| 摘要 |
OPC data is transmitted via data networks, in particular the Internet. A bi-directional data connection via the Internet in both directions, is enabled even across firewalls and starting from an OPC client, which is not visible as a server on the Internet. To achieve this, a first connection request for establishing a first transmission channel is sent from a first data processing device of an OPC client, via a data connection, to an OPC server of an automation system. The OPC server responds to the request using a second transmission channel. The data connection is thus kept open permanently, allowing data to be sent and received bi-permanently, allowing data to be sent and received bi-directionally, said operations being temporally independent of each other, between the OPC client and the OPC server by at least one data network, in particular, the Internet. To guarantee a temporally unlimited service life of a data connection, dummy data is transmitted, for example, at regular intervals from the OPC server to the OPC client, even if no useful OPC data is present, in order to maintain at least one data connection.
|
