My magazine pile is virtual because most of my magazine subscriptions are for the digital version. Regardless of the virtualness or reality, here are some recommended reads:
“Avoiding the Culture of Double Fieldbus” in Control Engineering is a PROFIBUS application story. A key benefit to the user is the ability to use one fieldbus for both process instruments and discrete IO. With PROFIBUS only one set of configuration and diagnostic tools is required. The original print article stirred up a little controversy with the comment: “Profibus is also the only fieldbus which can support both process instrumentation and discrete devices on the same cable, using Profibus-PA and DP technologies…” In my opinion the word “cable” should be “protocol.” The process instruments (PROFIBUS PA) and discrete IO (PROFIBUS DP) use the same protocol on different media types. Some contested the word “only” insisting that Foundation Fieldbus can also handle both. Maybe, but when I looked around at ISA I found no FF discrete IO. Or, as Yogi Berra used to say, “In theory, there is no difference between theory and practice. In practice there is.”
Another application story (or two) shows FF and PROFIBUS side-by-side: “New application: Fieldbus technology breaks into electric utility industry.” Interesting sidelight was that the user knew a fieldbus was critical but had to convince their engineering firm! Key quote from Cyrus Taft: “But, if your initial design of the plant is done with fieldbus in mind, the savings are tremendous.”
Did you miss the Industrial Ethernet Symposium last month? I blogged a little about it here. You can find more information form ARC (“Field Report: 3rd International Industrial Ethernet Symposium”) and Automation World (“Industrial Ethernet’s Many Flavors”).
“Make the Network(s) Fit the Application” in Control Engineering has no fieldbus or Industrial Ethernet “brand names,” but provides a good overview on using industrial networks. My favorite quote from the article: “There’s no substitute for good engineering judgment.” There’s no magic bullet. There’s no single answer. That’s why we’re engineers. Of course, PROFINET (although not mentioned by name) clearly unifies the networks as in the tobacco processing example in the article.