Patent ID: 8121709

Claim:
A method for comparing variable values obtained from different versions of an application program in an automated system, said system comprising a controller for automation of a process by means of the application program stored therein, the application program cyclically performing task scans based on an input signal, characterised in that the method comprises the steps of: inputting to at least two different versions of the application program, which versions reside within the same controller, the input signal obtained from said process, executing, in the controller, the same task scan based on said input signal for the at least two different versions of the application program, storing in memory locations process related variable values obtained from the execution of said at least two versions, said memory locations being known by the controller, retrieving from the memory locations the variable values, and comparing the variable values for differences when said controller is idle, the comparison being made as an atomic operation in-between task scans.