Glossary · Automation fundamentals, platforms and components
Virtual instrument (VI)
Also known as: VI, LabVIEW VI
German: Virtuelles Instrument (VI)
In measurement and test engineering, a virtual instrument (VI) is software, combined with general-purpose computer and data acquisition hardware, that performs the functions of a traditional measuring instrument. In NI LabVIEW, every program or subroutine is called a VI and consists of a front panel and a block diagram.
- Automation components
- Vendor product
In one sentence
A virtual instrument (VI) is software plus data acquisition hardware acting as a measuring instrument; in NI LabVIEW, every program is a VI.
Example
The test bench uses a LabVIEW VI that acquires motor current and vibration, displays them live and stores each test run with the serial number.
How it applies
- Engineering: Virtual instruments are used for test benches, end-of-line testing and laboratory automation. The accuracy of results depends on the acquisition hardware, Sampling time, signal conditioning and Calibration, not only on the software.
- Validation: When VIs produce test evidence, they need version control and validation like any test software. Keep VIs under Version management.
- Documentation: Test specifications should name the VI version, hardware and settings used. User documentation for test benches explains the front panel and what each result means. Record the calibration status of the acquisition hardware with each test report. Name the author and reviewer of each VI used for release decisions.
Keep in mind: Product names and features change. Check LabVIEW versions and capabilities against NI's current documentation.