Integration·7 min read
OPC-UA and MQTT Backbone Design
One namespace, many vendors in chemical plants — a practical architecture guide.
OPC-UAMQTT
Namespace design
Vendor-agnostic tag model under one OPC-UA namespace — lowers maintenance cost. Tag naming is fixed to the ISA-95 hierarchy; when a new PLC is added, only the mapping layer is updated.
The MQTT topic schema stays in `site/line/unit/metric` format; historian and MES share the same topic dictionary.
Bridge and QoS
QoS1 + backpressure for burst traffic on the OPC-UA → MQTT bridge; edge gateway keeps a 15-minute local buffer.