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For example, Windsor Utilities Commission recently replaced its aging supervisory control and data acquisition (SCADA) system and built in greater redundancy. It also combined these improvements with a second project to upgrade medium- and low-voltage electric switchgear on high- and low-lift pumps at its Detroit River intakes, reservoir booster station, pumping stations and main campus.WUC has provided safe and reliable water since 1935, and presently serves 72,000 businesses and homes in Windsor, Ontario, Canada. It also sells bulk water to the nearby towns of LaSalle and Tecumseh. Its two main plants produce a total of 349 megaliters (mls) per day, which is slightly less than 90 million U.S. gallons (Figure 1). To accomplish its primary mission of water treatment and distribution, WUC has implemented the latest treatment technologies and is recognized as an industry leader in ozonation and meeting Ontario's Drinking Water Quality Management Standards (DWQMS).
However, WUC's innovations encompass more than ozonation and quality management, and its water treatment plant is one of the most advanced in Canada, according to John Stuart, WUC's chief operating officer, his team and their partners at Rockwell Automation.
In early 2010, Stuart and his colleagues recognized that their process controls were reaching the end of their lifecycle and needed upgrading. Rather than waiting for a problem to occur, they sought a solution that would not only bolster the system's data tracking and tracing capabilities, but also reduce the risk that a single-source failure could halt their operations. This meant WUC needed a fully redundant SCADA system with intelligent motor control and networking to improve system diagnostics.
"We don't have a lot of water storage in our distribution system, so we depend on our high-lift pumps," explains Stuart. "If there's any impact on the system, we have just 10 to 15 minutes to go to backup power. So we needed to get away from that potential single point of failure by changing our system architecture, splitting our electrical feed, and adding redundant I/O cards and processors."
Presently, WUC's treatment and distribution system has 2600 discrete I/O points and 900 analog I/O points monitoring the pumps and other equipment's starts, stops, flows, voltages, currents, alarms and other data points. "If the plant had kept its original control system and lost an I/O card, such as the one running the dosing pumps, then the control system would fail to add chemicals to the water, which would have compromised the water quality," adds Stuart. "In a redundant system, two processors and associated I/O cards would have to stop working for such a failure to occur."
Besides improving its tracking, tracing and redundancy, WUC wanted a system that could address three key areas:
Because of their longstanding collaboration, WUC again enlisted Rockwell Automation to help keep its facility on the leading edge of the water utility sector. The supplier's Systems and Solutions Business (SSB) team provided project management services that were instrumental in ensuring the correct hardware, software and overall SCADA system suited WUC's needs.
The two organizations also teamed up with system integrator Onyx Engineering Ltd. and consultant Insyght Systems to upgrade WUC's SCADA system, and help it implement wireless tablets for plant-wide control. To address the outdated controllers, Onyx installed nine Allen-Bradley ControlLogix programmable automation controllers (PACs)—eight with redundant powers supplies and one non-redundant. The SSB team helped design the control panels and supervised their installation. The PACs are integrated to help the utility's operators access plant-wide production information with real-time visibility of water quality, as well as trending loads, levels, clarity and alarms—ultimately enabling better plant management.To improve WUC's data tracking, tracing and reporting capabilities, Onyx installed Rockwell's FactoryTalk VantagePoint software, which delivers unified access to virtually all plant