Central subassembly for a flexible expandable automation device

A central subassembly for a flexible expandable automation device, comprising:

• a housing;
• at least one external expansion module connectable via an input/output bus;
• a first electronic subassembly having a central processing unit in a form of a first microcontroller, a volatile memory configured to store at least one of data of an operating system, data of an application program and variables of the application program, and a flash memory for non-volatile buffering of the data;
• a second electronic subassembly having a plurality of second inputs and second outputs each configured to connect each of a plurality of process signals;
• a third electronic subassembly configured to supply voltage to the central subassembly, the first, second and third electronic subassemblies being disposed in the housing;
• and
• at least one application program executable by at least one of the first microcontroller and the operating system, the at least one application program being stored in at least one of the volatile memory and the flash memory, wherein the at least one application program includes a first function configured to store the data in the flash memory when the voltage supply fails and a second function configured to copy the data previously stored in the flash memory to the volatile memory when the voltage supply returns.