Signal Isolators

The City of Dubuque, Iowa's new Water Division computer system was experiencing failures of the analog inputs ranging from signals out of tolerance by more than 30 percent to intermittent and sometimes complete loss of signals. The problem stemmed from a lack of signal isolation of the analog input cards, which made the inputs vulnerable to interference from storms and machinery. Electronic technician Bob Ervolino read an article in Tech Briefs describing an Ames Research Center solution to a similar problem. He studied the Technical Support Package and contacted the vendor; the information saved the Water Division more than 50 percent of the cost of commercial isolators.