PROFINET – Not Pregnant Enough in San Diego

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Last week marked the kickoff of our 2014 one-day training classes with the San Diego class. Everything went pretty smoothly considering we have a new approach this year. We jump right into the “How do I” sections after a short introduction. Some of those sections include a behind the scenes look at how PROFINET does that. That information is not needed to use PROFINET, but I think it helps to understand how to apply it. Almost all the sections include a new example of how someone used PROFINET. Some of these are presented in detail on our website.  We also do live demos in many of the sections, although we have some video demos, too.

I really appreciate that almost every student takes the time to complete the course evaluation. We are machine scoring them this year so it’s easier to quantify how we’re doing. Quantification is good, but I really like the “verbatims.” “Verbatims” is survey-speak for open-ended responses. A theme in the responses was praise for the MinutePROFINET videos. We used some as summaries of particular sections. (You can view all of them on the MinutePROFINET YouTube channel. ) One student was especially appreciative of the Resources slides that we included in every section. Each item listed included a link to additional material on the topic – webinars, documentation, videos, and more.

My favorite verbatim was this one:

“Not deterministic enough” is like being “not pregnant enough.” Don’t use that phrase.

I will certainly agree that being pregnant is binary – you either are or are not. But I’ll defend my “not deterministic enough” phrase a little bit. I think determinism, like speed, depends on the application. So what might be fast enough for a process instrument is not fast enough for factory automation. Determinism follows along with that. I’m considering that determinism is defined as “a message arrives when I want it to.” There is a tolerance associated with determinism. The deviation from the target delivery time is “jitter.” Missing the target by tens of milliseconds may be ok for a process instrument, but it is not deterministic enough (there, I said it) for factory machines. In other words, the tolerance for jitter is tighter for machines than instruments. Feel free to disagree in the comments.

An aside: San Diego in February – Sometimes people wonder if we consider the weather when we schedule classes. You bet! Just look at the schedule. It does not always work; a couple years ago we got low attendance due to snow in Atlanta.

–Carl Henning

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