Control device and method for controlling a redundant connection in a flat network

A method for controlling a redundant connection in a flat network architecture comprising at least two field devices;

• a primary control device connected to a primary switch by a first port of the primary switch;
• a secondary control device connected to a secondary switch by a first port of the secondary switch, wherein the primary control device and switch, the secondary control device and switch, and the at least two field devices are all connected together in a daisy chain loop topology using connections between the primary control device and the primary switch, the secondary control device and the secondary switch, the primary switch and the secondary switch, the primary control device and a first field device of the two field devices, the secondary control device and a second field device of the two field devices, and the first and second field device, wherein an Ethernet port of the primary switch is connected to a control room switch via a first connection, and an Ethernet port of the secondary switch is connected to the control room switch via a second connection that is separate from and provided for redundancy of the first connection, wherein the control room switch, the primary switch, and the secondary switch use Layer 2 of the Open Systems Interconnection (OSI) model for the first and second connections, the method performed in the secondary control device, the method comprising:
• operating in standby mode for the primary control device;
• detecting failure of the primary control device;
• initiating failover;
• and
• enabling the Ethernet port of the secondary switch, wherein the Ethernet port of the secondary switch is connected by the second connection via the control room switch to a control system.