01 November 2004
There's a kind of emergence
MES builds on process improvements.
By Ellen Fussell
There's a buzz in the air.
It's coming from work flows, manufacturing, instruction, and production tracking activities. It's also the hum of clients, vendors, and consultants talking about improvements in their manufacturing systems. The buzz could be related to the fact that lean manufacturing is a commonality in industry these days. It could have much to do with Six Sigma initiatives or process improvement initiatives. Whatever it is, manufacturers are looking for a system they can put in place to initiate and maintain improvements. And, as Cary, NC-based BRL Consulting president Dennis Brandl put it, the buzz signifies a "kind of emergence" of manufacturing execution systems (MESs).
As a result of this emergence, Brandl and others are seeing more written MES requirements. "A lot of companies are writing requirements and putting out requests for proposals for MES systems," Brandl said. "So I think we're seeing a resurgence of interest in these Level 3 systems or manufacturing control systems. More companies these days are using the ISA-95 Part 3 as the model for these requirement specifications.
The goal is to eliminate waste and non-value-added work, Brandl said. "In some industries you have paper-generated documentation that says how you're supposed to run your process. The hard thing is to get visibility of all the tasks you're doing in your manufacturing. So it's hard to find out which ones are value-added and non-value-added or wasted effort," he said. Manufacturing companies, especially pharmaceutical, chemical, biotech, and food and beverage, are looking at MES as a way to enable these efforts. It's what will direct the performance of work, people, and equipment to actually get work done.
The buzz about using the standard is especially growing among pharmaceutical companies, "who have a big push from the FDA to move to electronic records," Brandl said. "This standard is a way to write requirements for systems that will do that. It's the same with biotech companies." Food and beverage companies want it because they're pushing to lean manufacturing, "and this system allows them to hard-code the procedures they want to have followed and make sure they are followed," Brandl said.
SP95 is particularly useful in the pharmaceutical industry because of the industry's need for enterprise production management, said Em delaHostria, a manager in the advanced technology global standards and trade focus group at Rockwell in Mayfield Heights, Ohio. "The standard helps with the manufacturing execution part they need to actually do the production," he said. "They have R&D, the clinical trial phase, and the manufacturing-all that needs a lot of linkage with the automation and control systems on the plant floor. Within that context the manufacturing piece is what 95 has addressed; it allows that part of the production management to talk to the business office systems where you get the orders and purchase materials. And it translates all the ordering and requirements down to what has to be done to the equipment on the plant floor."
"What is really astonishing with ISA-95 is the speed of its adoption rate, which is now faster than its development," said Jean Vieille, a consultant and ISA SP95 member in Dompierre Les Tilleuls, France. "The first claims about ISA-95 compliance came from solution vendors, not always backed by an actual and extensive use of the standard concepts in their products. The recent rush comes from major final users who want to make full use of the standard and beyond. This is eventually leading vendors to actually orient their development to offer actual standard-related features, and new vendors to join."
Vieille said the ERP community hadn't heard much about ISA-95 until a few months ago, when the standard "consciousness finally crossed the chasm between execution and business communities with the recent jump of SAP." Yet the standard is still confined within process industries, he said. "Part 3 of the standard helped a lot to clarify the shop floor execution information management. It triggered the need to extend Parts 1 and 2 data models to other manufacturing operation domains beyond production domains (things like maintenance, quality, and inventory.)"
A lot of times manufacturers are doing control by paper, Brandl said. "When you get a request from business systems that says you have to make 50,000 widgets, that could take time. So you have to develop detailed production schedules to help you figure out how you'll actually meet that production request, using the material, equipment, and personnel you have. In such a detailed schedule, you might know at 5 you'll set up a bottling machine to bottle 2-liter bottles, and it'll run for two hours. A lot of times that's done by paper," he said. MES systems are computer systems that do this automatically. The advantage is repeatability. There's a consistency in the rules and procedures you want to follow. "When you have to trust people's memories to write stuff down, you have a lot of sources for errors," Brandl said.
The B2MML language, which proposes an XML implementation of Part 2, is the actual vehicle of the standard, Vieille said. "Developed outside official standardization bodies, it is more susceptible to catch up with the needs of the industry, which significantly relies on this privately developed specification. Every B2M project speaks WBF B2MML, then ISA-95, but never ANSI/ISA95.00.01 or IEC/ISO62264. The industry definitely needs more responsive standard construction processes and does not mind so much about national or international stamps," he said.
On the level
The ISA-95 Part 3 standard is a model for this Level 3 activity. It's a generic model independent of any specific manual. It defines the activities that go on in Level 3 in a standard way. So you can look at any factor and, using that model, determine the requirements you'd have for running your factory-so it becomes an outline for requirements specification.
The Level 3 systems include MES and laboratory information management systems (LIMS) that manage all the testing and recording of the testing in labs. It can also include maintenance management or asset management systems, "the systems used to track equipment and make sure you're performing the required maintenance on the equipment," Brandl said.
Lastly, there's the warehouse control system, which directs movement of materials manually through operators who drive forklift trucks to automated guided vehicles. Automated storage retrieval systems include robots moving materials-all at Level 3.
That Level 3 sits on top of Level 2, programmable logic controllers (PLCs), distributed control systems (DCSs), and automated guided vehicles (AGVs).
As part of the process documentation, Level 3 sits on top of the real-time control system directing the work and saying when it's time to turn on and off. "It's really more real-time in the human time frame than a control system frame," Brandl said.
