Do It Yourself SCADA Replacement

Pumps & Systems, September 2007

This municipal water system evaluated the cost of upgrading their existing SCADA software and decided it was time to consider replacements. After much research, it became clear that not only was it possible to get all the features they were missing; they could also do most of the configuration in-house. 

Named in honor of George Washington, Georgetown, KY is home to 20,000 residents, a private liberal arts college, and one of the largest car manufacturing plants in the U.S.

Water and wastewater services for the city are provided by the Georgetown Municipal Water & Sewer Service (GMWSS) which operates the water plant, three wastewater treatment plants, the few dozen lift stations and the five water towers. These assets are monitored and controlled by approximately 30 remote telemetry units (RTUs), each communicating with a central base station RTU over spread spectrum radio.

At the heart of the water plant are five Worthington pumps. Two of these are high service 3700-gpm units driven by 250-hp, 3-ph, 460-V U.S. Motor engines. The other three are low service 1780-gpm units using 25-hp, 3 phase, 460-V U.S. Motor engines.

The Frankfort booster station employs two ITT A-C Series 8100/Model 300 6000-gpm split case pumps with 150-hp, 3 phase, 460-V motors. The Lloyd booster station uses three Peerless pumps: one is a C825AM, 15-hp, 300-gpm unit; the other two are C1140AM, 100-hp, 850-gpm units.

 

Wastewater treatment plant #1 consists of four different pump stations. The Pleasant Valley station contains a Gorman-Rupp T8A3S-B/WWS pump with 800-gpm at 67-ft TDH. The Etterwood station uses a Gorman-Rupp T6A3S-B/WW pump with 600-gpm at 77-ft TDH. The College station has a Myers 4VLX1250M4-43-30 1200-gpm submersible pump with a 125-hp motor, and the Colony station uses a Myers 4VCX20MR-43-25 submersible pump with 565-gpm at 85-ft TDH.

Wastewater treatment plant #2 contains Flygt 3202.090 submersible centrifugal explosion-proof pumps with 60-hp, 460-V motors, designed to pump 900-gpm at 112.25-ft TDH.

The Legacy Software

When Shawn Derrington came aboard two and a half years ago as the IT director of GMWSS, he inherited a SCADA HMI software application that posed a variety of challenges for users: "There was nobody to maintain [the original software]. There were lots of things we couldn't do with it or didn't like about it, but we had no way to make changes." 

Challenges included:

1. Information could only be monitored via two unconnected HMI computers: "The water plant operators had the main computer at the plant for reference and system control," says Derrington. "Anyone else wanting any system information had to go there, or call and ask. The second computer was at our Wastewater Plant #1. It monitored all of the pump stations for runtimes, power fails, seal fails, etc. and was only available in one building on the far side of the complex."
2. Limited report manager: "All we had in terms of historical data were these daily and monthly reports of runtimes and flows," explains Derrington. "The reports were stored as individual text files, so there was no easy way to compare or compile data."
3. Third party alarm dialer: The system used a third-party alarm dialer that posed serious compatibility issues during software upgrades or version replacements.

GMWSS also wanted to eventually tie in several RTUs that were being monitored by a separate cellular-based SCADA system, but there was no practical way to implement this with their existing SCADA central. Once they decided their existing SCADA HMI was simply not meeting the utility's needs, GMWSS began looking at a system upgrade where priorities included:

1. Sharing real-time and historical data across the network with engineers, managers, and a variety of other users.
2. Comprehensive reporting, trending, and handling of historical data.
3. An integrated "all-in-one" solution without version compatibility issues and expensive add-ons for mission critical features.
4. The ability to make changes to the system in-house as the needs of the utility evolve.
5. The ability to communicate with existing monitoring devices as well as devices from a variety of other manufacturers.

A Fresh Start

Derrington realized that expanding his existing system to include new features would not only be expensive, but GMWSS would also continue paying yearly support fees for these new features indefinitely. 

There was also the issue of making changes as the infrastructure continued to grow. "We ultimately wanted to make our own edits and change things around," remarks Derrington. "We started thinking that a whole new system was the way to go."

GMWSS worked with local system integrator Rawdon Myers to develop their PLC SCADA program, which laid out the groundwork for the HMI requirements. With this information, they began the process of identifying possible SCADA software replacements. 

After significant research, they compiled a shortlist of new SCADA contenders. Some of these were eventually eliminated because they also required third-party components, such as alarm dialers, and therefore presented the same compatibility issues as the current system. GMWSS eventually selected VTScada after receiving positive comments from Rawdon Myer and visiting other existing installations in the area. 

