{"id":"opc-ua","model_id":"OPC-UA","name":"OPC UA","summary":"OPC Unified Architecture is a platform-independent standard for exchanging industrial data. Servers expose an address space of typed nodes that clients browse, read, write and subscribe to. Security is built into the protocol through signed and encrypted sessions.","study_notes":["Everything in an OPC UA server is a node with a NodeId. Nodes are linked by references, which lets a client browse a machine like a file tree.","Subscriptions let a client receive value changes without polling."],"safety_notes":["Security mode None disables signing and encryption. Use Sign or SignAndEncrypt outside a lab."],"sources":[{"url":"https://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?search=opcua","title":"IANA Service Name and Transport Protocol Port Number Registry (opcua-tcp, opcua-tls)","accessed":"2026-10-25"},{"url":"https://reference.opcfoundation.org/","title":"OPC UA Online Reference","accessed":"2026-10-25"}],"verification":{"status":"source_checked","checked_at":"2026-10-25","values":7,"method":"llm_source_check"},"updated_at":"2026-10-25","type":"protocol","spec":{"transports":["tcp"],"architecture":"client_server","encoding":"binary","default_ports":[{"port":4840,"transport":"tcp","secure":false,"purpose":"OPC UA Connection Protocol"},{"port":4843,"transport":"tcp","secure":true,"purpose":"OPC UA TCP Protocol over TLS/SSL"}],"data_types":[],"related":[]},"url":"https://machineschema.com/protocol/opc-ua","license":"https://creativecommons.org/licenses/by/4.0/"}