When plant floor managers, equipment providers and corporate executives debate the issues, there’s a fair chance that they will have some problems understanding the terms each of them uses to describe the ultimate flow of production.
As these plans develop, a growing number of companies are eliminating these communication problems by defining their user requirements with terms established by the ISA-95 standard, promulgated by the Instrumentation, Systems and Automation Society. That standard also provides Unified Modeling Language (UML)-based information models that can be used to build standard interfaces between enterprise resource planning (ERP) and manufacturing execution systems (MES). Additionally, it can be used to select MES suppliers and create MES systems and databases, among other tasks.
After a decade of ongoing development, the standard is making life simpler for those who must talk to many different groups as plants evolve. “ISA-95 helps in both design and implementation when you can verbalize how the system will be built. In the past, people had many different definitions for work cells, units of operation and many other terms,” says Kirby Powell, director of MES systems at Kline Process Systems, a process control system integrator based in
As the standard continues to evolve, it is adding more terminology and extending into several new areas. Members from new industries, including automotive and aerospace, are joining the standards committees, and developers are forging links with groups responsible for several related manufacturing standards.
Out to lunch
That’s a lot of effort for a standard that’s got far less awareness than its usage suggests. Kline Process is a case in point. The system integrator has been using the standard for a few years, with plans to continue expanding usage. But Powell and his counterparts don’t typically make a big deal out of its usage. When they do mention it, many end-users start thinking about lunch.
“Most of the smaller customers have heard of ISA-95 and know standards are good, but they have no idea of what value it brings,” Powell says. Most software providers are now beginning to follow the standards, making integration simpler, he adds.
Even equipment vendors who have been employing the standard for years say that only their largest customers are starting to understand the role the standard plays. “We’re finally getting to the point now where people understand the benefits, but they’re not necessarily known to all,” says
This lack of understanding doesn’t bother the developers of the standard. They are bullish about the adoption throughout the industry, whether end-users know they’re using it or not. “This is a very exciting time for the standard,” says J. Keith Unger, chair of the SP95 committee that oversees ISA-95.
Industry trends seem to point to even greater use, as companies attempt to link all aspects of their businesses together. “One of the benefits is that it helps create a singular vision of what the MES should do for the manufacturing function and what information is needed for business applications like ERP,” Steidinger says.
No simple solutions
While awareness and usage of the standard are growing, observers note that industrial applications are extremely diverse, so users shouldn’t expect too much. Knowing the limitations of standards is as important as understanding the limitations of a technology or system component.
“There are often irrational expectations for standards. People think they’ll all be like the 110 volt outlet, but most won’t let you just take one application and plug it into another,” says Rick Bullotta, a vice president at SAP Research, in Palo Alto, Calif., who focuses on future manufacturing.
Though variations are often considered a potential problem, that’s not a major issue for the semantics of ISA-95. Most developers feel that adding a few terms is a necessity, not a negative, in manufacturing environments. SAP, the big Germany-based ERP vendor, makes extensive use of ISA-95 while acknowledging that it won’t ever offer the compatibility provided by some standards. “In our world, standards are best practices. When you look at ISA-95 today, every implementation is different, with extensions and customization,” Bullotta observes.
As with many standards, implementation takes longer at the outset, but substantial time savings come with later projects. That’s particularly true when older systems are being linked together. “If you have two legacy systems on either end of a line and you want to leverage ISA-95, you need to do two mappings. Without it, you only have to do one, but then you may have maintenance problems,” Bullotta says.
The number of variations in the standard seem likely to grow in the short term. That’s because the manufacturing technologies covered by the document are expanding. The standard has been used primarily in food production, packaging and other batch processes, but now it’s moving into discrete manufacturing.
“The standard is broadening its usability into discrete manufacturing sectors like automotive, aerospace and electronic printed circuit boards. We can broaden the appeal, and it makes our model content much richer,” says SP95 chair Unger, also the principal manufacturing consultant at integrator Stone Technologies Inc., in
That change comes as the Automotive Industry Action Group is working with the committee, providing insight into that industry’s needs. At the same time, petroleum industry groups are also joining in the effort, adding continuous manufacturing to the mix.
This broadened effort will benefit from a recent gift from IBM Corp.,
These tools may also help move the standard forward. Some users would like it to take a broader approach. As globalization continues, the need for terminology that addresses enterprises instead of individual facilities is growing. “One of the biggest challenges for ISA-95 is to get outside the singular plant view,” says Siemens’ Steidinger.
As ISA-95 broadens its coverage, developers are also making sure it meshes well with other standards. The standard’s development committee is one of the members of the Manufacturing Interoperability Guideline Working Group, which includes the Machinery Information Management Open Systems Alliance (MIMOSA), Open Applications Group, the OPC Foundation, and WBF (previously World Batch Forum).
Members of the Working Group aim to make sure that when one of these standards talks to another, there’s a good chance that they will offer some compatibility. They also hope that their joint effort will lead to the creation of tools that help integrators and users build systems that include components that use the broad technologies covered by these standards.
Members note that the collaboration with other groups should provide substantial benefits for all parties. “This has made vendors and standards people extend themselves outside their comfort zones. The industry is better off because of that,” says Jay Jeffreys, marketing director for Third Party Programs at Wonderware, a
However, the interoperability between various standards won’t happen overnight. There are solid legacy programs, and each of these standards and implementations all have incompatibilities within the guidance of these standards. Providing links between standards is daunting task. The obstacles aren’t technical, they’re organizations, cultures and people,” Bullotta says.
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