Distinguish between PLC-based control and SCADA supervision; how do they interact in an industrial plant?

Distinguish between PLC-based control and SCADA supervision; how do they interact in an industrial plant?

• A. SCADA directly executes real-time control at field devices, while PLCs serve only as data loggers.
• B. PLC executes real-time logic at the field level; SCADA collects data from PLCs, provides centralized monitoring, alarming, and reporting; SCADA often hosts HMIs and historians.
• C. PLC and SCADA perform identical roles and are redundant.
• D. SCADA operates completely independently with no data exchange with PLCs.

Answer: (B)