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Industrial Ethernet Book 103

Cloud-based, cellular SCADA system for water treatment Systems integrator Perceptive Controls has designed a cloud-based, cellular SCADA system for rural water and wastewater treatment systems. By using a RESTful API, developers gained secure, programmatic access to data from new or legacy physical assets wired to a programmable automation controller. LIKE PLANTS AND PEOPLE, cities need water to grow. The average American’s daily use of water reaches upwards of 100 gallons. Major cities like New York, Chicago, and Los Angeles need billions of gallons of water per day. And when people turn on their faucets, they expect the system that delivers their water to just plain work. In reality, a lot more goes into delivering clean, potable water than most people realize. Transporting water and wastewater throughout municipalities is a complex task that requires significant investments in advanced SCADA technology. But not all water districts have the budget to acquire the necessary technology. The challenge Modern water and wastewater treatment regulations require water districts to maintain systems for monitoring, data acquisition, alarming, and reporting on the quality of water delivered to residents. While large cities can afford the technology investments required to transport billions of gallons of water per day, smaller water districts, often located in remote and rural areas, can struggle to find the budget required to implement a modern SCADA system. Instead, processes remain manually driven and as a result are prone to errors that can lead to a system failure. The rugged and remote location of many rural water districts can also pose a challenge in implementing a SCADA system. Most modern municipal water systems use some form of wireless technology, often 900 MHz radios, to establish a SCADA network between remote sites. These radios are a good solution for SCADA networks because they operate in an unlicensed spectrum and do not require a service provider network to relay data from site to site. However, in rugged terrain it can be difficult to obtain the direct line-of-sight connection 900 MHz radios require. Cellular connections are often the next best option to establish a SCADA network between remote sites. But the data charges associated with cellular connectivity can be cost-prohibitive, due to the scan-based poll/ response communication architecture of traditional SCADA systems. Recognizing the needs of smaller water and wastewater treatment plant operators to add affordable SCADA systems to their operations, systems integrator Perceptive Controls developed a cellular, cloud-based SCADA system called Perceptive Polaris to overcome these challenges. The solution Using Perceptive Polaris software with an Opto 22 SNAP PAC control system, Perceptive Controls was able to deliver a low-cost SCADA system that avoids expensive servers and hardware while still delivering the monitoring, control, alarming, and reporting capabilities water and wastewater plant operators require. One of the key challenges engineers at Perceptive Controls faced during development of the solution was how to reduce the amount of data sent between lift station sites on the SCADA network. “We knew that using cellular modems meant one of the most important requirements of this project would be the ability to transmit the smallest data packets possible, with as much data in each packet as possible,” said Kevin Finkler, software engineer for Perceptive Controls. “We had to stay under the data caps of the cellular provider we planned to use.” “Our original design was to use a script running on an Opto 22 PAC-R2 controller,” added Finkler. “The script would collect data from municipal equipment and perform an HTTP POST to transmit the data to a cloudbased server we host for our clients. The server is where our Perceptive Polaris software application resides.” During evaluation and testing of the first 22 industrial ethernet book 11.2017 SOURCE: OPTO 22 Using its Polaris software and a SNAP programmable automation controller-based system, Perceptive Controls was able to deliver a low-cost SCADA system that avoids expensive servers and hardware while still providing the monitoring, control, alarming, and reporting functions that water and wastewater plant operators require. Applications


Industrial Ethernet Book 103
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