplies， multimeters， etc.

High Voltage Power Supply Testing： 1000 V level switching power supplies， high-voltage DC sources， high-precision parameters + ripple testing of lithium battery management systems.

Semiconductor Device Development： Static parameters of MOSFET， IGBT， high-voltage diodes + dynamic switch waveform measurement.

Precise Sensor Calibration： Ultra-high precision resistance / voltage measurement for RTD， thermocouples， pressure sensors + dynamic response waveform acquisition. Automated Test System (ATE): Batch ultra-high-precision testing for medical equipment, avionics, and communication modules, covering both static parameters and dynamic waveforms.

Maintenance of industrial high-voltage equipment: Precise on-site measurement of high-voltage motors, frequency converters, and transformers + waveform diagnosis.

VII. Usage and Maintenance Instructions

(1) Installation and Power On

Before installation, turn off the power supply, insert the PXI chassis into a single slot, and tighten the panel screws.

After powering on, allow it to preheat for 1 hour to ensure 7½-digit accuracy (reducing temperature drift).

Confirm the equipment is normal and error-free in NI MAX, complete the driver installation and self-check.

(2) Wiring and Operation

High Voltage Safety: When measuring ≥ 100 V, use a safety banana plug to avoid electric shock; do not exceed 1000 V input.

4-wire resistance connection: HI Sense, LO Sense (sensing wires) are connected separately from HI, LO (current wires) to eliminate lead errors.

Digital Instrument Mode: When measuring high-voltage floating ground signals, use isolated ground (LO / ground) to avoid common ground interference.

Fuse Replacement: When the current range is overloaded, turn off the power supply and replace the 3 A fast-acting fuse after.

(3) Maintenance and Calibration

Regular Calibration: Calibrate once every 2 years using a NIST traceable standard source; internal self-calibration can compensate for temperature drift in real time.

Cleaning and Maintenance: Use a dry cloth or soft brush to remove dust, keep the interface dry, and cover with a dust cap when not in use for a long time.

Environmental Control: Working temperature 0 ℃ to 40 ℃; avoid high temperature and high humidity to extend module lifespan.

Avoid Overload: Do not exceed the range (e.g., 1000 V range input > 1000 V) to prevent internal circuit damage.