The ISA-95 ERP MES boundary is the conceptual and integration boundary between enterprise business planning systems, commonly ERP, and manufacturing operations systems, commonly MES or MOM. In ISA-95 terms, it is usually associated with the separation between Level 4 business planning and logistics functions and Level 3 manufacturing operations management functions.
This boundary helps define which system is responsible for which data and decisions. ERP commonly manages areas such as orders, finance, high-level planning, purchasing, and enterprise inventory. MES commonly manages shop-floor execution, dispatching, production tracking, labor and equipment context, quality data collection, and work-in-process traceability.
In integration work, the boundary is used to structure data exchanges such as production schedules, material definitions, inventory status, equipment or personnel information, production results, and quality outcomes. It is not a requirement that ERP and MES be separate products, and it is not the same as a network security perimeter, although security and access controls may be applied at the interfaces.
The term is commonly used in system architecture, data mapping, MES implementation, ERP integration, and digital thread discussions. It should not be confused with the boundary between MES and control systems such as SCADA, PLCs, or DCS, which is typically closer to ISA-95 Level 2 and Level 3 interactions.