Control system for positioning units exhibiting dead time in their response to activating signals

A printing machine operates at a variable speed, and includes a rotary reference component. Activation and deactivation of positioning units for printing cylinders and other functional units for the printing machine is performed in synchronization with the rotation of the rotary reference component. The positioning units exhibit dead times in their response to applied activating or deactivating signals. The duration of each such dead time expressed in terms of the extent of angular movement of the rotary reference component varies in dependence upon printing machine operating speed, tending to produce improper synchronization between activation and deactivation of positioning units, on the one hand, and machine operation, on the other hand. The speed of operation of the printing machine is monitored and employed to automatically introduce a compensatory time delay into the application of activating or deactivating signals to the positioning units, to compensate for the dead times and maintain proper synchronization.