OPC UA Information Model for Process Equipment (UA XML)

The OPC UA Information Model for Process Equipment leverages the object-oriented modeling capabilities of OPC UA to formalize equipment semantics beyond simple data point addressing. It defines standardized NodeSets—typically serialized in UA XML schema files—that encapsulate equipment classes (e.g., 'PumpType', 'ControlValveType') as subtype hierarchies inheriting from base types like 'EquipmentType' or 'ProcessCellType'. Each type includes mandatory and optional components: structured properties (e.g., 'Manufacturer', 'ModelNumber'), dynamic variables (e.g., 'ActualFlowRate', 'OperatingState'), methods (e.g., 'Start', 'Calibrate'), and condition alarms (e.g., 'OverTemperatureAlarm'). These models are semantically enriched using companion specifications—most notably OPC UA Part 100 (for process industries) and the OPC Foundation’s Process Automation Companion Specification—which map domain-specific concepts (e.g., ISA-88/ISA-95 equipment modules, S88/S95 states) to UA constructs. In practice, PLCs (e.g., Siemens S7-1500, Rockwell ControlLogix with UA servers) host these instantiated models, exposing them to MES, SCADA, or cloud platforms via secure, firewall-friendly binary or HTTPS endpoints. The UA XML representation allows tooling (e.g., UaModeler, ASNeG Model Compiler) to validate, version, and deploy models without runtime dependencies, supporting lifecycle management from engineering to commissioning and predictive maintenance.