SEVERAL THOUSAND MAN-YEARS OF EFFORT HAVE GONE INTO FIELDBUS TECHNOLOGIES OVER THE PAST DECADE OR TWO. Though simplifying installation is a central aspect of this ongoing design effort, installing a network remains a difficult task. Meticulous planning can eliminate many problems, but that doesn't mean everything will fall into place when the switch is finally turned on. For more than five years before the Dekalb County Department of Watershed Management opened a water treatment plant in Decatur, Ga., engineers made preparations that included network design. The network is expansive: a dual-redundant fiber optic network that runs two miles, connecting more than 300 Profibus instruments and 300 DeviceNet points. But all that planning and close communication with the system integrator who installed the network didn't matter when an intermittent failure struck one half of the network.
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