The Virtual Instrument Software Architecture (VISA) is a widely adopted standard API for communicating with test and measurement instruments from a computer. Defined by the IVI Foundation, VISA provides a single, consistent software interface for controlling instruments, regardless of the physical communication bus used. Before VISA, programmers required different library functions to control GPIB instruments versus serial (RS-232C) instruments, making it difficult to write flexible and portable test code.
VISA addresses this issue by creating an abstraction layer. Programmers can write code using standardized VISA functions--such as viOpen() to connect, viWrite() to send commands, and viRead() to receive responses. The VISA library automatically handles the low-level translation for specific physical interfaces, including GPIB, USB (USBTMC), LAN/Ethernet (LXI), and RS-232C. This interface independence allows test programs to adapt to different instruments with minimal code changes. VISA is a library specification implemented by various vendors (e.g., National Instruments, Keysight, Rohde & Schwarz) and is compatible with major programming environments like LabVIEW, C#, Python, and MATLAB.
A Unified Communication Solution
VISA enables control via the same software regardless of the interface type, eliminating the need for separate libraries for each bus. This standardization significantly reduces development time and simplifies the management of multiple devices simultaneously.
Note: Certain non-standard interfaces or legacy devices may not be supported by VISA and may require specific driver configurations.
National Instruments: https://www.ni.com/Keysight Technologies: https://www.keysight.com/
Tektronix: https://www.tek.com/