In the ISA-95 standard, Level 4 is an enterprise resource planning (ERP) logistics system. "Here's where manufacturers make sure the right materials are delivered to the right factory at the right time," Brandl said. With Level 4, manufacturers can release production orders to the factory that give information on the materials they have to make. "It takes the production orders and tells you at what point in time you set up batches and run machines, how long, and which equipment you use," Brandl said.
Today, because ISA-95 is not fully finished and not many players have embraced the concepts, "people are wondering what we need to do next," delaHostria said. "Now we're seeing some of the players use the data models and apply in their own implementation. If you say they're SP95 compliant, that's stretching it too much. But a lot of their data object definitions (the structures of the data and how they ought to be passed around) are things that describe the capacity the plant ought to have to manufacture a certain medicine-95 has several definitions like Part 2. In Part 1, the data objects are a full set. Some of the implementations may not be using the full set. So eventually once you have a set of compliance tests, then people can gauge whether they are fully or partially compliant with 95," he said. "Everybody wants to use it in total, in its full glory. But like anything else, standards only have parts of them applied to certain situations."
Three Parts Integration
ISA-95 Part 1 defines the categories of information the business system should exchange with the manufacturing operations system. It defines four categories-product definition, production capability, production schedule, and production performance. Each of these four categories relies on four resources-personnel, equipment, materials, and process segment. Part 1 defines an equipment model to use as a basis for designing the plant objects. If you use object-oriented programming, the equipment objects shown in the equipment hierarchy can each be a class from which you can derive subclasses.
ISA-95 Part 2 further defines the attributes for each of the objects contained in the object models. Object models are software-independent and contain a description of the interface content-the data to be exchanged between the business system and the manufacturing operations system.
ISA-95 Part 3 focuses on activities within the manufacturing operations-Level 3. This part specifies a generic activity model that applies for different types of manufacturing operations such as production, maintenance, inventory, and quality. Part 3 does not intend to define how you should design a product. However, this part of the standard is excellent to use as a reference when discussing what functionalities the MES/MOS product covers. Some of the activities, such as scheduling or data collection might not be included in the MES/MOS product itself, but another product from the same company might cover them.
Who Benefits from ISA-95?
By Charlotta Johnsson
Almost anyone in some way connected to the control, automation, and manufacturing operations field can benefit from knowing the ISA-95 standard's content-vendors, end users, integrators, technicians, operators, managers, and chief executive officers (CEOs). As the title, "Enterprise-Control System Integration," indicates, the ISA-95 standard treats the topic of how you should integrate enterprise business systems with manufacturing and control systems.
Vendors, end users, and integrators can use the standard successfully. The standard isn't written explicitly for any of those groups, yet it contains help for vendors who are designing and structuring a product. It's also helpful for end users, structuring user requirements and comparing products from different vendors; and for integrators in understanding the user requirement specifications and selecting solutions.
You can divide industrial systems into different functional categories, depending on the focus. ISA-95 is based on the hierarchical structure presented in The Purdue Enterprise Reference Architecture. This hierarchy defines four different levels.
How can integrators, end users, and vendors benefit? Employees working at the business level-such as SAP, Baan, and JDE-can start to communicate with the manufacturing and control people. Traditionally the two groups have used different words for the same thing, or called the same thing different names, resulting in misunderstandings and unnecessary time delays and errors. Technicians, operators, managers, and CEOs can now better understand each other. And people from different companies now have a common set of terminologies to use when speaking with each other.
Vendors of business systems or manufacturing operations and execution systems can benefit when developing, marketing, and selling their product. ISA-95 provides a good understanding of the enterprise control systems integration issue as well as the MES/manufacturing operations systems (MOS) field. So it's a good knowledge base for each developer, system architect, and product manager. Developers should have access to the full description of the words they need in developing their products. Most MES/MOS products and business systems have a built-in model of the plant.
End users of business systems manufacturing operations and execution systems can benefit when buying, evaluating, and using a product. An automation project can consist of integrating a business or enterprise system with manufacturing operations systems. In such a project, one important task is to identify and define the scope of the enterprise and manufacturing operations you want to automate. The ISA-95 functional enterprise-control model can be a starting point to localize the functions and the data flows involved in the automation project. An end user has to compare the products of different vendors. The vendors present the capabilities and functionalities of their products in different ways. To get a good comparison and a good understanding of the different products, use the ISA-95 standard as a universal language to translate the presentation of a vendor into ISA-95 terminology and then compare.
Integrators are often involved when selecting a solution and when implementing the solution. They have to analyze the user requirement specification. The standard can help structure the integrator's work when selecting a solution for MES. The first task is to understand if the function the client is asking for belongs to the manufacturing operations domain or the enterprise system, or whether it involves both systems. Often an integrator is concerned with requirements that involve characteristics from production operations, maintenance operations, and quality operations as well as inventory operations.
Level 4 corresponds to the business planning and logistics, and this is where you'll find activities like plant production scheduling and operations management. Level 3 is the manufacturing operations and control level-production dispatching, detailed production scheduling, and reliability assurance. Levels 4 and 3 are similar independently from the type of industry in which they're used. Levels 2, 1, and 0 differ with respect to the type of industry-batch, continuous, and discrete.
Behind the byline
Charlotta Johnsson is in automatic control at the Lund Institute of Technology in Lund, Sweden.