Abstract: A process control system is provided which has at least one OPC client and one OPC server which communicate via a standardized OPC interface. Furthermore the process control system has at least two redundantly operated control devices which each communicate with the OPC server by means of a coupling device. Each control device is designed to provide process variables and status information. The status information contains the current role of the respective control device, wherein the current role is either that of a main control device or an auxiliary control device. The OPC server is designed to detect the main control device in response to the status information of at least one control device, to register a list of variables generated by the OPC client at the main control device and/or to transmit to the OPC client only the process variables which have been provided by the main control device.

Abstract: To simplify and/or improve error monitoring in a control and data transmission system for redundant process control, provided is a method for error monitoring in which errors detected by a first control device are stored locally as well as transmitted to at least one redundant second control device, which is arranged remotely, and also stored there so that in each case the error history of both control devices and is available locally for diagnosing the whole redundant system. Further provided is a control and data transmission system designed to carry out the method and a control device for use therein.

Abstract: To simplify and/or improve error monitoring in a control and data transmission system for redundant process control, provided is a method for error monitoring in which errors detected by a first control device are stored locally as well as transmitted to at least one redundant second control device, which is arranged remotely, and also stored there so that in each case the error history of both control devices and is available locally for diagnosing the whole redundant system. Further provided is a control and data transmission system designed to carry out the method and a control device for use therein.

Abstract: A process control system is provided which has at least one OPC client and one OPC server which communicate via a standardized OPC interface. Furthermore the process control system has at least two redundantly operated control devices which each communicate with the OPC server by means of a coupling device. Each control device is designed to provide process variables and status information. The status information contains the current role of the respective control device, wherein the current role is either that of a main control device or an auxiliary control device. The OPC server is designed to detect the main control device in response to the status information of at least one control device, to register a list of variables generated by the OPC client at the main control device and/or to transmit to the OPC client only the process variables which have been provided by the main control device.