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Tuesday, June 10, 2008

St. Clair Water Treatment Facility

HMI/SCADA Powered by InduSoft Ensures Clean Water and Goverment Compliance

 

  • Replacing the old-style hard panel with a PLC/LCD HMI screen was a snap and the result was a more intuitive, easier to use system.

  • The system employs three independent, redundant, stations that use a simple master-slave failover system

  • InduSoft Web Studio was so easy to use, Majority Controls began development after only one day of training.
InduSoft Web Studio enabled Majority Controls to create a redundant HMI/SCADA system that ensures a safe and abundant water supply from Lake Huron


Introduction

Clean water. It’s not a luxury; it’s a life-giving necessity. Consumers demand it—and so do both the Federal and State governments across the United States. In Michigan and surrounding states, the Great Lakes provide the water, but the unique nature of the watershed poses challenges that require stringent regulation.

As the largest bodies of fresh water on the planet, each of the Great Lakes is the primary water source for millions of people. Each lake, however, is also part of a complex system that flows from Lake Superior to Lake Ontario and from there to the Gulf of St. Lawrence. As the water flows from one lake to another it is used not only for drinking, but industrial and waste disposal as well.

It begins as crystal-clear, pure water that’s suitable for drinking right from the lake, but—without intervention—down-stream lakes would begin to accumulate toxic amounts of chemicals and waste. In an effort to ensure the purity of the water, government regulations—in particular the State of Michigan—have very demanding requirements. The water must be constantly monitored for turbidity and pollutants.

Furthermore, recent Michigan legislation also now requires water treatment plants to keep monitoring records for seven years.

For the water treatment plant in St. Clair, the new regulations meant that it was in dire need of an upgrade. Michigan Controls was the vendor of choice for the project and they recommended modernizing the outdated HMI/SCADA system to ensure compliance with current state and federal requirements. To that end, Michigan Controls partnered with Majority Controls, headquartered in Port Huron, Michigan, citing their vast experience in HMI/SCADA systems. Majority Controls chose InduSoft.

The sleek new LCD HMI screens are light-years ahead of the old outdated hard panels they replaced.

The sleek new LCD HMI screens are light-years ahead of the old outdated hard panels they replaced.

The Challenge

Because of the stringent monitoring requirements and the necessity to keep continual records for seven years, it was necessary to have a system that provided highly redundant capability, ensuring optimal operational uptime. Michigan Controls wanted to be able to run the system from three different operator stations. In the event that any two of the systems failed, they wanted to ensure that the third system would enable operators to continue to monitor and record data.  Any lapses in monitoring or historical records would result in fines and penalties—not to mention the public safety risk. Michigan Controls wanted to avoid such a contingency at all costs, so high redundancy was absolutely critical to the system.

Ease of use was also a sensitive issue to the customer. They were using a system that was written in raw Visual Basic, which made changes to the system labor intensive. They needed a system that would be easy to use, easy to learn, and easy to implement. According to John McKenzie, co-owner of Majority Controls:

“The previous system was developed using older technology such as Visual Basic. We really wanted to move away from that kind of language-based solution and toward an environment in which ease of use was paramount. We saw the InduSoft Web Studio configuration interface and it was exactly what we envisioned.”

McKenzie continued “The drag-and-drop paradigm simplified the development process to a clean exercise centered on configuring the overall system to meet the regulatory requirements, rather than writing reams of Visual Basic code.”

“Our focus was assisting the municipality to meet federal and state guidelines and to ensure that they had a highly redundant, reliable system. After all, we’re not in the business of being experts on a specific HMI/SCADA development or configuration system. InduSoft Web Studio was very easy to use, which minimized our ramp-up time. It enabled us to focus on the customer’s need for a functional, user-friendly system.”

And as a Web-ready toolkit, with built-in database support, InduSoft made the HMI/SCADA implementation that much easier.

