The ERP MES boundary is the functional and data boundary between an enterprise resource planning system and a manufacturing execution system. It defines which system owns which business processes, records, and transactions as work moves from planning into production execution and back into business reporting.
In manufacturing, ERP commonly handles enterprise-level functions such as customer orders, finance, purchasing, inventory valuation, material requirements planning, and high-level production orders. MES commonly handles execution-level functions such as dispatching work, operator instructions, labor and machine activity, production status, quality checks, nonconformance capture, genealogy, and traceability.
The boundary is not usually a hard technical wall. It is an agreed integration point. Typical handoffs include sending released work orders, routings, items, bills of material, and due dates from ERP to MES, then returning completions, consumption, scrap, quality results, and production status from MES to ERP.
The ERP MES boundary should not be confused with a vendor product boundary. Some software suites include both ERP-like and MES-like modules, but the operational question remains the same: which system is the authoritative source for each process and data element. ISA-95 is commonly used as a reference model for describing this separation between business planning and manufacturing operations management.