GIVING CLIENTS ACCESS TO A SERVER SERVICE USING AN OPC-UA

摘要

The invention relates to a method for giving clients (1, 2, 3) access to a service of a server (4) in a network using an OPC-UA, said server service making available varying values of at least one variable (var1) to the clients (1, 2, 3). A client (1, 2, 3) registers for the server service by sending a subscription request (5.1, 5.2, 5.3) for the server service to the server (4). For the server service, the server (4) sets up a subscription structure (S1, S2, S3) including a unique subscription ID as well as a TCP/IP multicast group (9) which is associated with said subscription structure (S1, S2, S3) and which includes a unique multicast address, and communicates the multicast address and the subscription ID to every client (1, 2, 3) submitting a subscription request (5.1, 5.2, 5.3) to register for the server service. The server (4) sends each change in value of each variable (var1) of the server service to the multicast address via the network by means of a multicast message (8) so that all clients (1, 2, 3) registered for the server service receive the same multicast message (8).