MES and SAP sit at different layers of the manufacturing stack. MES orchestrates and records production on the shop floor in real time, while SAP (or similar ERP) plans and accounts for materials, orders, and finance. In regulated, brownfield plants they must coexist and be integrated; one rarely replaces the other without major risk and revalidation.

An MES can help standardize processes across sites by enforcing common master data, workflows, work instructions, and data collection rules on the shop floor. In practice, this only works if governance, change control, validation, and integrations are managed carefully. Brownfield plants, legacy systems, and local exceptions often limit how far standardization can be pushed.

ISO 22400 defines a standardized set of key performance indicators (KPIs) and terminology for manufacturing operations, especially around OEE and related metrics. Its main purpose is to create a common language so plants, systems, and stakeholders can measure and compare performance consistently, while recognizing that practical use still depends on data quality, integration, and validation.

To use ISO 22400 KPIs reliably, equipment state events need a consistent model: clear state definitions, single active state per resource, timestamped start/end, and traceable reasons for changes. In brownfield MES/SCADA landscapes this usually means normalizing vendor-specific states into an ISO 22400-aligned state model, with explicit handling of gaps, overlaps, and manual overrides.