Devices might support Sleep Mode WOL functionality allowing to switch off a device almost completely. If this Sleep Mode WOL functionality is active, the device in Sleep Mode WOL is not reachable for network communication and can only be ‘awakened’ by receiving a ‘WOL magic packet’. The energy consumption of a device in Sleep Mode WOL is caused by the power to keep the network MAC controller alive while Standby Management demands an application on the device to monitor and control the Standby Management states. Therefore, Sleep Mode WOL typically consumes less power than Standby Management.

The transition to the Sleep Mode WOL state is initiated by invoking the SwitchOffWOL Method of the EnergyDevicePowerOffType defined in 7.3.1.

If the switched off device contains the OPC UA server, the connection of the OPC client to the server disconnects. The server will be reachable again after a wake up of the device by WOL (sending the WOL magic wake-up packet).