High accuracy 7½-digit DMM in PXIe format

April 28, 2016 // By Graham Prophet
National Instruments' PXI Express DMM forms, the company says, the foundation for more accurate, smarter test systems: PXIe-4081 is a 7½-digit high-performance DMM and 1.8 Msample/sec isolated digitiser. NI positions it as the first PXI Express DMM available.

The NI PXIe-4081 is claimed as the most accurate 7½-digit DMM, with 15 ppm accuracy for DC voltage measurements up to two years after calibration. It is capable of voltage measurements from nanovolts to one kilovolt and resistance measurements from microOhms to GigaOhms. A solid-state current shunt configuration offers eight DC current ranges from 1 µA to 3A and six AC rms current ranges from 100 µA to 3A. The DMM occupies a single 3U PXI slot and provides excellent channel density for high-channel-count systems, delivering 17 DMM channels in a single PXI chassis occupying 4U of rack space. For high-throughput applications, the isolated digitiser mode can acquire DC-coupled waveforms in all voltage and current ranges with a 1.8 Msample/sec maximum sample rate. By changing the digitiser sampling rate, engineers can vary the resolution of the digitiser from 10 to 23 bits to trade speed and accuracy.

Engineers can use an interactive soft front panel for basic measurements and debugging automated applications, which delivers all the ease-of-use expected from a traditional instrument. The driver software includes a programming interface that works with a variety of development environments, such as C, Microsoft .NET and NI's LabVIEW. The driver also features help files, documentation and 28 ready-to-run example programs to assist in test code development.

“Customers often choose the PXI platform to lower their cost of automated test based on the accuracy, channel density and speed of PXI instruments,” said Steve Warntjes, NI Vice President of R&D, Modular Instruments. “The NI PXIe-4081 ...[provides] a code-compatible migration option to PXI Express, extending the lifecycle of critical test and measurement functionality and doing it at the highest performance levels possible.”

NI has a paper on the use of the instrument, downloadable here.

National Instruments, www.ni.com