Visual Basic for Applications (VBA) is the programming language of Microsoft Office and is a version of Visual Basic that is built into most Office applications, including Excel, Word, and Access. VBA allows users to automate repetitive tasks, create custom functions, and build complex applications within the familiar environment of an Office product. For engineers and technicians, Excel with VBA is a particularly powerful and accessible tool for test automation and data analysis. A user can write a VBA script (called a "macro") directly within an Excel spreadsheet. This script can use communication libraries like VISA (via a COM interface) to control programmable instruments like power supplies.
For example, a VBA macro could be written to perform a test sequence: it would send commands to a power supply to step through a series of voltage levels, and at each step, it would command a multimeter to take a reading. The macro would then automatically pull the measurement data from the multimeter directly into the cells of the Excel spreadsheet. Once the data is in the spreadsheet, the user can leverage all of Excel's built-in tools for analysis, charting, and reporting. This ability to combine instrument control, data acquisition, and data analysis in a single, widely available application makes VBA a popular choice for simple to moderately complex lab automation tasks.