Water and wastewater operators rely on SCADA systems to monitor and track nearly every aspect of their operations – from process treatment to water distribution and collection. In fact, over the last 40-plus years, SCADA systems have grown in functionality from simple on-off operations to highly sophisticated tools that manage large water and wastewater operations. 

In a nutshell, a SCADA system gathers information about an operation, transfers it back to a central site and displays it in a logical and organized fashion. SCADA systems can be relatively simple – such as a single personal computer coupled to a lab or small water treatment facility to monitor environmental and other conditions – or incredibly complex, such as those systems that monitor and control all the activity in a nuclear power plant, refinery or large municipal water system. 

“The SCADA system is critical to water treatment because it provides the operators a window into the operation of the system,” explains Dave Lee, director of TIW Solutions at Siemens Water Technologies, a provider of SCADA systems for water, wastewater and industrial applications. “More important, the SCADA system serves as an emergency warning system if something fails, which in the case of water can dramatically affect public health.” 

Troubleshooting tips proposed 

So how do you keep those SCADA systems in top operating condition? Lee proposes four common-sense ideas for troubleshooting: 

• The core of all SCADA systems is communications. Network communications and telemetry communications are links that transfer data from distributed control and monitoring modes both in-plant and out-plant. A well-designed SCADA application will monitor all system communications, represent the status of all vital communications links graphically and provide alarm notification to the operator if any of the links fail. 
• An effective SCADA system should include the proper complement of spare components that the operator can swap out easily for troubleshooting purposes. These spare parts should include Ethernet routers, PLC processors, radio modems and other components that are preconfigured for use in the system. 
• Once a SCADA system has been started up, debugged and commissioned, most issues are not software related; they are typically hardware failures. Most problems are related to power supply failures, I/O (input/output) card failures, transient surges and other glitches. Check the basics first, starting at the output and working backwards towards the origin of a given signal, input or output. 
• Variable Frequency Drives (VFDs) are often specified for rotating equipment (pumps, blowers and chemical feed units) for their benefits in process control precision and energy savings. They are often a point of failure because of harsh operating conditions. That’s why it’s important to ensure VFDs are properly protected from overheating and dirty, dusty environments. 

Maintenance ideas 

Why is maintaining a SCADA system so important? Mike Schmidt, Siemens Water Technologies technical sales manager, answers, “SCADA systems are like any mechanical system – they require regular systematic maintenance to ensure optimal performance and longevity.” 

Schmidt offers maintenance suggestions as follows: 

• Timely software updates for the PC, PLCs, SCADA application software, communications routers, peripherals and so on.
• Power supply systems, including Uninterruptable Power Supplies (UPSs), batteries, etc., should be checked routinely to ensure they are operating within specification. Replace batteries as recommended by the manufacturer for all devices.
• Routinely check field connections for moisture infiltration and corrosion. This is especially critical in remote locations or places subject to salt air or corrosive sewage gases. 

Typically, SCADA systems are tailored to specific needs. They are custom applications, not off-the-shelf purchases, hence the smaller the facility, the lower the SCADA system cost. The water/wastewater industry looks at SCADA systems that combine monitoring and controlling the plant itself as well as assets in the field. Industries use systems that monitor and control what they make, whether it’s oil refineries or cereal or automobiles. 

“SCADA systems help lower energy costs, reduce maintenance costs, and optimize processes,” Lee says. “We’re pleased to provide and help maintain these systems which are vital to industry and water/wastewater operations.” 

For some suggested SCADA systems and components, check out www.tpomag.com/editorial/2013/04/monitoring_and_instrumentation4.