Plant execution software systems have many different scopes, forms, and formats, and they mean different things to different folks. Although plant execution software is used widely in a number of industries, it is rarely described similarly, and its functions are hardly ever identical.
An execution system used at an electronics discrete manufacturing facility is similar only in concept to one used at a food processing plant, and these differ substantially from that used by a pharmaceutical or chemical manufacturer. Time and experience have led the most successful vendors to pursue a “narrow-and-deep” strategy, and to devote their software development to the industries they know best. Even still, the names given to the various components of the execution systems vary greatly among industries and even among companies within an industry—if not between plants within a company.
To add further confusion, official definitions of a manufacturing execution system (MES) differ as well. APICS Dictionary (11th edition) defines it as
[p]rograms and systems that participate in shop floor control, including programmed logic controllers and process control computers for direct and supervisory control of manufacturing equipment; process information systems that gather historical performance information, then generate reports; graphical displays; and alarms that inform operations personnel what is going on in the plant currently and a very short history into the past. Quality control information is also gathered and a laboratory information management system [LIMS—applications used to manage the collection of samples, collection and formatting of test results, and the reporting of results by sample or product category, whereas these applications may be environmental-, medical- or research-focused] may be part of this configuration to tie process conditions to the quality data that are generated. Thereby, cause-and-effect relationships can be determined. The quality data at times affect the control parameters that are used to meet product specifications either dynamically or off line. [italics added]
Gartner’s IT Glossary defines MES as a
computerized system that formalizes production methods and procedures within the manufacturing environment, providing online tools to execute work orders. The term is generally used to encompass any manufacturing system not already classified in the enterprise resource planning (ERP) or open control system [OCS—a manufacturing system that is based on a set of commercially available, standards-based technologies, and that permits the open exchange of process data with plant systems and business systems throughout a manufacturing enterprise, whereas "control" refers to process control for discrete, batch, and continuous-process manufacturing, as well as computer numerical control and other motion controls] categories. In the broadest definition, MESs include computerized maintenance management systems (CMMSs), LIMSs, shop floor controls (SFC—a system of computers and controllers used to schedule, dispatch and track the progress of work orders through manufacturing based on defined routings), statistical process control [SPC] systems, quality control systems, and specialized applications such as batch reporting and control. [italics added]
What these lengthy definitions illustrate is that it can be difficult to easily identify or define the full range of applications used on the plant floor, let alone determine what falls exclusively under MES. Moreover, vendors never hesitate to add to the confusion by using creative labeling to suggest difference.
To put MES into perspective, it can be defined both broadly and specifically. Broadly speaking, MES can be regarded as a collection of business processes that provide event-by-event, real-time execution of planned production requirements. For example, it can calculate what and how much to produce, based on information from the enterprise planning level. From electronic production management systems to shop floor data capture, MES functions manage operations from point of order release to manufacturing, to point of product delivery to finished goods.
A narrow definition of MES is that it serves as a work order–driven, work-in-process (WIP) tracking system that manages and monitors production events and reporting activities. It captures “live” information about setups, run times, throughput, yields, etc., allowing managers to better measure constraints, identify bottlenecks, and get a better understanding of capacity. It closes the loop for production management and helps ensure production is followed as planned.
MES Today
Seen as a bridge from the plant floor to the rest of the enterprise, MES has become the principal means of delivering real-time order status to the supply chain, for available-to-promise (ATP) processing, and for “closing the loop” with sophisticated enterprise and supply chain planning systems.
An execution system used at an electronics discrete manufacturing facility is similar only in concept to one used at a food processing plant, and these differ substantially from that used by a pharmaceutical or chemical manufacturer. Time and experience have led the most successful vendors to pursue a “narrow-and-deep” strategy, and to devote their software development to the industries they know best. Even still, the names given to the various components of the execution systems vary greatly among industries and even among companies within an industry—if not between plants within a company.
To add further confusion, official definitions of a manufacturing execution system (MES) differ as well. APICS Dictionary (11th edition) defines it as
[p]rograms and systems that participate in shop floor control, including programmed logic controllers and process control computers for direct and supervisory control of manufacturing equipment; process information systems that gather historical performance information, then generate reports; graphical displays; and alarms that inform operations personnel what is going on in the plant currently and a very short history into the past. Quality control information is also gathered and a laboratory information management system [LIMS—applications used to manage the collection of samples, collection and formatting of test results, and the reporting of results by sample or product category, whereas these applications may be environmental-, medical- or research-focused] may be part of this configuration to tie process conditions to the quality data that are generated. Thereby, cause-and-effect relationships can be determined. The quality data at times affect the control parameters that are used to meet product specifications either dynamically or off line. [italics added]
Gartner’s IT Glossary defines MES as a
computerized system that formalizes production methods and procedures within the manufacturing environment, providing online tools to execute work orders. The term is generally used to encompass any manufacturing system not already classified in the enterprise resource planning (ERP) or open control system [OCS—a manufacturing system that is based on a set of commercially available, standards-based technologies, and that permits the open exchange of process data with plant systems and business systems throughout a manufacturing enterprise, whereas "control" refers to process control for discrete, batch, and continuous-process manufacturing, as well as computer numerical control and other motion controls] categories. In the broadest definition, MESs include computerized maintenance management systems (CMMSs), LIMSs, shop floor controls (SFC—a system of computers and controllers used to schedule, dispatch and track the progress of work orders through manufacturing based on defined routings), statistical process control [SPC] systems, quality control systems, and specialized applications such as batch reporting and control. [italics added]
What these lengthy definitions illustrate is that it can be difficult to easily identify or define the full range of applications used on the plant floor, let alone determine what falls exclusively under MES. Moreover, vendors never hesitate to add to the confusion by using creative labeling to suggest difference.
To put MES into perspective, it can be defined both broadly and specifically. Broadly speaking, MES can be regarded as a collection of business processes that provide event-by-event, real-time execution of planned production requirements. For example, it can calculate what and how much to produce, based on information from the enterprise planning level. From electronic production management systems to shop floor data capture, MES functions manage operations from point of order release to manufacturing, to point of product delivery to finished goods.
A narrow definition of MES is that it serves as a work order–driven, work-in-process (WIP) tracking system that manages and monitors production events and reporting activities. It captures “live” information about setups, run times, throughput, yields, etc., allowing managers to better measure constraints, identify bottlenecks, and get a better understanding of capacity. It closes the loop for production management and helps ensure production is followed as planned.
MES Today
Seen as a bridge from the plant floor to the rest of the enterprise, MES has become the principal means of delivering real-time order status to the supply chain, for available-to-promise (ATP) processing, and for “closing the loop” with sophisticated enterprise and supply chain planning systems.
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