From Industrial Automation to Intelligent Automation: The Impact of IIoT on Process Control - A Review?

The Industrial Internet of Things (IIoT) is reshaping process control, turning torrents of plant data into near-instant insight. Field evidence already shows unplanned-downtime cuts of 55%, maintenance-budget savings of 40%, and gains in overall-equipment-effectiveness of roughly 15%; nevertheless, fewer than 30% of facilities have pushed beyond pilot scale to full, always-on predictive maintenance. To clarify why, this review screens 312 Scopus records published between 2010 and 2023, then subjects 62 peer-reviewed studies and a broad set of industry reports to deep content analysis, bibliometric mapping, and thematic clustering.The results reveal four tightly connected research fronts—IIoT/Industry 4.0 core technologies, classical process-control theory, data-driven intelligence, and enabling infrastructure—with cybersecurity emerging as the fastest-growing theme. Across the surveyed literature, the synergistic use of edge computing, artificial intelligence, blockchain, and advanced wireless sensor networks demonstrably sharpens anomaly detection, accelerates control-loop response, and improves energy efficiency. At the same time, persistent obstacles—expanded attack surfaces, legacy-system interoperability, data-management overload, and fragmented standards—continue to throttle large-scale adoption.Drawing on comparative case studies from manufacturing, oil and gas, power generation, and water treatment, the paper distils actionable design rules: adopt zero-trust architectures with lightweight authentication at the edge; pair federated-learning filters with certified robust inference to resist data poisoning; and deploy delay-aware computation-offloading schemes that trade cloud muscle for millisecond-class responsiveness and extended battery life. A forward-looking agenda highlights open questions around sub-100 ms secure aggregation, benchmark metrics for energy-aware offloading, and cross-vendor interoperability for 5G-and-beyond networks.By unifying quantitative trends with hard-won field lessons, this synthesis provides researchers, control engineers, and plant managers a clear playbook for building robust, secure, and high-performance intelligent-automation systems—and charts the research paths most likely to unlock IIoT’s full industrial promise.