1. An apparatus for operating in a block-oriented open control system comprising: a memory, which includes system management data and a flexible function block; wherein the system management data includes a system schedule; wherein the flexible function block includes end-user configured parameters and an end-user configured algorithm; a processor, operably connected to the memory, wherein the processor executes the flexible function block based on the system schedule; and a medium attachment unit, which translates input messages and output messages between the processor and a transmission medium.