Open, Modular Architecture Control (OMAC) Users Group was established in 1994 to produce consensus guidelines to improve flexibility, improve capability and reduce system integration costs in the development and implementation of open control technologies for manufacturing applications.
Process and Analytical Technology Initiative (PAT) is an effort by the U.S. Food and Drug Administration that encourages development and use of systems for analyzing and controlling manufacturing processes based on timely measurements of critical quality and performance attributes obtained during the processing of raw and in-process materials with the goal of ensuring end product quality.
Okay, now that we have some idea of the pieces, let’s examine how they fit together to improve plant-floor visibility; but first a word to the naysayers.
Too frequently people believe that their businesses and/or processes are unique and, therefore, not adaptable to standardized information integration solutions. They should heed Drucker’s advice to focus on the meaning of information, not the delivery mechanism. To illustrate his point, Figure 1 provides a graphical representation of what an integrated S88/S95 and B2MML schema solution provides. If you can see your company’s production-to-business-systems architecture fitting into this hierarchy, then the standards, templates and initiatives we’re discussing can:
- Increase your company’s process knowledge,
- Improve process and product quality, yield and throughput,
- Reduce production costs,
- Reduce equipment life-cycle costs.
If you’re still reading, chances are you believe S95 and B2MML could improve visibility into the bowels of your business. However, despite Figure 1’s insight into what S95 and B2MML bring to the solution, it does nothing to answer the question—why S88?
Applying the principles described in S88 becomes most beneficial if:
- You’re using the same equipment to produce entirely different products at different times,
- You need to track batch lots,
- Your customers require documented proof that your products meet pre-defined specifications,
- You need the ability to transfer product production to different facilities,
- You need the flexibility of assigning control system application support personnel (or contractors) to multiple systems, processes and sites.
Where fits into the system
A successful PAT implementation combines data from many sources in the control layer.
An examination of control system software developed pre-S88 usually reveals “spaghetti code.” Within spaghetti code, it’s often possible to see remnants of a rudimentary structure that either wasn’t well-understood by subsequent software developers and/or simply wasn’t robust enough to accommodate years of process-control changes by multiple users. In such situations, the physical control system frequently gets the blame when, in fact, the real culprit is how the control system’s application software was implemented to begin with.
S88, illustrated in Figure 2, is a independent consensus control system standard that defines in great detail a common terminology, as well as the physical and procedural hierarchy for recipe management and process segmentation. The application of S88 models encourages development and reuse of pretested software modules designed to match the capabilities of equipment and processing units.
Originally developed by a committee of process control experts working toward a universal batch process solution, S88 has since proven an equally effective automation development model for continuous (e.g., refineries), as well as discrete processes (e.g., fill-finish).
The wide-spread acceptance of S88 is revealed by an examination of the underpinnings of every major control system on the market today. Though each vendor has incorporated its own unique representation of the S88 models into its control system offerings, the differences are mostly cosmetic. This nearly universal implementation of S88 models across different manufacturers’ control system platforms provides end users with significant advantages.
- Control system engineers with a good understanding of S88 can efficiently apply their application expertise across different manufacturers control systems.
- Application solutions are designed to maximize the features and benefits of processing equipment, even if not all features and benefits are required for every product produced.
- Modules successfully developed, validated and applied at one site are easily shared with other sites, often with little or no re-validation efforts necessary.
- In-process production status is shared more easily and consistently with MES and other business systems.
This last bullet is the focus of this article.
Because S95 is designed to be S88-aware, the application of S88 terminology and models in developing the control system application software makes it much easier to provide business systems with information whose origin is, in S95 terms, Level 0,1,2 plant-floor and/or Level 3 MES systems. That’s not to say the benefits of S95 can’t be obtained without having implemented an S88-conformant application, but it does mean you probably won’t be able to take full, if any, advantage of pre-configured, pre-tested templates such as B2MML. It also means you’ll need to be much more diligent in maintaining and validating your custom implementation over time.