ABB SPA OPC Server User Manual page 63

Local DCOM configuration
Sometimes it is necessary to configure DCOM even when the server and client run on the
same computer. This is the case when two clients that are running in different user
accounts must both access the same server. For example, an alarm and event client
running as a service and an interactive data access client.
If the server is configured to run as the "Launching User", only the client that connects
first will succeed to get a connection. This is due to how COM works. The solution is to
configure the server to run either as the "Interactive User" or in a specific user account
("This user:").
If the server is configured to run in a specific user account, its user interface will not be
visible when it is activated by the COM runtime. This is because it is not started in the
interactive desktop. The only place where it is visible is the Task Manager.
If the server is configured to run as the "Interactive User", it will be terminated when the
interactive user logs off. This is not desirable, for example, if the client is an alarm
service that is always running.
1MRS755221
The server should not be started manually, if it is configured in this way. In that
case, the clients that are running in other user accounts will not be able to
access it although it is correctly configured.
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