Redundant control for a process control system

1. A command redirection device for a process control system, the process control system comprising:

a main control device for controlling primary equipment of a primary system; and

a backup control device for controlling the primary equipment in case of a failure of the main control device,

wherein the command redirection device is adapted to receive a control command destined to the main control device, and redirect, in the event of a failure of the main control device, said control command to the backup control device, and

wherein the command redirection device is adapted to modify a confirmation message confirming the execution of the control command and transmitted by the backup control device by replacing an identification of the backup control device included in the confirmation message with an identification of the main control device.

2. The command redirection device of claim 1 , wherein the command redirection device is adapted to detect a failure of the main control device.

3. The command redirection device of claim 1 ,

wherein the control command comprises an identification of the main control device, and

wherein, for redirecting the control command, the command redirection device is adapted to modify the control command by replacing the identification of the main control device with an identification of the backup control device.

4. The command redirection device of claim 3 ,

wherein the command redirection device is adapted to request the identification of the backup control device by sending the identification of the main control device to an identification device, and to receive the requested backup identification from the identification device in response.

5. The command redirection device of claim 1 ,

wherein the command redirection device has a first communication interface for connection to a command device, the command device being adapted to generate the control command,

wherein the command redirection device is adapted to receive the control command from the command device,

wherein the command redirection device has a second communication interface for connection, via a data network, to the main control device and the backup control device, and

wherein the command redirection device is adapted for transmitting the control command to the main control device and the backup control device.

6. The command redirection device of claim 1 ,

wherein the process control system comprises a further main control device for controlling a further primary equipment of the primary system,

wherein the backup control device is adapted for controlling the further primary equipment,

wherein the command redirection device is adapted to detect a failure of the further main control device, and

wherein the command redirection device is adapted to redirect a control command for the further main control device to the backup control device, if a failure of the further main control device has been detected.

7. A process control system for a primary system, comprising:

a command device for generating control commands for a piece of primary equipment;

the main control device for controlling the piece of primary equipment of the primary system;

the backup control device for controlling the piece of primary equipment in case of a failure of the main control device; and

the command redirection device of claim 1 .

8. The process control system of claim 7 , comprising:

a data network,

wherein the main control device and the backup control device are connected to the data network,

wherein the control command is a data package transmitted by the data network,

wherein the main control device is identified by a first network address,

wherein the backup control device is identified by a second network address, and

wherein the command redirection device transmits, over the data network, the data packages to the main control device and the backup control device.

9. The process control system of claim 7 , comprising:

a further main control device,

wherein the backup control device is configured to perform the control functionality of the main control device, if a failure of the main control device has been detected by the command redirection device, and of the further main control device, if a failure of the further main control device has been detected by the command redirection device.

10. The process control system of claim 8 , comprising:

a further main control device,

wherein the backup control device is configured to perform the control functionality of the main control device, if a failure of the main control device has been detected by the command redirection device, and of the further main control device, if a failure of the further main control device has been detected by the command redirection device.

11. A SCADA system, comprising:

the command redirection device of claim 1 ,

wherein the SCADA system is adapted for generating the control command.

12. The SCADA system of claim 11 ,

wherein the command redirection device is adapted to detect a failure of the main control device.

13. The SCADA system of claim 11 ,

wherein the control command comprises an identification of the main control device, and

wherein, for redirecting the control command, the command redirection device is adapted to modify the control command by replacing the identification of the main control device with an identification of the backup control device.

14. The SCADA system of claim 11 ,

wherein the command redirection device is adapted to request the identification of the backup control device by sending the identification of the main control device to an identification device, and to receive the requested backup identification from the identification device in response.

15. The SCADA system of claim 11 ,

wherein the command redirection device has a first communication interface for connection to a command device, the command device being adapted to generate the control command,

wherein the command redirection device is adapted to receive the control command from the command device,

wherein the command redirection device has a second communication interface for connection, via a data network, to the main control device and the backup control device, and

wherein the command redirection device is adapted for transmitting the control command to the main control device and the backup control device.

16. The SCADA system of claim 11 ,

wherein the process control system comprises a further main control device for controlling a further primary equipment of the primary system,

wherein the backup control device is adapted for controlling the further primary equipment,

wherein the command redirection device is adapted to detect a failure of the further main control device, and

wherein the command redirection device is adapted to redirect a control command for the further main control device to the backup control device, if a failure of the further main control device has been detected.

17. A method for a process control system with a main control device and a backup control device being adapted for controlling primary equipment of a primary system, the method comprising the steps of:

detecting a failure of the main control device;

redirecting a control command destined for the main control device to the backup control device, if the failure of the main control device has been detected; and

modifying a confirmation message confirming execution of the control command and transmitted by the backup control device by replacing an identification of the backup control device included in the confirmation message with an identification of the main control device.

18. A non-transitory computer-readable medium, in which a computer program for a process control system with a main control device and a backup control device being adapted for controlling primary equipment of a primary system is stored, which, when the computer program is executed by a processor, the processor executes a method comprising:

detecting a failure of the main control device;

redirecting a control command destined for the main control device to the backup control device, if the failure of the main control device has been detected; and

modifying a confirmation message confirming execution of the control command and transmitted by the backup control device by replacing an identification of the backup control device included in the confirmation message with an identification of the main control device.