ENGINEERS can dramatically reduce the time it takes to make accurate measurements with National Instruments PXI-4070 FlexDMM - a full-featured 6½-digit digital multimeter (DMM) in a single-slot 3U PXI module.
The FlexDMM delivers the accuracy of a 6½-digit DMM along with the advanced features and throughput of higher resolution DMMs that cost thousands of dollars more.
These advanced features include a 1.8MS/s fully isolated digitiser mode, self-calibration, and offset compensated ohms measurement.
The NI FlexDMM delivers six parts per million basic 24-hour dc voltage accuracy and sub μV sensitivity. The FlexDMM offers a continuously variable dc reading rate from 100S/s at 6½ digits to 5kS/s at 4½ digits.
With NI LabVIEW and NI-DMM driver software, engineers can extend the resolution of the FlexDMM to seven digits at 5S/s.
The architectural design of the FlexDMM incorporates a 1.8MS/s isolated digitiser. In isolated digitiser mode, the FlexDMM can acquire both ac and dc-coupled waveforms up to ±300V input, at a maximum sample rate of 1.8MS/s.
By combining NI LabVIEW software with the isolated digitiser mode, the FlexDMM can analyse transients, flyback signals, or other nonrepetitive high-voltage ac waveforms in both the time and frequency domain.
The NI PXI-4070 FlexDMM achieves ac measurement speed by solving a traditionally analog problem of rms-to-dc conversion in the digital domain.
The FlexDMM uses a digital algorithm that automatically rejects the dc component of the signal, making it possible to offer a dc-coupled ac voltage mode that bypasses the slow-settling input coupling capacitor required with traditional methods.
With this digital approach, the FlexDMM achieves ac measurement reading rates up to 2kS/s.
The FlexDMM inherently improves system integration because the PXI platform combines the high-speed PCI bus with integrated timing and triggering to deliver a more than 10X performance improvement compared to older architectures.
The speed, accuracy, and functionality of the FlexDMM make it suitable for demanding automated test and validation applications on the production floor and in the research and development laboratory.
NI-DMM driver software, which ships with the FlexDMM, is optimised for use in LabVIEW, LabWindows/CVI, Visual Basic, and Visual C/C++.
With the NI-DMM driver software, engineers can measure thousands of channels, consisting of voltages, thermocouples, and RTDs by seamlessly integrating the FlexDMM with NI's PXI switches, SCXI switches, and NI Switch Executive switch management software.
The currently shipping instrument driver, NI-DMM version 2.0, supports all of the previously described high-performance DMM features of the NI PXI-4070 FlexDMM.
Users can enable the isolated digitiser feature with a free upgrade to NI-DMM version 2.1 due for release in early 2003.
The NI PXI-4070 FlexDMM extends the acquisition capabilities of virtual instrumentation to 6½ digits. Virtual instrumentation systems add off-the-shelf mainstream computer technologies to measurement and automation software and modular hardware tools to create powerful computer-based instrumentation solutions.
With this approach, engineers can leverage the ever-increasing performance of personal computers to define measurement and automation solutions that meet their specific needs.
Engineers can use virtual instrumentation to build powerful applications for increasing productivity and performance throughout the enterprise - from research to design to the production floor.
The increase of processing speeds gives virtual instrumentation systems a competitive advantage that other measurements systems cannot claim.