HMI database Conversion

Derrington originally assumed the HMI database for the existing SCADA central would have to be rebuilt from scratch, a job normally requiring a significant amount of time and money. "We originally planned to hire a system integrator to build the new system while giving me basic training so I could maintain the system going forward," he adds. 

Instead, GMWSS adopted SCADA software that included an integrated database conversion utility. Database conversion is an approach used by many utilities and system integrators alike for saving time and reducing the likelihood of costly errors. "Being able to convert our old database was huge for us," says Derrington. "That saved an untold amount of time and prevented data entry mistakes. After doing some of the web tutorials, I soon realized I could do most - if not all - of the development myself."

Phase I: Planning

Derrington suggests that anyone considering this kind of project should take the time to plan as much as possible in the beginning: "We had a pretty comprehensive idea of where we were going with this because we took our time and spent several months looking at different products and testing."

 

Taking a detailed look at the facilities to determine what is actually necessary is important. "A couple of our lift stations are very small and were simply deemed unnecessary expenditures for monitoring," notes Derrington. "We spent a significant amount of time just documenting the system tags, radio settings, PLC logic, etc. for our entire system." Having this information in one place can pay off for years to come - especially when working with outside contractors or system integrators.

"Settle on one idea for your page layout so you won't have 30 pages that look different. Set up a standard so operators expect information in the same places," states Derrington. "Previously, the controls and pump information our operators needed to see were spread across three different pages." 

GMWSS used aerial photographs of Georgetown's treatment plants and pump stations to create visual navigation that would be instantly familiar to operators and staff. Another simple and effective way to instantly convey important context for information is to use standard sets of colors for groups of pages or tags. 

NOTE: While it is important that applications look good to users, excessive use of graphics can actually distract from the information being displayed and drain system resources. "The important thing is to allow [operators] to get on with what they are doing," Derrington points out. "It's just a tool for them." 

Phase II: Development

The first treatment plant took GMWSS a couple of months. They bought the software that April but didn't go completely live with it until the middle of October, largely due to the documentation that needed to take place. "We had probably three months of running both systems side-by-side for testing and ensuring the data was the same," explains Derrington.

By the time he began developing the new system, Derrington had already created several working SCADA applications based on step-by-step tutorials. This experience honed skills that helped him work more quickly and efficiently. For example, the key to copying and pasting system pages and tags was to make new pages and tags as generic as possible. "Though there are 25 pump stations, probably 80 percent of each pump station is identical, so I can just copy a page and change the tags," he says.

Do not underestimate the time commitment involved in doing this work in-house. Although Derrington didn't have to abandon all his normal day-to-day duties, "It took a large part of my time." Many utilities cannot dedicate these kinds of resources and are more comfortable hiring a system integrator.

Support

Though he configured the application himself, Derrington stresses the importance of choosing a manufacturer that can provide the technical support needed to support that process: "We like that [our SCADA contact is] a smaller company; you can actually talk to people you know. They are always easy to get a hold of or will get back to you quickly. You never have a concern that a voicemail or email you've left is going into oblivion."

 

The Final Result

Through research, planning, and a little help from their friends, GMWSS now has a SCADA system that meets all their requirements and can grow with them. "We are thrilled with what we are able to do in-house. The data we can now share among the departments is vastly superior to our prior system," says Derrington.

The integrated Internet server and alarm dialer allow mission critical information to be securely shared, both inside and outside the organization. "With virtually no training, users simply select the object or process that interests them to find out what it's doing - without calling me!" notes Derrington. "If I'm off duty and supervisors get a call, they can VPN into our network and see the status of certain things without having to physically drive in."

Derrington stresses the importance of their new integrated trending utility: "Our operators can click on any tag and get a real-time trend. Another click and they can change the time scale. They can add other tags to that same trend by simply clicking its tag. This is incredibly valuable to us because we don't have to anticipate every trending need they may have and create a separate page for it. We also don't need to go through a report generation process to see trend information."

Thanks to an extensive library of device drivers, the open SCADA system can incorporate a wide variety of new hardware. In the next few months, GMWSS will bring five new lift stations and a third wastewater plant into their new system. They are currently monitored by a cellular-based SCADA system. GMWSS will use their OPC Server application to port that data directly into [the new SCADA system] to make all telemetry data available in one place.

With GMWSS now able to make changes to its own SCADA system, Derrington is enthusiastic about the future.  "We couldn't be any happier with how it's turned out so far."