NI PXI-4022

NI PXI-4022 is officially documented by NI as a Guard and Current Amplifier, not as a standalone digital multimeter. NI describes the module as an accessory PXI module and a high-speed, high-precision amplifier that conditions signals for acquisition by other measurement devices. The basic structure is a unity gain amplifier, and NI also states that it can function as a preamplifier for low-level current measurements. This positioning is important when distinguishing the device family from NI DMM products, because NI-DMM readme documentation lists PXI-4022 under PXI Amplifier Module rather than under PXI Digital Multimeter products.

For measurement use, NI documents the PXI-4022 for applications including 6-wire guarded measurements and low-current measurements. The guard amplifier specification is 1 V/V with ±0.0015% gain accuracy, while the current amplifier transimpedance gain is 10,000 V/A with ±0.0015% gain accuracy. NI also specifies 10 GΩ || 110 pF input resistance, making the module suitable for sensitive signal-conditioning roles ahead of a separate measurement instrument.

Key electrical limits from the NI specifications include a maximum working voltage of 250 VAC CAT II or 300 VDC, overvoltage protection of ±300 VDC/250 VAC on HI and LO whether powered on or off, and a maximum current into the current input of 20 mA DC or AC rms. The output voltage range is ±10 V. Dynamic performance is specified as greater than 50 V/µs slew rate and greater than 1 MHz small-signal bandwidth.