Patent ID: 7139622
Filing Date: 2006-11-21
Classification: G05B

Abstract:
1. A method of programming a failsafe control system having an input stage for receiving input signals, an output stage for providing output signals, and a processing stage for executing a failsafe control program, said method comprising the steps of: providing a set of predefined function-specific program modules comprising first program modules configured to pick up the input signals in a failsafe manner and to provide first interim variables in response thereto, second program modules configured to generate second interim variables corresponding to logical interconnections between said first interim variables, and third program modules configured to assign said second interim variables to said output signals, providing a graphic user interface having a display screen with a programming area that is divided into at least first, second and third sub-areas; assigning a graphic symbol to each of said program modules; selecting a plurality of the first, second, and third program modules from the set of program modules, and combining the program modules selected to form the failsafe control program by selectively placing the graphic symbol assigned to each of said selected plurality of first, second and third program modules into one of said first, second and third sub-areas in said programming area on said display screen; wherein the graphic symbol assigned to a first program module can only be placed in the first sub-area, the graphic symbol assigned to a second program module can only be placed in the second sub-area, and the graphic symbol assigned to a third program module can only be placed in the third sub-area; and further, wherein the placement of said graphic symbols within each of said sub-areas in said programming area on said display screen determines the interconnection of the selected program modules in the failsafe control program.