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This document will provide a high-level overview to help clarify what MES is and touch on surrounding areas that are often classified as MES.
Overall situation
Manufacturing execution systems, or MES software, are tools designed to help companies manage their manufacturing processes. Today, manufacturing is too complex without a system to define how customer orders are scheduled and manufactured on the production floor. If you're in manufacturing, and you have an MES, it's probably just in the form of spreadsheets, emails, and published schedules. Modern MES software helps replace these spreadsheets with a connected system that provides real-time operational information to those who need it, when it is needed, and allows data to flow directly from factory floor equipment and equipment to ERP and inventory management systems.
A manufacturing company has to manage materials, goods, money, people, and so on. These companies require systems from finance, purchasing, sales and more. All the way to the factory floor, where machine operators produce the right product at the right quality standard.
Inside the plant, these systems can be handled by computers and software, notepads, verbal communication, or by a person with years of experience. Whatever the system is, it has to be right, otherwise the manufacturer will go out of business due to missed shipments, mishandled finances, poor product quality, etc.
At the upper level, systems are often referred to as enterprise resource planning (ERP), manufacturing resource planning (MRP), or advanced planning systems (APS). These systems process orders from customers, group orders into production orders, ensure sufficient raw materials are on hand, schedule equipment to run production orders, and more.
At the bottom level, there are systems in place to control the machines. These systems include sensors, buttons, special-purpose computers that control machines, human-machine interfaces (HMIs), and more. Operators can start, stop and control other aspects of machine operation. These systems themselves have no knowledge of what products are being produced, what raw materials are being consumed, etc., require no manual input from the operator, and are not required for these systems to run the machines.
Typically, human-machine interfaces (HMIs) are local components of a machine or process and do not span the entire facility. This is where supervisory control and data acquisition (SCADA) comes into play, often (but not always) in the same system as human-machine interfaces (HMIs). SCADA systems control processes locally or remotely, provide advanced monitoring, collect process data in real time, maintain historical data, record events and alarms, and more.
Between the upper and lower tiers, each manufacturing company has a tier commonly referred to as the MES. The system is used to control, track and record the conversion process of raw materials to finished products in real time.
The main functions provided by the MES system include:
• Detailed resource scheduling and status
•Responsible for the scheduling and sequencing of production tasks
• Traceability and genealogy
• Work in process and inventory
•quality assurance
• Detailed maintenance management
• Work instructions and other document controls
• Performance analysis
Some of these items above are similar to what an ERP or MRP system provides, but the level of detail required by the plant is much greater than that required by the upper layers. For example, an ERP system does not require the details needed to replace a machine in order to run a particular product, nor does it require the steps of a process that precede the production of a particular product.
ERP systems are not real-time, nor are they designed to collect data volumes at the speed that MES, SCADA and HMIs systems must. Typically, when production is complete, the ERP system records details about the finished product, raw materials consumed, and more. MES systems can track production in seconds, and in some cases even less than a second.
This means that schedules, work in process, performance metrics, quality, and more are updated in real time rather than at the close of business.
ISA-95 definition
The ISA-95 standard was created because the integration of enterprise management systems with manufacturing systems is difficult and costly.
It provides a common term and model to describe controlling, tracking and recording the transformation of raw materials to finished goods.
ISA-95 uses the term Manufacturing Operations Management (MOM) to describe the space between the upper and lower levels.
Part of the ISA-95 standard specifies the content areas as: Production Operations Management, Maintenance Operations Management, Quality Operations Management, and Inventory Operations Management.
The ISA-95 standard provides a consistent operating model and terminology, which is the basis for providing communication flow between ERP , MES and SCADA systems.
PCS systems are designed to control processes and machines, but are not well suited for handling large volumes of production data. They can make control decisions in the 5ms to 200ms range, but have limited history storage and database capabilities. ERP systems tend to be more transaction-based and are great for handling finances, inventory, accounts receivable, and more. They process customer orders, check if additional raw materials should be ordered, pay suppliers, financial reports which can be updated at any time of the day, week, month, quarter or even year.
Between the PCS system and the ERP is the Manufacturing Execution System ( MES ), also known as Manufacturing Operations Management ( MOM ). In this era of manufacturing, most production data is still stored in proprietary systems that are not easily accessed or shared. Operations often rely on various documents (word, excel, WeChat, etc.), but what really needs to drive continuous improvement is a data-centric manufacturing information system that can provide real-time actionable information.
Production tasks and segments
ISA-95 provides the concept of segments to define any task that is done during the manufacturing process. All tasks require resources in terms of materials, equipment and personnel. For example a basic task (segment) of wine bottling that has three input resources (wine, bottling line 1 , and bottling operator ) and one output bottled wine .
