Method for operating an automation device

The method involves supplying electrical energy from two source modules (4-6) to multiple sink modules (9-N) by the supply lines (P1,P2). The applied voltage representing the rated power of the modules, is detected by an evaluation unit (7). The percentage capacity level of an automation device with respect to the total output power on the supply lines is derived from the applied voltage and a characteristic curve. A controllable switch (8) connected to the respective modules, is driven with the supply lines based on the capacity level. An independent claim is included for an automation device.