System and method for the operator control and for the monitoring of an automation system over the internet using an asymmetric internet connection

A system for transmitting data bidirectionally and asymmetrically across a single connecting line over the Internet between an Internet server and a client connected to the Internet behind a firewall computer proxy via an internal data network, the system comprising:

• an Internet server;
• a client connected to the Internet behind a firewall computer proxy via an internal data network having an IP address valid only in a local network and thus not being visible on the Internet;
• and, wherein the client is configured to transmit a first connection request on a connecting line for setting up a first transmission channel on the connecting line via an Internet connection to the Internet Server, the Internet server is configured to transmit to the client a first response to the first connection request, the first response establishing the first transmission channel on the connecting line as a back channel and including connection data for subsequently establishing a second transmission channel on the connecting line via an Internet connection to the Internet Server, wherein the first transmission channel is not released with the first response;
• the client is further configured to transmit a second connection request for setting up a second transmission channel on the connecting line via an Internet connection to the Internet Server using the connection data, wherein the first and second connection requests are successively transmitted, the Internet Server is further configured to transmit to the client a second response to the second connection request, the second response establishing the second transmission channel on the connecting line as a forward channel;
• the client and the Internet Server configured to maintain the first and second channels on the connecting line by transmitting dummy data therebetween during an absence of user data to ensure an unlimited period of use;
• the first transmission channel and the second transmission channel on the connecting line are configured to bidirectionally transmit and receive on the connecting line, independently of one another in terms of timing, data between the client and the Internet Server over the Internet, wherein the back channel on the connecting line is for transmitting responses from the Internet Server to the client in reply to client requests on the forward channel and for transmitting messages to the client without the client having previously made a request on the forward channel, and the forward channel on the connecting line is for transmitting requests from the client to the Internet Server;
• wherein data for operating and monitoring an automation system is provided over the Internet, the first transmission channel used for transmitting status data of the automation system to the client, and the second transmission channel used for transmitting requests from the client to the automation system;
• wherein the client is an operator control and monitoring system which initiates the transmission channels as a DCOM object, and the setup of the connection to the automation system is made via a DCOM server.