When Control magazine launched in 1988, process instrumentation and control systems had little to contribute to their own maintenance and calibration, much less the condition of process or auxiliary equipment. Back then, savvy plants performed preventive maintenance, overhauling equipment and calibrating instrumentation on regular schedules during annual—or more frequent—shutdowns. Day-to-day problems were spotted, diagnosed and corrected by experienced operators, engineers and technicians on the fly.
By 1991, we were writing about separate systems dedicated to monitoring turbines, pumps and compressors, mainly by detecting unusual vibration levels. At the time, these expensive systems were justifiable for only the most critical and costly equipment.
In the recession of the early 1990s, engineering and maintenance staffs were reduced and, in many cases, ultimately replaced by outsourcing and automated systems, a trend that has accelerated ever since, as the knowledge to maintain increasingly complex control systems has become more specialized, rare and costly, while the prices of automation sensors and information technology continue to fall.