# SCADA **Domain:** Industrial Control / Infrastructure **Doc Type:** Technical Concept Node **Maturity:** Developed ## Definition **SCADA**, Supervisory Control and Data Acquisition, is an architecture for observing and influencing geographically or functionally distributed physical processes from supervisory systems. ## Governing Variable SCADA governs supervisory awareness and command: field measurements, alarms, equipment status, setpoints and selected remote operations. ## Material and Computational Manifestation Remote terminal units or controllers collect field state; communications carry it to supervisory servers and operator interfaces; historians preserve time series; commands return to controlled equipment. Local controls may continue operating even when the supervisory layer is unavailable. ## Relation to Governance SCADA is a concrete example of logical centralization without complete physical centralization. It gives higher layers visibility and reserved intervention capacity while local equipment executes detailed control. ## Constitutional Question and Failure Modes The operator's screen is an [[wiki/Operational Representation|operational representation]], not the process itself. Stale telemetry, misleading alarms, compromised communications or model mismatch can therefore produce confident intervention into a reality the supervisory layer no longer sees accurately. ## Related Ontology [[wiki/Industrial Control System|Industrial Control System]] · [[wiki/Operational Technology|Operational Technology]] · [[wiki/Telemetry|Telemetry]] · [[wiki/State Estimation|State Estimation]] · [[wiki/Control Plane|Control Plane]]