The State of the Batch
ON AUGUST 15, 2006, Lynn Craig, of WBF (formerly the World Batch Forum) and a founding member of the SP88 Batch Standard Committee, and Maurice Wilkins, chairman of WBF, sat down with Control’s editor-in-chief Walt Boyes and talked candidly about the state of batch control and the batch standard.
Craig: We’re well past the tipping point. What we need to do now is bring a lot more people along, and we haven’t been terribly successful at it. WBF has, I think, provided a lot of information and help for people who want to understand. But we have entirely too many people out there in the industry who don’t understand the nuances of S88 yet.
Wilkins: S88 needs to get out to the other people it was intended to get out to, which include the process engineers and the plant engineers. It’s still seen as an automation kind of thing, and it needs to get out to the other guys who need to embrace it, too. Industry tends to see it as an automation thing, but it isn’t intended to be an automation thing. It sits in the automation environment, and it shouldn’t.
Craig: S88 is a beautiful, beautiful toy, and I call it that on purpose. It’s the kind of thing that management can understand, operations can understand, and process engineering can understand. It’s a tool for understanding amongst disparate groups. You have the modularity, so you can look at some grouping of equipment. You can talk about it. Everyone can understand what the other is saying. Too many of us in the automation world have been seen as the kind of geeks that speak a language that nobody understands, so “I don’t want to talk to them anyway.” This is a way to come out of the cave, and talk about how this process is going to run.
S88 defines a structure that can be used to understand most any manufacturing process, and can be applied to controlling and communicating about an awful lot of industry out there today.
I don’t think you can apply S88 to all discrete automation, but you certainly can apply it to a lot. You can also apply it, I think, to continuous. There’s a lot more to it that what’s written down in the standard. You have to interpret it for continuous process, but it’s very effective there. All it is doing is providing a structure to apply internally consistent procedural control to a manufacturing process.
I think in terms of applying S88 to a continuous process more in terms of the state that the process is in. Let’s face it, a continuous process has states. It has states during startup, and it has a fixed state where you’d like to have it run and never vary. What S88 does is provide the procedural control to get from state to state to state, until you’ve reached the proper state to run in. It’s a way to provide a control process from one stable state to another, desired stable state. It’s more than just starting up or shutting down. A lot of continuous processes will change products or grades on the fly. That’s a place where S88 can help a lot by institutionalizing the best practices and procedures for going from one state to the next.
Wilkins: I can upset the refinery guys by saying that the refinery process is one large batch. Batch was always seen as what you got relegated to when you weren’t good at doing the other stuff. It’s interesting that I’ve been schooled in both sides, and I find batch much more interesting. So to tell a refinery guy that it’s a big batch is a good way of upsetting him.
Question: Is that why S88 usage is lower in the petrochemical industry?
Wilkins: Yes. Batch has always been seen as somewhat inferior to their wonderful optimizers and things like that. Don’t get me wrong; those are wonderful control tools, but there’s a lot that batch can offer. There are so many applications and operations in a refinery or a continuous petrochemical plant that the batch standards could help with, but they just don’t use it. Oil movements are a good example. Startup and shut down of any one of a major unit, and recognizing and reacting to any abnormal situation…there is no common way that they handle those, and abnormal situation handling is becoming a big deal now. That’s something we have taken for granted in batch since the year dot. So I think there’s a lot of scope for the future there.
Craig: I think batch has an image problem, mainly because 10 years ago or a little more, 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. People did batch, and it just didn’t fit into the high tech world. We fixed that with S88, but a lot of people don’t know it yet. S95 is there to deal with management of the entire manufacturing process. Manufacturing operations management is what it’s really all about. There are many different kinds of processes, many of which S88 can deal with. I see structured procedural control of continuous and discrete processes emerging as separate views of the same standard.
I can tell you what I think ought to happen next. S88 was written at a time when the problem to be solved was batch control. It is written in unabashedly batch terminology. A lot of that gets in the way of people understanding how to apply it to other kinds of processes. It seems to me that we’re going to have to have guidelines, or perhaps even separate standards addressing the various kinds of manufacturing using S88’s principles. I think that’s needed because the terminology and the language turns people off. They have to interpret, and a lot of people don’t like interpreting.
Wilkins: I agree that there’s more work to be done with S88. Coming back to S88 and S95, there are some needs in some industries to combine the two together into some kind of modular automation standard. There are some industries that will get scared off by the word “batch.” It was more than 10 years ago now that S88 was brought out, and it does need refreshing. There’s a need to bring all of the parts together, and I do know that the SP88 committee is starting to talk again about a revision, and that’s coming along too.
Craig: There’s an active working group looking at revising S88.01, and there’s also an active working group trying to define how S88 and S95 work together. I think S88 and S95 will work well together, once we get all the bugs out and all the lines of communication clear. One of the things holding back process automation technology is that we didn’t have good communication with the business aspects of the company. One reason MESs haven’t been as productive as they should be is that, in the past, they haven’t had good connections to the manufacturing process. So I think the linkage of S88 and S95 helps both the quality of automation and the quality of the management of that process.
Wilkins: The state of the batch is good. It is going in the right direction. The standards are in place, and all of the suppliers have control systems that address the issues around batch. There’s a lot of activity still around the standards, which is a good thing. As I said earlier, they just need to get adopted in a broader sense and in a wider sense. They need to reach more of the people they were intended reach in first place. In an adoption sense, they’re getting out there, but the people who need to understand them are still not getting it.
Craig: There’s still a lot to learn. A lot of people have to learn a lot. I think we need to get two or three things going at the same time. WBF has been trying to address these things, and has been for its entire existence, but formal education on the theory and implementation of batch control is still needed. We need to learn how to use this stuff, from the real nuts and bolts things all the way back to the theory. Continuous processes have developed a good deal of theory on optimizers and so forth, probably spawning more Ph.D theses than any other topic. We could use some of that in the batch and process automation worlds.