The following tip is from the ISA book by Greg McMillan and Hunter Vegas titled 101 Tips for a Successful Automation Career, inspired by the ISA Mentor Program. This is Tip #22, and was written by Hunter.
I was working on a large automation retrofit project of a chemical plant that had numerous thermocouples scattered throughout the structures. A vendor suggested a particular thermocouple card that I had never used, and I was about to proceed with that card when I decided to quickly scan the specs on the card. There was an odd footnote about channel-to-channel isolation that caught my eye, and as I dug deeper into the details,
I realized that channels 1 through 4 and channels 5 through 8 shared a common ground on the card. Now, this plant was older and had a mix of grounded and ungrounded thermocouples. If I happened to get thermocouples from two different columns on the same group of channels, the resulting ground loops would have sent the readings all over the place. Luckily, I noticed this and was able to pursue a different path early in the design process. Details matter—take the time to chase them.
Concept: If you are not a detail person, either pursue a different career or LEARN to be a detail person. The field of automation demands extreme attention to detail. Wire size, materials of construction, flange size, flange rating, min/max flows, temperature, pressure, etc.—the list goes on and on. Failure to evaluate even one item can have serious or even catastrophic consequences. Check and recheck everything— “good enough” can shut down a plant or even get people killed.
Details: Engineering is by definition a detail-oriented profession, but the field of automation requires almost fanatical attention to detail. Everything matters, which is why instrument spec sheets have so many lines on them. Engineers who just copy/paste spec sheets from a similar transmitter or use a control panel design without understanding it will not last long in this field. Automation is particularly challenging because the engineering skill set is so diverse. In the normal course of a job, automation engineers might find themselves doing mechanical design, electrical design, and chemical process design, and each of those has a long list of details to consider. Obviously, a comprehensive list of the necessary details in the field of automation would take multiple books to cover and cannot be provided here. However, here is a list of examples that will help you learn to chase the details:
Watch-Outs: Always cross check vendor sizing calculations for instrumentation. Vendors often plug information into sizing software and generate impressive specifications and calculations, but they do not know the process, and they make errors. It is always worth running a rough cross check on their sizing and then reading through the entire specification to make sure the materials of construction are as required for the application.
Exceptions: None.
Insight: Many large engineering firms send a spec sheet with a smattering of process information to the vendors and let them generate the instrument specifications. This practice invites disaster. The vendor cannot possibly know the process details or the abnormal conditions that the instrument might encounter.
Rule of Thumb: Successful automation engineers HAVE to be detail-oriented. If this is not a natural tendency, then learn to color, cross check, or do whatever is required to be detail oriented.
About the Author
Gregory K. McMillan, CAP, is a retired Senior Fellow from Solutia/Monsanto where he worked in engineering technology on process control improvement. Greg was also an affiliate professor for Washington University in Saint Louis. Greg is an ISA Fellow and received the ISA Kermit Fischer Environmental Award for pH control in 1991, the Control magazine Engineer of the Year award for the process industry in 1994, was inducted into the Control magazine Process Automation Hall of Fame in 2001, was honored by InTech magazine in 2003 as one of the most influential innovators in automation, and received the ISA Life Achievement Award in 2010. Greg is the author of numerous books on process control, including Advances in Reactor Measurement and Control and Essentials of Modern Measurements and Final Elements in the Process Industry. Greg has been the monthly "Control Talk" columnist for Control magazine since 2002. Presently, Greg is a part time modeling and control consultant in Technology for Process Simulation for Emerson Automation Solutions specializing in the use of the virtual plant for exploring new opportunities. He spends most of his time writing, teaching and leading the ISA Mentor Program he founded in 2011.
About the Author
Hunter Vegas, P.E., has worked as an instrument engineer, production engineer, instrumentation group leader, principal automation engineer, and unit production manager. In 2001, he entered the systems integration industry and is currently working for Wunderlich-Malec as an engineering project manager in Kernersville, N.C. Hunter has executed thousands of instrumentation and control projects over his career, with budgets ranging from a few thousand to millions of dollars. He is proficient in field instrumentation sizing and selection, safety interlock design, electrical design, advanced control strategy, and numerous control system hardware and software platforms. Hunter earned a B.S.E.E. degree from Tulane University and an M.B.A. from Wake Forest University.