Patent ID: 7712415

Claim:
A method for driving a web-fed rotary printing machine including: providing a plurality of press units in said printing machine; providing a separate drive motor for each one of said plurality of press units; using each said separate drive motor for driving its one of said plurality of press units independently; providing a separate drive regulation unit for each one of said separate drive motors; providing a higher order control unit; using said higher order control unit for generating a single master shaft angular position set point of a virtual master shaft; providing a lower order drive control unit for each said drive regulation unit; providing at least one first signal line; using said at least one first signal line for carrying said master shaft angular position set point to each said lower order drive control unit for each said drive regulation unit; generating a separate individual offset value for each of said separate drive motors for each of said plurality of press units, each said separate individual offset value defining a displacement of said angular set point position of each one of said separate drive motors with respect to said single master shaft angular position set point carried to each one of said lower order drive control units; providing at least one second signal line; using said at least one second signal line for carrying said separate individual offset values to each said lower order drive control unit; generating a specific master shaft position for each said separate drive motor in each said lower order drive control unit using said single master shaft angular set point and each said separate individual offset value; determining an actual angular position of one of said plurality of press units prior to starting of said web-fed rotary printing machine; and using said actual angular position of said one of said plurality of press units for aligning said single master shaft angular position set point.