ISA-95 is the international standard that describes how plant-floor control systems and business systems should exchange information. It gives engineers and IT a shared vocabulary - and a layered model - for connecting sensors, PLCs, SCADA, MES, and ERP without every integration being a one-off. If you have ever heard someone talk about "Level 2" or "Level 4" of an automation stack, they are speaking ISA-95.
ISA-95 in one line: ISA-95 (ANSI/ISA-95, internationally IEC 62264) is a standard that defines the models, terminology, and interfaces for integrating enterprise systems with industrial control systems, organized into functional levels from field devices up to business planning.
ISA-95 organizes an operation into a hierarchy of levels. Level 0 is the physical process itself - the wells, separators, and pipelines. Level 1 is the sensing and actuating layer: transmitters, valves, and instruments. Level 2 is monitoring and supervisory control - PLCs, RTUs, DCS, and SCADA. Level 3 is manufacturing operations management, where MES and MOM systems handle production scheduling, quality, and workflow. Level 4 is business planning and logistics, typically ERP.
The value of the model is that it clarifies which system owns which decision and on what timescale. Level 1 and 2 respond in milliseconds to seconds; Level 3 works in shifts and days; Level 4 in weeks and months. ISA-95 also defines standard object models - for production, material, equipment, and personnel - so a message about a batch or a run means the same thing on both sides of an interface.
Upstream and midstream operations rarely fit neatly into a factory model, but the layered thinking still applies. Field telemetry lives at Level 1 and 2, production volumes and allocation logic sit around Level 3, and hydrocarbon accounting rolls up into Level 4 financial systems. ISA-95 gives teams a clean way to describe where SCADA ends and the enterprise begins, which is exactly the seam where most integration projects succeed or fail.
In practice, a cloud SCADA platform occupies Level 2 and feeds structured data upward. Merobix reads field devices at Levels 1 and 2 over Modbus, DNP3, OPC UA, EtherNet/IP, S7, and MQTT, then exposes that data through APIs so Level 3 and 4 systems can consume it. Following ISA-95 boundaries keeps those handoffs predictable.
They are closely related and often used together. The Purdue model provides the layered network architecture; ISA-95 aligns its levels with that hierarchy and adds standardized object models and interface definitions for enterprise-control integration. In everyday use the two are frequently referenced side by side.
Yes. ISA-95 was adopted internationally as IEC 62264, so the two designations refer to the same body of work. ANSI/ISA-95 is the North American label and IEC 62264 is the international one.
You are not required to certify against it, but its levels and terminology are the common language most vendors, integrators, and enterprise architects already use. Applying the model makes it far easier to scope where SCADA connects to MES and ERP.
This page references the protocol specifications published by the organizations below. Editions, product capabilities, and documentation change over time - confirm current requirements and specifications directly with the source.
Last reviewed: July 27, 2026. Merobix is not affiliated with, endorsed by, or sponsored by these organizations; their names are used only to identify the standards and products discussed.
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