# Supported Features

The Cognex Designer OPC UA server implementation is a simple one. The following basic functionality are the only supported features:

- Anonymous connection to the server only.

  For example, username & password connection to the server is not supported.

- Executing method nodes

- Reading/writing variable nodes

  Writing to an index of an array is not supported (rewriting the whole array does work)

- Subscriptions to variable nodes (monitor 500 items per subscription, 3 subscriptions total)

- Multiple client connections (at least 50 parallel sessions)

  Transferring subscriptions to another client session is not supported

The Cognex Designer OPC UA plug-in does not full implement any of the OPC UA Server Profiles.

Note: The Cognex Designer OPC UA Server certificate that is automatically generated expires after 1 year. This limitation requires a yearly workaround to stop the server and delete the certificates located at %ProgramData%\Cognex\Designer\Certificates\own before restarting the server.