Open Automation in Process Industries: Transition from Proprietary DCS to Software-Defined Control Systems

Abstract: Industrial process control has relied on proprietary DCS for over five decades. The model worked. But working and working well are different things, and in 2026, the gap between what proprietary DCS delivers and what operators in manufacturing, oil and gas, chemical processing, and water treatment need has grown wide enough to drive real change. Vendor lock-in, hardware obsolescence that stretches across decades, and maintenance contracts that give a single supplier complete leverage over upgrade decisions are no longer tolerable when the alternative, open and software-defined control, has been proven at an industrial scale. The Open Process Automation Standard (O-PAS), the IEC 61499 function block model, and OPC UA connectivity together provide the technical foundation for software-defined control systems (SDCS) that break these dependencies. Documented lifecycle cost savings reach approximately 52% over twenty-five years when compared to equivalent proprietary DCS platforms [4]. This paper reviews the standards, examines real deployments, and confronts the barriers that still slow adoption, particularly the near-complete absence of IT-domain competencies in OT workforces. An original SoftwareDefined Automation Risk Mapping Model (SD-ARMM) is proposed, providing practitioners with a five-dimensional, riskdriven tool to determine which migration strategy fits their specific organisational and operational reality.