Abstract: An emulator, a system, and a method for emulating at least one controller of at least one technical facility, wherein an emulator is extended by at least one simulation of an operating system functionality and by a simulation of at least one system functional building block of the controller for high-availability communication to specify an emulation solution which is able to communicate with high reliability with real components from the automation environment through at least one network card and/or a communications processor and at least one communications layer for producing the high-availability communication. The system is networked with the technical facility following the loading of a facility configuration.