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SCADA Improvement For Wastewater Treatment Facility

Project Summary Highlights:

Hardware/Software implemented:

  • Inductive Automation – