The concept of Manufacturing Execution Systems (MES) was established by Boston-based AMR Research Inc. (www.amrresearch.com) in 1992 as the execution layer of manufacturing applications, which exists between the enterprise and control system to provide this visibility and control functionality. A later definition came in 1997 from MESA International (www.mesa.org), which stated, “Manufacturing Execution Systems deliver information that enables the optimization of production activities from order launch to finished goods.”
Today, this definition is still a good, practical definition of what MES is. However, more detail is needed in order to define and implement industry-specific MES solutions.
The ISA-95 standard separates the enterprise application functionality into three identifiable layers. The top layer is referred to as Business Planning and Logistics, which handles the supplier and customer-facing applications and the internal business level functions related to resource planning, product life cycle management, financials, inventory management and logistics.
The bottom layer of functionality applies to the specific process control activities related to batch, continuous and discrete control. This is the layer of control that is responsible for the physical control of the machinery and manual processes used for manufacturing.
Manufacturing operation management is the middle ground between the two other functional layers and is the modern equivalent of MES. This standard provides a clear picture of the various functional activities and high-level information flows found within manufacturing operations management in enough detail to define and implement MES solutions.
MES or manufacturing operations management, as defined by the ANSI/ISA standard, includes four major categories of manufacturing activities—production operation management, maintenance operations management, quality operations management and inventory operations management. In addition, the standard defines other activities that are used to support all of the major activities categories, such as management of security configuration, information, documentation and regulatory compliance.
The modular components from which MES applications can be assembled consist of the top-level interfaces to the business and logistic systems, and the interfaces that exist between MES and the manufacturing process level systems.
In addition to the interfaces, there are eight activities common to all major categories of manufacturing operations, as defined by ISA-95. These activities include definition management, resource management, detailed scheduling, dispatching, execution management, data collection, analysis and tracking. Automation, MES and Enterprise Resource Planning (ERP) companies that are supporting the ISA-95 standard understand this model, and many are using it to define their MES solutions in terms of the standard to better match user needs.
There are currently more than 40 global manufacturing companies spanning many industries that are using the standard to define and implement their MES solutions. The list includes energy, discrete manufacturing, life sciences, food and beverage, consumer goods, paper and chemical companies. Many have found that the time required to define their MES requirements and match their needs to solutions providers has been drastically reduced from several months to four to six weeks by using the standard as a framework for requirements definition.
If you would like to get involved in the work of the committee as it continues to define the standard, please contact the author.