Definition
OPC UA (IEC 62541) is the modern communication standard that lets PLCs and machines on the factory floor talk securely and vendor-independently to higher-level software (SCADA, MES, ERP, cloud). Unlike Modbus it carries data together with its meaning: a temperature arrives with its unit, limits and the machine it belongs to. Encryption, authentication and authorisation are built in, which is why it is preferred for the bridge between IT and OT. Most new PLCs run as OPC UA servers; a gateway is used for older devices. It is the common language of Industry 4.0 and digital-twin projects.
How SMB Teknoloji uses it
We move production data to ERP, reporting and AI layers over OPC UA; for older PLCs we install a gateway and enable certificate-based security.