The world is a batch

ISA 88 gives process automation a native language for batch processes, and much more. Editor in Chief Walt Boyes reports on the state of the batch in the September cover story for CONTROL magazine.

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Batch ProcessingBy Walt Boyes, Editor in Chief

 

A Short History of the World…of Batch
“Batch manufacturing has been around for a long time,” says Lynn Craig, batch guru and Process Automation Hall of Fame inductee. “Most societies since prehistoric times have found a way to make beer.” That’s a batch process. It’s one of the oldest batch processes. Food processing and the making of poultices and simples (early pharmaceutical manufacturing) are so old that there is no record of who did it first.

“The process consisted of putting the right stuff in the pot, and then keeping the pot just warm enough, without letting it get too warm. Without control, beer can happen, but don’t count on it. Ten years ago, or a little more,” Craig continues, “batch was a process that generally speaking didn’t have a whole lot of instrumentation and control, and all of the procedures were done manually. It just didn’t fit into the high tech world.”

In many cases, the way food is manufactured, and the way pharmaceuticals and nutraceuticals are made, differs hardly at all from the way they were made 100 years ago. In fact, this is true of many processes in many different industries.

What is different since the publication of the ISA S88 batch standard is that there’s now a language and a way of describing batch processes, so they can be repeated precisely and reliably, anywhere in the world.

The S88 model describes any process (including continuous processes) in terms of levels or blocks (See Figure 1 below). This is similar to the ISO’s Computer Integrated Manufacturing (CIM) standard, which uses a set of building blocks that conceptually allow any process to be clearly elaborated.

FIGURE 1: COMPARING STANDARDS MODELS
ISA S88.01 Model
ISA’s S88.01 model is similar to the ISO’s CIM model com. (Click image to view an enlarged PDF).

The highest three levels, Enterprise, Site and Area, aren’t, strictly speaking, controlled by the batch standard, but are included to explain how the batch standard’s language can interface with the business systems of the area, plant site, and business enterprise as a whole. The Enterprise is a common term for a complete business entity, while a Site is whatever the Enterprise defines it to be. A site is commonly a place where production occurs.

The second edition of Tom Fisher’s seminal book on the batch standard, Batch Control Systems, which was completely rewritten after Fisher’s death by William Hawkins, states that, “Areas are really political subdivisions of a plant, whose borders are subject to the whims of management…and so it (the area) joins Site and Enterprise as parts of the physical model that are defined by management, and not by control engineers.”

The next two levels, Process Cell and Unit, are the building blocks of the manufacturing process. Process Cell is used in a way intentionally similar to the widely used discrete manufacturing cell concept. One or more Units are contained in a Process Cell. A Unit is a collection or set of controlled equipment, such as a reactor vessel and the ancillary equipment necessary to operate it.

Within the Unit are the Equipment Module and the Control Module. The Equipment Module is the border around a minor group of equipment with a process function. An Equipment Module may contain Control Module(s) and even subsidiary Equipment Modules.

The Control Module contains the equipment and systems that perform the actual control of the process.

Since the introduction of the S88 batch standard, every major supplier of automation equipment and software has introduced hardware and software designed to work in accordance with the standard. Many of those suppliers are corporate members of WBF, which formerly was known as World Batch Forum (See Figure 2 below). WBF was founded by Michael Saucier, then at Honeywell, as a way to promulgate the use of the S88 standards worldwide. (See the sidebar accompanying this story for an interview with Maurice Wilkins, WBF’s chairman, and Lynn Craig, WBF’s director.

FIGURE 2: GETTING PHYSICAL
S88 Physical Model
S88 physical model. (Click image to view an enlarged PDF).

A Batch of Batteries
EaglePicher Technologies, in Joplin, Mo., is a manufacturer of battery technologies for defense, aerospace and commercial uses. Bruce Henne, an engineer at EaglePicher, uses Rockwell’s Batch and eProcedure software to control the batch processes he uses to make batteries and power supplies.

“We have a variety of operations,” Henne says, “from highly meticulous discrete processes that are entirely manual, to those that are ‘automatic’ but designed to have an operator in attendance 24 hours a day. Each of these operations is low volume, and that low volume and intense guidance equals both higher quality and good production.”

Henne uses the batch software for all of his processes. “I like the fact that I can use the same software for the whole gamut from our manual processes to our automated systems.”

Because much of EaglePicher’s output is destined for military and aerospace applications, its batch software needed to be robust, reliable, and able to be acceptable to the U.S. Department of Defense for its “track and trace” program. “There’s no tolerance for risk in the product,” Henne says.

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