Industrial Ethernet and the arch nemesis of AOL
By: Perry Sink Marshall
Recently on a Friday night I was getting on a plane, talking to the person just ahead of me in the jet way. I could see from his attire that he was a priest. I asked what kind. “Episcopal.”
He asked me what I did.
“Machine tools?” he replied. (A well-informed priest, apparently.)
“Sort of,” I said. “Sometimes machine tools. But more often robotics, material handling, process control.”
Suddenly a voice behind me said, “What protocols do you use?”
I turned around and saw this young guy with glasses, long hair, black pants and a black leather jacket.
“Ethernet, DeviceNet, Profibus, ControlNet, Interbus. Stuff like that.”
”Yeah,“ he said, ”I’ve used some of those.“
”What do you do?“ I said.
”Great,“ I said. ”Why don’t you sit down with me? Could be an interesting conversation.“
So I sat down in the Southwest Airlines’ ”party seats“ (the ones that face backwards) with a 19-year-old computer geek and a 57-year-old Episcopal priest. (Sounds like the opening line to a corny joke, doesn’t it?) The priest opened up a book called ”Modern Asceticism,“ while the computer geek and I discussed our mutual techno-fetishes of modern materialism.
By the way, I looked up ”Asceticism.“ It said: ”Asceticism denotes a system of practices that aims at the development of virtue and strength of character through self-denial and mortification. Methods include exercises such as celibacy, fasting, upright posture, periods of silence, performance of unpleasant tasks, and withdrawal from human companionship.“ Now that I think of it, writing software sounds like a synthesis of materialism and ascetics – days and nights of solitude in front of a computer monitor, with no sleep, and a strict diet of Dominos Pizza and Cola. Turns out this child prodigy computer guy graduated from high school a year early and skipped college. He works at a company that, for reasons that will soon become obvious, I cannot name. And yes, he’s 19 – meaning that he’s still a teenager.
I asked him what he did.
”My most recent project was reverse-engineering AOL’s Instant Messenger Protocol.“
I politely replied that I thought AOL epitomized the mediocrity of the huddled masses.
”True enough,“ he said. ”But the guys that wrote Instant Messenger really did a nice job. Very well written. Excellent software programmers, definitely. Not to mention, they’ve got millions and millions of customers all on the same network, and the whole service pretty much works for everyone. Kind of remarkable, if you think about it.“
He went on. ”However, I must also say that the stuff they’ve been turning out lately isn’t as good. Either they had a burp in the software department and lost some good guys, or else their deadlines are a whole lot nastier these days.“
I was thinking to myself, ”Hmmm… 19 years old, started programming right after high school, graduated a year early and just cracked the Instant Messenger code. Seems like this guy might be pretty smart.“
He started asking me about my industrial networking. So I started explaining this concept of ”real-time“ control networking.
”For example, one of my customers just told me my Profibus card updates the RAM in his PC six times a millisecond. That’s pretty fast stuff. Another example is CAN-based networks. Sixty four nodes on a single wire, operating in precise, bit-wise synchronization across the network at 1 megabit per second.“
”Well, yes, now I’d say that’s definitely real time,“ he agreed. ”I never liked that real time stuff too much. Tricky as all get out.“
I started to describe the automation industry. I explained how there are dozens and dozens of proprietary protocols, a half-dozen contenders that are open and, of course, the emerging panacea of Ethernet on the factory floor, which promises to solve all of these problems once and for all. ”Are they using TCP/IP?“ He asked.
My answer was yes.
”For real time control?“ he queried.
”Yes,“ I repeated.
”Why would anyone want to do that?“
”Because everybody understands it, and it’s simple and cheap.“
”But for real-time control?“
”Yes… that’s what everyone seems to want.“
”But it’s not cheap! Heck, the protocol stack is bigger than the application itself!“ he said. ”You need tons of processor power. And it’s not deterministic.“
”It is if you run every node through a switch,“ I replied.
”Well, then it would be sort of deterministic,“ he corrected me. ”Now all of these factories, like, they’ve got three-phase, 440-volt power and stuff running all over the place, right?“
I knew where he was going with this. ”That’s right. Plus they’ve got 50 horsepower motors turning on and off, and variable frequency drives. Maybe robotic welders, too.“
”And I suppose everyone wants to send all these signals in this grisly electrical environment with unshielded twisted pair, right?“
”That’s right… and with RJ45 connectors, if possible.“
The next thing I heard from my new teenaged bit-jockey friend was gales of laughter as he contemplated twisted pair Ethernet attempting to do real-time control with 440-volt power lines and motors all over the place.
The Episcopal priest, distracted by the laughter, looked up from his book on ascetics for a moment.
I paused to explain why everyone sees so many advantages in Ethernet. I told him that our industry is pretty fragmented. There are 10 different ways to do just about anything, and every major vendor has their own protocols that they use to keep their customers using their stuff.
I explained that this protocol incompatibility problem is a major source of irritation, and that if you’re trying to, say, get data from a PLC to the IT department, it can sometimes be pretty tricky. If you do all this with Ethernet, all those problems should go away.
He said, ”But I bet everybody doesn’t realize that even with agreed-upon application layers, vendors are going to find ways to keep some of the data in a proprietary or undocumented format. They ain’t giving up their turf without a fight.“
Geez, I thought, are there actually businesses other than automation where big companies use bait-and-switch tactics to lure customers into proprietary solutions and get them in a headlock? Hmmm.
I then decided to ask the Episcopal priest if he belonged to a particular faction of the Episcopals, or if he was ”independent.“ I thought this would add insight to our proprietary protocol discussion.
”No, I try not to take sides,“ the holy man responded. ”I think there’s merit to all those different splinters. Complicated as all get out, though, and a bit political. Better to not take sides sometimes.“
The hacker continued: ”Proprietary protocols are no big deal to me. You just decode them, like I did with Instant Messenger. The problem is, then, that those big companies will sue your ass. Of course, if you’re just doing it to pick up data in your own factory, they really can’t win the lawsuit. But still, if you’re a little company, and they’re a big company, they just force you to give all your money to the lawyers and bleed you dry.“ ”So is that what AOL is doing to you, then?“ I asked.
”Yes,“ he replied. ”We just got a cease-and-desist letter from AOL yesterday. It’s shaping up to be a really fun deal.“
”But you know,“ he added, ”We don’t run out of venture capital until November, and as long as I’m getting paid to do this, I feel it’s for the betterment of society.“
Ah, yes, the Betterment Of Society. Which, of course, is exactly why I’m out there every day, populating the world with food, fun and fieldbus – boldly emancipating control engineers everywhere from the shackles of proprietary architecture slavery. And, of course, the really fun part is annoying bureaucratic people in big companies. Kind of like my friend Greg in Ohio, who gets perverse pleasure from converting Allen-Bradley customers to Profibus.
I don’t know what the future holds for my AOL Instant Messenger reverse engineer pal, but I have a feeling our paths will cross again. Maybe my nodes will talk to his nodes next time they’re online. Maybe they’ll even defy the robotic welders and the 440-volt power lines, and do it over Industrial Ethernet… in real time.