A Manufacturing Execution System (MES) is a software application or suite of applications used to manage, monitor, and track production activities within a manufacturing facility. In the ISA‑95 model, MES typically operates at Level 3, between enterprise business systems and shop‑floor control systems.
MES systems collect and use real-time and historical production data from equipment, operators, and other systems to coordinate and record manufacturing operations. Common MES functions include:
- Dispatching and sequencing production orders to specific equipment or work centers
- Tracking work-in-progress (WIP), including lot, batch, and unit genealogy
- Capturing production events such as start, stop, downtime, and changeovers
- Recording material consumption, yields, scrap, and rework
- Managing electronic work instructions, recipes, and routings
- Recording operator actions, labor time, and resource utilization
- Collecting quality-related data such as measurements, test results, and checks
- Maintaining electronic production records, such as batch records or device history records
MES often interfaces upward with enterprise systems such as ERP for order, material, and master data exchange, and downward with shop-floor automation such as SCADA, PLCs, and DCS for equipment and process data. Within ISA‑95, MES functionality is described using standardized models for production, quality, maintenance, and inventory operations.