A Vice President of Software at Rockwell Automation casually dropped the thought of PLC as an edge compute device during our conversation. Since I spend considerable time talking with people, especially in the IT realm, about the edge, this piqued my interest.

Can a PLC be an edge compute device?

Just prior to my going away on vacation, several Rockwell people met with me to discuss this idea of PLC as the edge. The idea was repeated at least twice, so it’s important. “Our strategy is to use the PLC as a concentrator. We will use technology from the ASEM acquisition to develop a compute platform for the PLC.”

Here is my context leading to seriously asking the question. Before there was Edge, Cloud, Internet of Things, and the rest, several people talked with me about a problem of a large automotive plant. The IT manager required data from a machine to feed his enterprise system. If he went to the control engineer to ask for the data from the PLC, he met considerable resistance. The engineer would be required to get into the control logic and set a few lines of code to send that data. As we all know, any change to a control program can lead to unanticipated downstream situations that are detrimental to operations.

The solution included wiring a sensor around the control system to a small compute device which then communicated to the IT system. IT got its data. Bothering the control engineer was avoided. Win-win as they say.

We did not get that far into the system before we had to end the conversation. But that is the question I still have—can Rockwell engineer the system so that IT can get data without disturbing the control system? That means the PLC-rack-mounted PC can be read the data table but completely outside the control system. Security would also necessitate some similar arrangement.

Using the PLC as the central point of compute for Rockwell Automation makes sense from a corporate strategy point of view. The company has always kept things close. It is seldom open. They would, of course, point to DeviceNet or “EtherNet/IP” as open or its occasional use of OPC, something that has picked up recently. Rockwell has acquired PC talent over the years, so the recent ASEM acquisition probably means that there wasn’t that much further development of the PC product lines, so they went out and obtained more talent.

One of the team was from the analytics group. Yes, Rockwell has had an analytics product for years. This is seen as an integral part of the edge strategy. It sounds like the strategy includes bringing control, compute, and analytics together at the edge. Perhaps this will evolve into service offerings? There was a mention of providing compute as a service (not sure if they meant CaaS).

Sounds like time for an updated training session for the old guy. They discussed the PLC moving from tag-based to object-based. We had no time to go further into that, but it certainly sounds intriguing.

I mentioned that mostly edge to cloud referred to Internet of Things. IoT generally refers to IT rather than control. The Rockwell response it that it is better to take IoT through PLC. Once again, this sounds like a long-held Rockwell strategy of keeping everything as close to the vest as possible. Most people refer to IoT as more open than part of a closed system.

Toward the end of our conversation, enhanced services were mentioned. Time ran out, however. That would not be surprising. Ever since the dawn of M2M, the precursor to IoT, the principal business objective included selling services. That’s the trend everywhere.

If I were a “real” analyst, I’d have a model with a Three-Letter Acronym and conclude that this strategy fits that model. Or perhaps five quadrants and place it somewhere.

Just being a thinker, I’d say that what was discussed in this briefing fits squarely within Rockwell Automation’s established strategy extending that with enough of the latest technology and just enough openness to keep its major customers happy. Whereas much of the world is becoming more open (standards, open-source, and the like), Rockwell has always been as little open as possible. And, by the way, that is not unique. Only one competitor evangelizes open standards, and I’m not sure about it.

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