Patent ID: 8402192

Claim:
A modularly constructed field device of process automation technology having; a basic card with an executable, basic program; and at least one expansion card containing at least one, executable, expansion program, wherein: for executing said basic program, said basic card comprises at least one computing unit and a first memory unit matched to the memory requirement of said executable, basic program which contains a first data memory and a first program memory; said at least one expansion card comprises at least a second memory unit designed for memory requirement of said executable, expansion program which contains a second data memory and/or a second program memory; an automatic detecting of the connected said at least one expansion card is provided by said basic card; for expanding said basic program by said expansion program, a partial and/or intermittent accessing of said second memory unit by said at least one computing unit is provided, and global program flow lists is provided, which control the logical program execution since the individual functions of the basic program and the expansion programs are distributed on the different memory units.