Batch control: What do you mean?

Practitioners of control engineering generally like things spelled out when they can get it, and those revising the ISA batch control standard believe their three-year revision clarifies quite a bit. And, they say, the standard continues to become more usable for applications outside of batch control.
By Mark T. Hoske, editor in chief, mhoske@reedbusiness.com November 1, 2009

Practitioners of control engineering generally like things spelled out when they can get it, and those revising the ISA batch control standard believe their three-year revision clarifies quite a bit. And, they say, the standard continues to become more usable for applications outside of batch control.

ISA88.01 Batch Control Part 1: Models and Terminology, originally passed in 1995, started revision mid-2006, went out for vote last month, and may be final by early 2010. Clarifications addressed drafting errors in the original standard and less-than-specific wording that left too much to interpretation. Discussions revisited the standard’s original intent, and what it’s come to mean, as new technologies developed and were applied, bringing life to ISA88 concepts.

No academic exercise, the debate reflected a microcosm of real-world circumstances and incorporated input from industries outside batch control. Users, system integrators, and vendors augment efficiency by integrating batch control with continuous control and discrete control. Real lifecycle savings result, as high as 50% by some estimates. When systems are based on standards and integrate in a standard way, they can be more easily modified, upgraded, and replaced. Using a standard such as ISA88 avoids creation of a block of impenetrable automation, nearly impossible to maintain or adapt. Manufacturing needs flexibility, scalability, and adaptability, and the enhanced ISA88 concepts can help provide that.

ISA88 creates models and common terms, in four parts approved by ANSI/ISA and IEC, to understand the real world of controls, equipment, processes, and information management. Standard designs can be changed more quickly and easily. Since engineering can be creative as everyone seeks a better way, the trick is to be flexible enough in the models to allow upgrades, and even integration of adjacent dissimilar systems, with less effort.

There’s still room for creativity. Standards rarely guarantee interoperability, as anyone trying to get one vendor’s ISA88-based software to work with other software well knows. Still, this ISA88 Part 1 update narrows the latitude for interpretation and has a compliance clause to help create greater efficiencies.