Having taught MES applications for over 15 years let me share my knowledge with you how they will help in your industrial plants or processes. What do you really need to know and how will it help you be more efficient and competitive?
Manufacturing Execution Systems (MES) are systems that do relative real time calculations of your plant metrics to allow you to make decisions about your process or plant while it is running. They sit above operational systems and below enterprise resource planning and allow you to handle down time (delay accounting), monitor and reject product quality and much more.
What do you need to know about MES?
- What is MES?
- Brief History
- MES Hierarchy
- MES Standards
- ISA-88
- ISA-95
- MES Core Functions
- Production process management
- Production planning and scheduling
- Production evaluation
- Downtime management
- Quality process management
- Material traceability
- Document Control
- Dispatching production Units
- Labor management
- Key Performance Indicators
- OEE
- MES Integration
- IoT
- ERP
- PLC and SCADA
- Cyber Security
- Resources
- MESA
- ISA.org
- Software Solutions
- AVEVA MES
- AVEVA
Now that you understand what is involved in MES, let me explain what you actually need to know to improve the performance of your plant or process.
What does a Manufacturing Execution System Do?
Manufacturing Execution Systems (MES) are software tools that allows plants and processes to look at how they monitor their plants performance in relatively real time. It allows you to make quicker decisions in your business to increase performance, increase quality and reduce downtime. There are plenty of other things an MES system can do like material tracking and handling managing your whole business industrial processes as well as much more. It allows plants and processes to look at how they monitor their plants performance in relatively real time.
MESA (Manufacturing Execution System Association) the global non-profit organisation that looks at creating a community and training around the MES standards that are part of the International Society for Automation (ISA). They look after presenting a standardized definition of MES according to the 11 key MES functions we will discuss below.
MES is the basic technical means to implement an agile manufacturing strategy and achieve agile workshop productivity. It improves and optimizes the production management functions and increases visibility into the manufacturing process.
What is the purpose of MES?
MES optimises plant or process performance while it is running instead of after the fact like a typical reporting system. By monitoring the plan live you can fix or tune the plant or process to resolve minor issues before they escalate and cause break downs, poor quality product or product waste.
What is the difference between MES and ERP?
A MES system manages improving plants or processes at the industrial level and provides analytics like best crew on best shift, dollars or power consumption per widget or tonne. At the Enterprise Resource Planning (ERP) level runs the business and has functions like Accounting, HR and Sales.
NOTE: The ERP sits above the MES level as per the MES Hierarchy below.
How Does The Manufacturing Execution System Work?
An MES system collects data and provides relatively real time analytics on just how that plant or process is running. Typical key performance indicators are to the performance of the plant or process, the availability of equipment and the quality or the output as well as measuring consumables and waste.
Brief History Of MES Software
Advancement in mainframe computers in the 1950s and 60’s gave manufacturers the ability to capture, manipulate, share information and automate calculations and analysis in order to support the design of increasingly complex systems.
The focus shifted in the 1970s to Material Requirements Planning (MRP) as the complexity of manufacturing operations increased. Material requirements planning is a production planning, scheduling, and inventory control system used to manage manufacturing processes.
Subsequently in the 1980s, the term Manufacturing Resources Planning (MRP) became popular. MRP II presented an extension of MRP functions to integrate all aspects of the planning and control of the personnel, materials and machines. It then expanded further to what is now known as ERP.
Enterprise Resource Planning (ERP) started in the early 1990s. An ERP system can be defined as an integrated information processing system supporting various business processes such as finance, distribution, human resources and manufacturing.
Initially this concept gained huge popularity among manufacturers, but as the scope of managed systems increased, the ERP system was not suitable for controlling activities on the shop floor level. For this purpose, a new tool of manufacturing management called MES “Manufacturing Execution Systems” was evolved and utilized during the 1990s.
