Reel changer for a web-fed press and method for regulating a reel change

A method for regulating a reel changer of a web-fed press, the reel changer having a motor driving a printing material reel with a printing material web, a cascade control loop for regulating the rotational speed of the motor and therefore the circumferential speed of the printing material reel and the web speed of the printing material web to be unwound from the printing material reel, the cascade control loop comprising a current controller and a rotational speed controller superimposed on the current controller, the rotational speed controller outputting an output variable, and a position controller superimposed on the cascade control loop effecting a further cascade, the position controller controlling a position of a dancer roll acting on the unwound printing material web to provide a defined web tension, said method comprising the steps of:

• during a reel change, deactivating the position controller of the dancer roll to synchronize the circumferential speed of a new printing material reel with the circumferential speed of the printing material reel that is running out, and feeding a differentiated set point of the rotational speed controller to the output variable of the rotational speed controller as a feedforward control component, wherein the differentiated set point and the output variable form a set point of the current controller;
• and
• after the reel change has been performed, activating the position controller of the dancer roll and feeding a differentiated actual value of the position controller to the output variable of the rotational speed controller as a feedforward control component to form the set point of the current controller.