DBT – Digital Box Technologies ·
OPC UA is the standard for industrial interoperability. It describes data with context (units, structure, state) and has built-in security. It is ideal for talking to PLCs and equipment.
MQTT is a lightweight publish and subscribe messaging protocol. It excels at efficiently moving large numbers of measurements to data platforms and the cloud.
In a modern architecture, OPC UA collects at shop-floor level, an Edge gateway translates, then MQTT distributes to consuming applications.
The choice depends on the need: semantic richness and control on one side, lightness and large-scale distribution on the other.
Compare requirements, not only protocols
OPC UA provides a framework for describing and exchanging industrial information. MQTT provides publish/subscribe messaging around a broker. They need not compete: a gateway may read equipment data through OPC UA and publish measurements to a collection system using MQTT. Check which capabilities your actual devices and versions implement.
Define what the data means
A value without context is difficult to use. Document measurement names, units, timestamps, quality and source equipment. For MQTT, agree a topic structure and versioned message format. For OPC UA, assess available models and how clients interpret them. Semantic consistency matters as much as establishing a connection.
Test permissions and interruptions
Restrict each client to necessary exchanges and configure appropriate authentication and protection for the chosen components. Plan certificate management where certificates are used. Test disconnection, restart and delayed or duplicate messages. Quality-of-service settings do not replace consistency checks in the consuming application.
Make a documented choice
Bring device references and versions, expected data volumes, measurement frequency, available interfaces and destination systems to the assessment. Include network constraints and workshop owners. The right choice meets the use case with observable, maintainable behaviour rather than adding the most components.