Manufacturing execution systems (MES)  are computerized systems used in manufacturing, to track and document the transformation of raw materials to finished goods. MES software provides information that helps manufacturing decision makers understand how current conditions on the plant floor can be optimized to improve production output. Manufacturing execution solutions work in real time to enable the control of multiple elements of the production process (e.g. inputs, personnel, machines and support services).

The idea of  Execution System might be seen as an intermediate step between, on the one hand, an enterprise resource planning (ERP) system, and a supervisory control and data acquisition (SCADA) or process control system on the other; although historically, exact boundaries have fluctuated. Industry groups such as MESA International— Manufacturing Enterprise Solutions Association were created in the early 1990s in order to address the complexity, and advise on execution, of MES Systems.

Manufacturing execution software comes with a whole bunch of concepts and terms that help provide a better understanding of what they actually are. Here are some of the more common terms and concepts associated with MES:

• Enterprise resource planning (ERP) system— strategic business process management tools that integrate all facets of an enterprise into one comprehensive information system that can be accessed by individuals across an entire organization.
• MESA-11— published in 1997, this model — created by the Manufacturing Enterprise Solutions Association (MESA)— indicated the 11 core functions of a standard MES.
• ANSI/ISA-95 standard — created for global manufacturers by the International Society of Automation, this is a standard set of guidelines for developers to follow when creating software that automatically links enterprise systems—like ERP—and control systems.
• Overall equipment effectiveness (OEE) — a general unit of measure that evaluates how well a machine works compared to its full potential.
• Supervisory Control and Data Acquisition (SCADA) — a system of software and hardware elements that allows manufacturers to maintain efficiency, process data for smarter decisions, and communicate system issues to help reduce downtime.

Core MES Functionality

• Operations management. Offer employees a global view of planned production orders and their production routing.
  
• Dispatching production units. Manage the bidirectional flow of production data in real time between the ERP and the workshop. This ensures production data is always accurate, consistent, and up to date.
• Product tracking and genealogy. Group final parts or batches with all their corresponding manufacturing data—from the raw material to the component assembly. This data is especially useful for manufa
• Labor management. Manages people, products, and/or operations and track any skills or authorizations they require.
  
• Quality management. Manages the quality of manufacturing process and units. This function can be integrated directly into the Manufacturing execution system software or can use external software.
• Maintenance management. More easily and accurately plans preventative machine maintenance to reduce downtime and production interruptions.
• Data collection and acquisition. Tracks and gathers essential data and easily recall that data when needed.
• Process management. Provides process routing and operational sequencing—including full production traceability.
• Performance analysis. Consolidates data to calculate key performance indicators (KPIs) like rework, scrap, process capability, OEE, and more.
  
• Document control. Provides a simple way for operators to access important documents—including instructions, drawings, notes, and more—when they need them.
  
• Resource allocation and status. Defines and tracks the status of resources and how they are used in the production process.