Patent ID: 7272453
Filing Date: 2007-09-18
Classification: G05B

Abstract:
1. A method for controlling a process using a programmable logic controller (PLC) having a central processing unit (CPU) which includes a load memory which stores all instructions and data required for controlling the process and an interpreter that evaluates and executes instructions in a work memory to control the process, said method comprising the steps of: (a) creating instructions comprising a format that includes at least one option code that is coded as being enabled or disabled; (b) copying one instruction from said load memory to said work memory; (c) independently evaluating, by said interpreter, said at least one option code to determine if said option code is true; (d) executing said instruction if said option code is evaluated by said interpreter to be true, or not executing said instruction if said option code is evaluated by said interpreter to be false and if so to copy the next instruction from said load memory to said work memory and repeating step (c) for this next instruction; (e) checking to see if said instruction whose option code has been evaluated to be true has been completed and if not to continue to execute said instruction to completion; and (f) if said instruction whose option code has been evaluated to be true has been completed, repeating steps (b)-(f) until all of said instructions have been evaluated and executed where evaluation of said at least one option code in the corresponding instruction has been determined to be true.