1. A method of creating a function block for use with a process control system, comprising: selecting an initialization routine from a plurality of source files; selecting a periodic execution routine from the plurality of source files; selecting a write checking routine from the plurality of source files; associating the initialization routine, the periodic execution routine and the write checking routine with the function block; and modifying one of the initialization routine, the periodic execution routine and the write checking routine to include a procedure that is not provided with the process control system.