After many years in the guild of crummy control engineers, I thought I would submit a magazine article for publication as I approach retirement.
I selected your trade publication for publishing for two reasons: Bela Liptak, and Greg McMillian. I met Bela at Crawford and Russell in the 1970s and Greg at the First Provox Users Meeting somewhere in the 1980s.
Of course, their work has benefited my professional career, and Greg's sense of humor seems to parallel mine. Hence, respectively submitted for consideration are my rules of I&C Engineering or simply Roth's Rules (below).
John C. Roth, PE
Field's Law: "The best control system in the world will never compensate for poor mechanical design."
McConlogue's Theorem: "The longest line on a piping and instrument diagram will invariably become the shortest pipe in the actual system" Converse is also true.
Draper's Rule #1: "You don't have any real problems until your control system doesn't work in manual!"
Roth's Observation: "Smart transmitters are really designed for dumb engineers."
Fritz's Rule: "Always buy pressure gauges with ½ in. NPT connections. They hold up better when the millwrights use them as step ladders."
Buehler's Bummer: "If a larger Cv means a larger hole, and there is no material in the hole; why do large Cv valves cost more? Shouldn't the absence of material mean they're cheaper?"
John's Advancement of Auto-Tune #1: "Self-tuning loops generate the highest gain values when used on noisy, batch or intermittent processes. Turn off the auto tune response and start with a gain of 1 and a reset of 10 seconds. Search for Ziegler-Nichols and read."
John's Advancement of Auto-Tune #2: "Forget the pricey auto-tune feature that has 400 menu items to define the limits of the auto-tune process. Use Otto to tune your loops. He works for cheap: schnapps, beer and bratwurst."
Charles' Law of Inverse Schedule Prediction: "When you first survey a plant and the simplest things have been made so complicated that they can't work and the serious stuff has been totally ignored, you are in for the long haul."
Sedey's Observation: "The worst thing you can hear during the first hour of a DCS FAT is 'It worked last time we tested it.'"
P&ID Inverse Curve Fit: "The integrity of the drawing information is inversely proportional to the number of signees in the Title block."
Horace's Lament: "70% of control valves are too big, 20% are too small, and 10% are both."
Economic Law of Controls: "10% of the budget, 90% of the grief. Grief coefficient increases the later a controls specialist arrives on project."
