The Emulation, in the context of programmable instruments, is the process by which a new device is designed to imitate the functionality and, most importantly, the command language of an older or different device. An instrument running in an "emulation mode" will accept and respond to the command set of the device it is emulating, rather than its own native command set. This is a highly valuable feature for maintaining long-term test systems.
Often, a test station in a manufacturing line is built using a specific model of programmable power supply, and the control software is written to use that model's specific command language. Years later, that power supply model may be discontinued. If a replacement power supply is purchased, it might have a different, more advanced native command set. Without emulation, the existing, validated control software would need to be completely rewritten and re-validated, which is a costly and time-consuming process.
However, if the new power supply offers an emulation mode for the old model, it can be a "drop-in replacement." By simply configuring the new device to emulate the old one, it will correctly interpret all the commands from the existing software, allowing the test station to continue operating with no software changes. This preserves the investment in software development and validation and minimizes production downtime.