There are more interpretations of MES depending on different manufacturing conditions, but the common characteristic to all is that an MES aims to provide an interface between an ERP system and shop floor controllers by supporting various “execution” activities such as scheduling, order release, quality control, and data acquisition.
MES capabilities have improved greatly since 1992 thanks to the advancements in technology in part to MESA over the last few years in promoting the use of MES. MESA has acted as a global forum for manufacturers and software vendors alike and provided training first in person and lately online. The organization also has helped the growth and adoption of the ISA-95 continuous process and ISA-88 batch international standards.
MES Hierarchy
The functional hierarchy model of the ISA-88 and ISA-95 standard is very similar. It demonstrates the different levels of your business from the process or plant up to the ERP.
Level 0 is where the physical plant or process equipment is located.
Level 1 is the actuators that cause movement in the plan like a valve opening and the sensors that monitor the movement. The sensors being the instrumentation that converts the digital and analog data from temperature, pressure, flow and movement into digital signals for higher levels.
Level 2 is normally considered the control layer where you see PLC and DCS systems that run the plant or process.
It is also where the Supervisory Control and Data Acquisition (SCADA) layer where your plant wide control and monitoring is done. It is also the data acquisition level to concentrate information to pass to higher levels. When you see the graphical screens in a control room this is what the SCADA systems are.
Level 3 is the Manufacturing Execution Systems that allow you to fine tune your plant and analyse downtime or delay accounting as well as look at plan Overall Equipment Effectiveness (OEE) and many other metrics. This is where you can analyse and find out where the bottlenecks in your plant are as well as the best crew on the best shift is and like metrics.
And finally, you have Level 4 which is the ERP where all the Logistics, Human Resources, Finance, Marketing and all other higher level business functions live.
The Automation Pyramid as put forth some companies and by Real Pars below is an adaption of the MES hierarchy and it splits the PLC/DCS level from the SCADA level and ignores the physical equipment in the plant at Level 0.
MES Standards
The International Society of Automation (ISA) is a professional association specializing in automation and control systems and develops international standards for the industry. It also provides training and certifying professionals as well as news and updates in a membership program.
ISA-88 and ISA-95 are two well accepted standards in industrial automation that provide a set of models considered as best engineering practice for manufacturing execution (MES) and business logistics.
Both standards do have overlap and the MES hierarchy is one of these areas as well as some of the KPIs that can be used for them.
ISA-88
The main goal of ISA-88 is the control of batch processes like cars that have distinct numbers. This is for all processes that change what they produce or where the plant does not need to produce 24 / 7.
ISA-95
ISA-95 is for continuous processes like mine sites and water treatment plants. Processes that don’t change what they produce and normally run 24/7 plants and processes.
What are MES Core Functions?
The MESA-11 standard is function-focused and identifies 11 principal MES functions to meet the needs of various manufacturing environments. From the standard the functions below are required for effective support of the production management process. Let’s have a brief look at each of them.
Resource Allocation And Control
The MES system should allow you to monitor resource allocation and control. These resources are required by your plant or process to control things such as machines, personnel, tools, documents, etc. The control system is responsible for the control of the plant and that means your PLCs and DCS as well as your SCADA systems. It is also responsible for making sure the equipment is set-up for production as well as providing real-time status and historical resource usage.
Dispatching Production
The functionality of managing the production flow through dispatching production to specific personnel or equipment lies within the control system and includes dispatching information such as jobs, orders, batches, etc. With this functionality the WIP (work in progress) can be controlled by managing buffers and rework processes.
Data Collection And Acquisition
Within the control system, the functionality of obtaining information from the production floor is crucial. This functionality includes both operational data as well as data associated with a certain process or machine.
Quality Management
The control system is responsible for providing quality-related data collected from manufacturing such as test results to enable product quality assurance. Additionally, the data collected from manufacturing can be used for analysis to identify issues, recommend actions, correlating symptoms to determine a problem cause. It often includes SPC (statistical process control) tracking, which is a statistical tool that reduces waste in the form of reworked and scrapped products.
