If you cut your leg, would you take aspirin for the pain instead of closing/bandaging the cut?
A production line slowed noticeably, one day. The responding maintenance technician quickly restored line speed by adjusting the speed control setting in the programmable logic controller (PLC). Applause, applause, take a bow and move on to the next problem.
But what did this technician really fix?
Not the underlying problem, because he didn’t even look. He didn’t consult the equipment history, didn’t take as found data, and didn’t know the motor was drawing excessive current.
The technician didn’t stop to wonder why the control logic doesn’t automatically adjust the line speed based on measured speed. The answer is that when speed drops you don’t want to mask problems by adjusting the controller. You find and fix the cause of the speed loss.
The controller was, in fact, set correctly — until the tech changed the setting. The tech’s “repair” resulted in four hours of downtime. Don’t correct anything until you have the data to see what’s not correct.