If more details on batch traceability and/or production control are required, more resources can be added to the bottled wine segment task. Bottles , caps , and labels , all in the form of items, are added to this segment task. In addition, an inspector was added as a person. There is no limit to the number of resources that can be added to a segment.
Production may involve more than one task or segment. This is achieved by including multiple segments in the operation. Remember that segmentation is the basic task. We can now chain multiple segments into a single operation to execute, track and schedule more complex tasks.
How the operation segment uses the process segment and how the operation definition refers to the operation segment can refer to the ISA model diagram. Collectively, these are doing basic definitions. They are only created or modified when users define their production processes.
On the production side, operational responses and response segments are created when an operator starts production. Therefore, each production run will have a set of action responses and response segments.
device resources
Any automated production or processing requires equipment. Defining production tasks for each specific device is tedious. A better approach is to organize devices into categories or classes using ISA-95 terminology. Example: Consider five packing lines in a packing area, three of which can pack mixed nuts and the remaining two cannot. Create a mixed nuts device class that contains three lines that allow defining a task specifying that a mixed nuts device resource is required.
human Resources
Any production or processing may involve people. Personnel can be tracked and who can initiate a production control operation is supported. This person can be selected automatically by system rules, or by other methods.
MES Person objects are automatically generated from users who define the name system. This prevents the default "admin" user from being created in the MES system and showing up in the selection list. MES Person objects are synchronized when the system is first started, and every hour thereafter. They can also be synced on demand.
Defining production tasks for each specific person is very tedious. A better approach is to classify these people as specified by ISA-95. Example: Consider unloading vinegar at an unloading pumping station. If there are 10 operators that are eligible to unload vinegar, then creating a vinegar unload operator class that includes those 10 eligible operators will require only one unload vinegar task definition. Adding an 11th operator is as simple as adding that person to the vinegar uninstall operator class.
MES definition
The term MES is used by a wide range of audiences, making it difficult to agree on a single definition.
According to the description of ISA, MES is a subset of MOM in some states.
However, the general usage of the term MES actually includes more of what ISA defines in MOM.
More people tend to recognize the term MES than MOM, because MES was established many years before the ISA drafted the ISA-95 standard. Therefore, the ISA coined and defined the term MOM.
Given this situation, many suppliers state MES in their product names or use it to describe their products, as this may be a more effective marketing method for them.
In some companies studying MES, different types of functions are included in their MES definition. Some products include functions such as batch processing systems in the MES, while ISAs exclude them from the MOM.
This leaves us with a lot of confusion about "what is MES".
The safest approach is to define the MES as the MOM, since we can extend it to include additional functionality to support real-time control, tracking and documentation of the transformation of raw materials to finished products.
The MES system is not a workshop system, nor is it an ERP system. Manufacturing execution systems, or manufacturing operations management (MOM) software, are modeled after the ISA-95 standard and are designed to bridge executive-level communication between the factory floor and management. Most companies have had some success with standardizing all data at the MES layer. Ask yourself how your company currently handles MES data. Is there a separate SPC system, documented and tracked on paper, set up on a local operator interface, using Excel? Data from different sources can be confusing and systems not working together can cause a lot of frustration. The result is loss of money, time and quality. So what is missing here? The answer is a fully integrated unified MES solution that gives us all MES data in one place, on one screen.
MES operates across multiple functional areas, for example, product definition management across the product life cycle, resource scheduling, order fulfillment and scheduling, production analysis and downtime management for Overall Equipment Effectiveness (OEE), product quality, recording and tracking.
MES creates "as shipped" records, captures data, process and results of the manufacturing process, and maintains a system of record. This is especially important in regulated industries, such as food and beverage or pharmaceuticals, where documentation and proof of processes, events and actions may be required.
The concept of MES might be seen as an intermediate step between enterprise resource planning (ERP) systems and supervisory control and data acquisition (SCADA) or process control systems, although the exact boundary has historically fluctuated. Our MES solutions target the plant operations layer in manufacturing systems, providing a flexible approach to interact with ERP systems and plant equipment. According to the ISA-95 model, plant operations include production operations, inventory operations, quality operations, and maintenance (or engineering) operations.
MES is a factory floor execution system. In this layer, operators interact directly, step-by-step through the workflow of producing or repairing a product. The list of work to be performed, the specific instructions for performing the work, the data points to be collected, the quality checks of the work, and the sign off to indicate that the work is complete, are all carried out in this layer.
MES provides the workflow, visibility and event notification needed to ensure that manufacturing meets the information needs of the enterprise. At the same time, MES reduces non-value-added activities, improves data accuracy, and provides ERP systems with the real-time data needed to maximize enterprise processing, planning, and scheduling activities.
MES systems act as messengers between the factory floor, enterprise engineering (PLM) and enterprise planning/scheduling (ERP). When an operator needs data from ERP or PLM: the request is initiated within the MES; the MES system then connects to the appropriate system to retrieve and display the information.