An assembly for synchronizing machine operations, the assembly comprising: a reference generator for generating a speed reference signal (140, 171) and a position reference signal (155, 173); a plurality of slave units (50, 55, 110, 110a, 111), each slave unit including: a mechanical device (35, 40); a separate motor (112, 112a) linked to and driving the mechanical device (30, 35, 40); and a separate unit controller (114, 114a) for controlling the unit motor, the unit controller receiving and using the reference signals to control motor operation; a synchronizer for generating a task synchronization signal, receiving the reference signals, simultaneously providing the reference signals to each of the slave unit controllers for use in controlling operation of the motors in a synchronized fashion and for providing the task synchronization signal to the unit controllers (114, 104) for synchronising execution of tasks; and a master unit including the reference generator, at least one delay element (150, 160), a master mechanical device, a master motor linked to and driving the master mechanical device and a separate master unit controller for controlling the master motor, the master unit controller receiving and using the reference signals (140, 155) to control motor operation, the at least one delay element (150, 160) located between the reference generator and the master unit controller to delay reception of the reference signals at the master unit controller during the period over which the reference signals are transmitted to the slave unit controllers, wherein the synchronizer is adapted to generate and provide periodic synchronization signals to the unit controllers (114, 114a) indicating times at which the reference signals are to be used by the unit controllers to control motor operation. a reference generator for generating a speed reference signal (140, 171) and a position reference signal (155, 173); a plurality of slave units (50, 55, 110, 110a, 111), each slave unit including: a mechanical device (35, 40); a separate motor (112, 112a) linked to and driving the mechanical device (30, 35, 40); and a separate unit controller (114, 114a) for controlling the unit motor, the unit controller receiving and using the reference signals to control motor operation; a mechanical device (35, 40); a separate motor (112, 112a) linked to and driving the mechanical device (30, 35, 40); and a separate unit controller (114, 114a) for controlling the unit motor, the unit controller receiving and using the reference signals to control motor operation; a synchronizer for generating a task synchronization signal, receiving the reference signals, simultaneously providing the reference signals to each of the slave unit controllers for use in controlling operation of the motors in a synchronized fashion and for providing the task synchronization signal to the unit controllers (114, 104) for synchronising execution of tasks; and a master unit including the reference generator, at least one delay element (150, 160), a master mechanical device, a master motor linked to and driving the master mechanical device and a separate master unit controller for controlling the master motor, the master unit controller receiving and using the reference signals (140, 155) to control motor operation, the at least one delay element (150, 160) located between the reference generator and the master unit controller to delay reception of the reference signals at the master unit controller during the period over which the reference signals are transmitted to the slave unit controllers, wherein the synchronizer is adapted to generate and provide periodic synchronization signals to the unit controllers (114, 114a) indicating times at which the reference signals are to be used by the unit controllers to control motor operation.