ISA-95 explained: the five levels and where an MES sits

The five levels

ISA-95, published internationally as IEC 62264, describes manufacturing as five connected levels.

Each level has its own responsibilities and its own timescale, from the physical process on the shop floor up to business planning at enterprise level.

Level	Name	What lives there	Timescale
4	Enterprise	Business planning and logistics: ERP, demand management, supply chain, finance	Weeks to months
3	Manufacturing Operations Management	MES: production execution, materials, quality, maintenance, traceability, performance	Minutes to shifts
2	Control and supervision	SCADA, HMI, batch control	Seconds
1	Sensing and actuation	PLCs, DCS, and edge devices	Milliseconds
0	The physical process	Sensors, actuators, motors, tanks, and the physical process or product itself	Continuous

Read top-down, the five levels form a chain of translation.

A customer order at Level 4 becomes a production process and activities at Level 3. From there it becomes instructions and control at Levels 2 and 1, until it finally produces a physical change at Level 0.

Read bottom-up, it becomes a chain of evidence.

A sensor reading becomes process data. That data is tied to an activity and a batch at Level 3. The result becomes the information needed for reporting and decision-making at Level 4.

This is what makes Level 3 matter. It turns data from the physical process into production context the business can understand, and it translates the business plan into something that can actually be executed on the shop floor.

Why Level 3 is the level people skip

Levels 4 and 2 usually already have clear systems in most plants. Almost every manufacturer has an ERP.

Plants running continuous or reasonably automated processes usually have SCADA and PLCs as well. These systems represent years of investment and generally remain an important part of the plant architecture.

Level 3 is often different.

This is where you still find the whiteboard, the shift-handover spreadsheet, the group chat, and information stored in the heads of the people running the process.

The Level 3 function does exist. It just does not live in one structured system.

That can hold up while operations stay relatively simple. The problems start when the plant has to prove what actually happened.

An audit wants to know which lot of raw material went into a batch. A customer complaint requires tracing a serial number through several assembly steps. A regulator asks who approved a deviation, and when.

Level 3 is where that execution context and evidence is supposed to live.

What the standard actually gives you

ISA-95 is not a product specification and it does not decide what software you should buy.

What it gives you is a structure and a shared vocabulary for describing how manufacturing works and how information moves through it.

A plant structure model. Enterprise → Site → Area → Work Center → Work Unit.

With a consistent hierarchy, concepts like access control, scheduling, and performance reporting all have a clear shape to hang off. Even a simple term like “line” can mean the same thing when different teams use it.

A definition of the information flowing between levels. The production schedule and production definition flow from the enterprise level down to operations. Production performance and capability flow back up.

Defining what gets exchanged makes integration a clearer design question, rather than an argument about terminology and responsibilities.

A shared language for IT and OT. This may be the most underrated benefit.

IT and operations often see the same plant from different angles, with terms and structures that do not always line up. ISA-95 gives both sides one shared model for talking about the same process, equipment, and information.

In short, ISA-95 does not tell you which product to buy. It helps you understand which parts have to exist, how those parts relate, and what information needs to flow between them.

The companion standard: ISA-88

ISA-95’s natural counterpart is ISA-88, the standard widely used to model and manage batch processes.

Where ISA-95 explains the structure and activities of manufacturing, ISA-88 focuses on how a process or production recipe is modelled: procedures, unit procedures, operations, and phases.

The key idea is separating the process from the equipment.

The master recipe describes what has to be done. The equipment model describes what equipment is available and what it is capable of.

With that separation, a change to the recipe does not have to change the equipment model, and vice versa.

At the MES layer, that concept can be applied through specifications acting as master recipes. Those are then composed into a routing that describes the complete production flow, whether linear, parallel, or with rework looping back to an earlier step.

Where VECHR MES sits

VECHR MES sits at Level 3, Manufacturing Operations Management, as the link between business planning and execution on the shop floor.

• Upward, VECHR integrates with Level 4 ERP to receive the production plan and return the real result: quantities, status, and production performance.
• Downward, VECHR connects to SCADA, PLCs, and equipment over OPC UA, MQTT, and Modbus TCP to get data from the process currently running.

VECHR’s plant structure model follows the ISA-95 concept, from plants and nested areas through work centers to resources.

On the process side, the specification and routing model follows ISA-88 principles. Version control means a process change can be managed without disrupting production orders already in flight.

This approach also means VECHR does not need to replace the systems that are already part of the plant. ERP, SCADA, PLCs, and equipment all keep doing their own jobs.

VECHR fills the Level 3 layer between them, connecting the plan, the process, the equipment, the materials, and the production result in one shared context.