Process Management
The functionality of monitoring production processes and providing operator support for corrections or in process improvements lies within the control system. It may include alarm functions for ensuring awareness of process deviations that are outside the acceptable tolerance.
Production Planning And Tracking
The control system contains the functionality of production planning and tracking, which includes keeping and providing production status. This may include for example resource allocation for a specific order, current production conditions and production exceptions such as rework. It also includes the functionality of recording production data related to a specific product, such as genealogy data and product path.
Performance Analysis
The data collected within the control system enable the functionality of real-time reporting on manufacturing operations. The reports can contain PKI results, such as utilization, cycle time, WIP levels and OEE (overall equipment efficiency).
Operations & Detailed Scheduling
To minimize production set-up time the control system includes the functionality of sequencing orders in the production schedule based on for example priority or product type.
Document Control
The document control functionality is controlling and maintaining records related to a specific production unit. The records may include drawings, SOPs (standard operating procedures), recipes and more. The document control activities also include distributing the records, by for example providing an operator with the correct instructions.
Labor Management
Within the control system some of the labor-related functionality such as time reporting, training and certification tracking. This functionality often collaborates with the resource allocation function to optimize the allocation of personnel based on for example competence.
Maintenance Management
The functionalities of maintenance management are partly contained in the control system. Within the control system the functionality of ensuring equipment availability is included. This is based on the scheduling of periodic and preventive maintenance work, which may lie within the control system. In the control system a history log is stored in the maintenance activities performed in the production.
Key Performance Indicators
OEE (Overall Equipment Effectiveness)
OEE is a hierarchy of metrics that focus on how effectively a manufacturing operation is utilized. The results are stated in a generic form that allows comparison between manufacturing units in differing areas of the process, organizations, machines, and industries.
Components of OEE
OEE breaks the performance of a manufacturing unit into three separate but measurable components: Availability, Performance and Quality.
Each component points to an aspect of the process that can be targeted for improvement. OEE may be applied to any individual work area, or rolled up to areas or Plant levels. This tool also allows for drilling down for very specific analysis such as a particular piece of equipment, staff shift or any of several other parameters.
It is very unlikely that any manufacturing process can run at 100% OEE. Many manufacturers benchmark their industry to set a challenging target; 80% is not uncommon for continuous processes and 65% for batch processes.
OEE Equation
The calculation formula for the OEE is
OEE = Availability × Performance × Quality
OEE measurement is also commonly used as a key performance indicator (KPI) in conjunction with manufacturing continuous improvement plans like Lean or Six Sigma to provide an indicator of success.
Continuous Improvement Plans
When we look at implementing an MES solution the software is only half of the solution and the other half is ensuring that the plant or process adopts a Continuous Improvement Methodology. If you are in the ERP you may be using something like Total Quality Management (TQM) which is all about customer satisfaction.
If you are in the process or plant then you would use an Industrial Methodology depending on whether you are batch or continuous process.
Lean is used if you are in a batch process. While this is not always true most of the time it is. Its goal is the reduction of inputs, consumables and waste to create a set amount of something from your process.
Six Sigma is used for getting rid of bottlenecks to maximise the throughput of the plant. If you were a mine for instance and the more you could pull out of the ground the more you could sell. This would be a good methodology for you.
MES Integration
IoT
The Internet of Things (IoT) is the concept of everything that is electrically powered to be controllable via the internet or similar large area network. Whether it is traffic lights or a city’s street lights to make smart cities or home electrical devices like air conditioners.
Connecting an Industrial MES system to an IoT system allows you to optimize smart city’s and whole housing estates air conditioning systems to avoid brownouts and black outs during the middle of summer.
ERP
ERP are the top end functions of the business and MES can provide them relative real time data to enable them to do their jobs more efficiently. From accounting and finance to warehouse management, inventory, sales, purchasing and reporting. The ability to provide them information quicker as the processes are running means you can make quicker decisions that will keep the business flexible and competitive.
