The Main-Follow function is based on a measurement of the current consumption at the Main socket.
If the measurement is above the set threshold, the follow sockets are automatically switched on.
If the measurement is below the set threshold, the follow sockets are automatically switched off.
However, for battery-powered devices such as laptops, the current consumption does not necessarily correspond to the operating state on or off.
The current consumption can also be above the threshold when the laptop is switched off (charging the battery) or below the threshold when the laptop is switched on (battery full and laptop operating at low power). Therefore, using battery-powered devices as the main device is usually unsuitable.