Everything from turbidity and purity levels to the actual tank levels is recorded every 15 seconds enabling reports and trends.
Everything from turbidity and purity levels to the actual tank levels is recorded every 15 seconds enabling reports and trends.


The Solution

Majority Controls first replaced the hard panel with a modern PLC and LCD panel arrangement, which functions as a backup to the three operator stations. At any time, one operator station is designated as the system master, and the other two are designated as system slaves.

The designated master handles all PLC communication over an Ethernet connection and also transmits tag information to the slave systems by TCP/IP Client/Server communications. The Server records data to a network database once every 15 seconds.

Each operator station is assigned a priority from 1 to 3, 1 being the highest priority. A simple handshake among the three operator stations enables each station to monitor the health of the other two—each sending out a heartbeat that the other stations monitor.

Initially, the station with the highest priority is designated as the system master. As long as the slave stations detect the heartbeat from the master, they receive their data from it. If, however, the master station stops sending its heartbeat because of a failure, the station with the next highest priority takes over. The function of communicating with the PLC and transmitting data to the remaining slave is then assigned to the higher priority slave, which becomes the functional master.

In the unlikely event that the new master station goes offline, master control is assigned to the remaining slave. As stations come back online, the system with the highest priority will resume operation as the master and the others will return to slave operation. John McKenzie elaborated:

“The ability to easily build redundant capability using the built-in TCP/IP Client/Server system was a key factor in our decision to use InduSoft. Creating that capability in the other systems we evaluated was far more complicated.”

As control is passed from one machine to another, the designated master continues to log data to the primary network database—but that’s not all that can go wrong in such a system. Databases can also become inaccessible.

If the primary database becomes inaccessible, the master station will log data to a secondary database, which is often—but not always—local to the designated Master station. When the primary database comes back online, the data recorded in the secondary database is automatically forwarded to the primary database. “This feature alone saved us several days—if not weeks—during the implementation.” said McKenzie. “The redundancy capability and the ability to enable automatic failover and database synchronization are built into the InduSoft configuration system, so we didn’t have to program that feature. A simple database configuration wizard walked us through the database setup in no time.”

State requirements mandate that certain water purity conditions must be checked regularly and their levels recorded. In the event of a purity level fault, written reports must be created, indicating when the fault occurred, the actual levels leading up to the fault, as well as the status and running time of the various pumps and filters prior to the fault. Using InduSoft’s built-in reporting functions made it easy for Majority Controls to generate the necessary database queries and summary reports to meet the customer’s requirements.

The Result

At the end of the day Majority Controls was able to exceed the customer’s expectations. The resulting system not only operates within the new regulatory requirements but also enables better customer service. The failover redundancy helps to ensure that failures are rare and that the appropriate person is immediately notified if a failure does occur. The continual data recording capability also gives management the required tools to run the plant more efficiently.

The customer is so pleased with the system they’re considering an extension to it that would enable remote monitoring and management. Using InduSoft’s built-in e-mail and Web-ready capability, operators will be able to receive alarms and notices by cell phone and e-mail. Logging into the system remotely through a VPN tunnel will also be available.

Majority Controls began the process with minimal training and required very little support throughout the implementation. According to McKenzie “We started this project with just one day of training from our local InduSoft sales representative, and we required only about five short phone calls to tech support in Austin, Texas to handle specific questions. By the time it was over I think we used just about every feature of the product. It was one of those projects that could have been a major headache, but when all was said and done, we were amazed how well the whole system worked and how smoothly the effort unfolded.”

The main Fault screen enables operators to monitor literally dozens of potential faults as required by law, while simultaneously recording every alarm as it occurs in real-time.

The main Fault screen enables operators to monitor literally dozens of potential faults as required by law, while simultaneously recording every alarm as it occurs in real-time.


 


For more information contact your local distributor or InduSoft directly at

info@indusoft.com or 877-INDUSOFT (877-463-8763) or 512-349-0334.


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