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By Rich Chaplin, Senior Project Manager, CSI
Oct. 7, 2003 -- In less than nine days, live, and with no downtime, the City of Phoenix Water Department recently installed a new control system at its five-million-gallon-a-day Cave Creek water reclamation plant.
The following story tells how the City of Phoenix Water Department was able to accomplish this feat, as well as drastically reduce development time for its new five-site automation system. It also tells how the city is saving millions of dollars and thousands of hours by using UCOS, a state-of-the-art distributed control system, at its water/wastewater facilities.
Phoenix is one of the fastest growing cities in America, and that has put enormous pressure on the city's water/wastewater requirements. With continued, increasing growth, the City of Phoenix Water Services Department needed to dramatically upgrade the automation efficiencies at all of its water treatment, waste treatment, and reclamation facilities.
City Management staff and the City Auditor's Department management chose to install a UCOS® system developed by Control Systems International (CSI) headquartered in Lenexa, Kansas. This decision followed a two-year, department-wide study that involved the preparation of new, state-of-the-art process control standards and an evaluation process that has been thoroughly reviewed by Phoenix Water Services.
In the final evaluation, the patented UCOS system was chosen over Rockwell Automation and Westinghouse Process Control as the best technology to meet the future control system needs of the City of Phoenix Water Services Department.
"It is noteworthy that in addition to CSI being the lowest priced and most responsive proposer, they also were the overwhelming choice of two separate evaluation committees," stated the Water Services Department's funding request to the Phoenix City Council.
UCOS is replacing existing systems that are "obsolete or systems of lesser technology" at four sites: the 23rd Avenue wastewater treatment plant, the 91st Avenue wastewater treatment plant, the Union Hills water treatment plant, and the Cave Creek reclamation plant. UCOS will also be installed at the North Gateway reclamation plant, which is currently under construction.
We started by creating a detailed design document, including functional specifications, implementation standards for control strategies, human-machine interface (HMI) graphics, and tag definitions. We then used patented features in UCOS to embed those specifications into a water/wastewater-specific library of object-oriented device templates. This device template design process ensures consistent implementation of the specifications throughout all the projects and any future water projects.
UCOS greatly reduces system development time because the UCOS device library of pre-configured, pre-tested templates allows easy replication of devices with just the click of a mouse. This enables me to design control strategies in a visual environment with logic and tag definitions graphically displayed. The functionality of the control scheme can then be applied to any similar facility. In essence, once one water treatment facility is designed with UCOS, the same pre-tested and pre-configured device templates and control strategy can be applied to subsequent facilities. This has saved the Phoenix Water Services Department hundreds of hours in development and implementation time.
UCOS operates on Windows 2000 and is an open system that configures to most off-the-shelf hardware. In fact, UCOS means User Configurable Open System. This also saved the City of Phoenix Water Department time and money because they didn't have to replace any of the existing hardware and I/O subsystems at four plants.
The Cave Creek reclamation plant was our first cut-over. We started there by creating a "maintenance of plant operations" document which detailed the functionality of each of the plant's four controllers. With that information, I could then determine the best sequence in which to replace the old controllers with UCOS field control units (FCUs).
At Cave Creek we replaced an obsolete and unsupported GE/Parsons-XLS DCS with UCOS but did not replace any of the OPTO-22 I/O. This saved thousands of dollars because none of the I/O had to be rewired, tested, or debugged.
No fieldwork was required at this site, and the cut-over was done live, so there was no downtime for the system conversion. This was important in that the Enhanced Surface Water Treatment regulations require the plants to remain "100% operational," and that plant continued to reclaim four to six million gallons of water each day during cut-over.
Since the GE/Parsons system was originally installed with redundant controllers, we simply unplugged one side of the I/O chain and plugged it into our UCOS FCU. This was done sequentially with each I/O chain until all four UCOS FCUs were in place and fully operational.
In all, 2,500 real-world I/O points and 1,000 Modbus protocol points are controlled by three operator workstations, employing 135 HMI screens. What took us eight and a half days to cut over would have taken at least three months, if not longer, for a standard PLC system, and cut-over would have been tedious and difficult, at best. It is also doubtful that a live cut-over could even be engineered in three months with a PLC system.
By not having to rewire any existing hardware, we removed part of the human error element from the equation, and since this UCOS project is pre-configured and pre-tested we were able to check our system interface in a matter of minutes.
While preparing for the Cave Creek cut-over, we also developed and implemented new procedures and standards that will make all future cut-overs run even more smoothly.
Next we will cut over the Union Hill Water Treatment site, which treats 160 million gallons of water each day. Currently, Union Hill operates on a Siemens/TI system that uses Wonderware HMI, Siemens/Texas Instruments PLCs, and I/O. Managing and enforcing standardization of this type of configuration is difficult, so the Phoenix Water Services Department is having us replace the entire system except for the field wiring and fiber network.
Phoenix Water Services wants to use Modicon I/O, so we will use the existing wiring but replace all of the Siemens I/O racks with new Modicon racks. Since UCOS interfaces with a wide variety of off-the-shelf I/O, we have configured the UCOS FCU to scan the new Modicon Quantum I/O. One UCOS FCU can control up to four different I/O brands at the same time.
Union Hill's control stations are not currently integrated into the other Phoenix Water Services DCS. As part of the automation project we will integrate those stations into the UCOS system and also integrate the entire Cave Creek site into the system.
Since Cave Creek and Union Hill share some resources and personnel, both sites will be managed as one.
UCOS will monitor and control two different kinds of I/O at the two different sites. Both facilities will have the same look and feel on the HMI screens, and personnel from either plant will be able to operate Cave Creek from Union Hill or vice-versa.
When all five plants are upgraded with UCOS, operators who have proper security will be able to monitor and control any other plant on the system from any plant on the system. When the project is completed, UCOS will monitor and control more than 22,500 real-world I/O points across all five sites.
In addition to the five sites mentioned, the Phoenix Water Services Department has included in the contract a 100-percent option clause, which will permit it to install UCOS at five additional water production sites in the future. And because UCOS can readily adapt to new technology without downtime, UCOS will help keep the City of Phoenix's water and wastewater facilities operating smoothly, efficiently, and cost-effectively long into the future.
About the Author:
Rich Chaplin is a senior project manager for Control Systems International, Inc., Lenexa, Kansas. Chaplin has more than 18 years of experience in designing and implementing control and supervisory control and data acquisition (SCADA) systems from pipelines to petrochemical distribution terminals. CSI promoted Chaplin from project manager to senior project manager in 1995 to supervise CSI's involvement with the new 155 billion dollar (HK) Hong Kong Airport.
The airport uses UCOS for three distinct systems: (1) The General Building Management System (GBMS), providing control and monitoring of equipment within the terminal building; (2) UCOS airfield SCADA, providing control and monitoring of the airfield and landside areas including the water/wastewater system and vehicle tunnels; and (3) the FUEL-FACS+ fueling system, providing control and monitoring of the tank farm and fuel distribution system.
The combined systems involve more than 30,000 real-world I/O points and 640 remote locations spread out over the 12 million square-meter airfield.
To learn more about Chaplin's work with Control Systems International at CSI's UCOS web site: http://www.ucos.com.
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