Patent ID: 6233703
Filing Date: 2001-05-15
Classification: G05B,G06F

Abstract:
A computerized method for facilitating the development of a computer program documented in the form of a function block diagram in conformance with IEC standard 1131-3, said method comprising the steps of:providing a user with a graphical user interface fordefining at least two executable function blocks, each said function block including one or more input terminals and one or more output terminals, andconnecting, either directly or indirectly via other program elements, at least one said block output terminal of one said block to a respective said block input terminal of another said block;using the graphical user interface to define a function block diagram comprising at least two connected function blocks;automatically detecting in said diagram thus defined, any cyclic connections from an output terminal of given instance of a particular said block to an input terminal of the same instance of said particular block;if any said cyclic connection is detected, using said graphical interface to automatically highlight at least one said cyclic connection to said user; andif no such cyclic connection is detected, automatically determining an evaluation order for evaluating all said function blocks such that if a first block has an output terminal connected to an input terminal of a second block, said first block is evaluated before said second blockswherein both said detecting and determining steps utilize a recursive topological sort procedure in each iteration of which a respective evaluation ordinal is automatically assigned to a block which has not already been assigned any said evaluation ordinal and which does not lead to another block which had not previously been assigned any said evaluation ordinal.