A function block engine, a block execution list and a parameter and/or variable storage space being resident in a memory supporting the engine. The function block engine may execute a program according to a list of function blocks identified in the block execution list to design and construct and circuit or system. Also, the engine may provide simulation of the resultant circuit or system. The circuit or system may be transferred to a memory of another device for implementation and use as, for example, a controller. In some cases, the program may be executed from the memory. The engine may permit field programmability, configuration and simulation of the function blocks and resulting circuit or system.