Tasks such as scheduling of machines and ensuring traceability via batch management are all handled by MES software. MES allows manufacturers to connect manufacturing operations to the rest of the company.
MES feeds ERP with timely information for just in time manufacturing and production. It allows you to change production to meet customer orders and be flexible with their demands. It also allows the enterprise to handle issues with production or if different quality products are coming from a farm field or mine for instance.
PLC and SCADA
When we look at the role of a Programmable Logic Controller (PLC) in the MES technology stack its role is to run the plant 24/7. It provides the low level control and interlocks for how the plant is to run and to protect your assets and people. They provide the digital and analog data that is fed up to the Supervisory Control and Data Acquisition (SCADA) systems.
The SCADA systems provide the data to process Historians and from there to the MES systems to optimize your plants and processes. The SCADA systems provide supervisory control and the PLC’s provide actual control. While the MES systems provide the high level analysis and control.
Cyber Security
When you have so many systems interlinked from instrumentation to enterprise cyber security becomes a serious concern. From your hard wired instrumentation to telemetry that is linked to your PLC and SCADA systems.
To your site management and the internet WAN links across the internet to your enterprise on VPN links. With third party access like System Integrators and contractors there are lots of places to secure and with the threat of hackers and state based actors you need to minimise your risk.
You should have people inside your organisations that look at securing your assets and making your site harder to get into like steering wheel locks on cars. Don’t be the easy target. In industrial control you can look at training a staff member on ISA-99 or SANS ICS.
Obviously people that look after security like this should have a base knowledge in Cisco Networking certification or Hirschmann that are more mature in rack mounted network hardware.
Resources
MESA
Mesa is a not for profit collection of industry companies that helps develop that have banded together to help with education on MES as well as providing best practice and support for companies.
They run training courses around the world and have an online course as well for MES. Their training includes information on the ISA standards and has two levels of certification. I attended their early training when working for Schneider Electric when we hosted them in Australia.
ISA
The International Society for Automation organisation is the globally accepted best practice and standards body. They work to put in place training, certification and standards for the Automation Industry.
Software Solutions
AVEVA Production Management
https://www.aveva.com/en/products/production-management/
Initially created by Citect and then moved to Schneider Electric with an acquisition and finally to AVEVA with the reverse acquisition of AVEVA by Schneider Electric. The software was designed for all Industrial verticals as a total MES solution. Later rebranded to Mining with the acquisition of Wonderware MES that took on the Manufacturing industry vertical. Formerly known as AMPLA it is now known as AVEVA Production Management in a big rename of products by AVEVA at the start of 2020. This is a single integrated product.
AVEVA MES
https://sw.aveva.com/operate-and-optimise/batch-and-hybrid-process/manufacturing-execution-system
Formally known as Wonderware MES and now Aveva MES. This solution sits on top of Aveva System Platform (fna Wonderware System Platform). It pulls data from the Process Historian to precalculate your KPIs on the fly to help you make quicker decisions like all MES software. Its main industry is manufacturing. It is more a set of tools then one integrated product.
Siemens MES
https://www.plm.automation.siemens.com/global/en/products/manufacturing-operations-center/
Siemens is another well known company with an automation industry division. Up until now they only had a set of tools but have bundled this together into their new OpCenter offering. They mainly focus on Manufacturing Operations Management (MOM) and are not seen too much in other industries.
Rockwell MES
https://www.rockwellautomation.com/en-au/products/software/factorytalk/innovationsuite/mes.html
Rockwell more known for their programmable logic controllers (PLC’s) also has two software bundles in MES. The first is Production Management and the second is Quality Management. The Delay Accounting or Availability is handled in the Production Management. If you look at their website they are focusing on Life Sciences, Automotive, Consumer Packaged Goods and Metals. There is more information about what solutions they have in these areas on the link above.
Other MES Providers
There are many other players in the MES market and you can find a list of the providers at the link below.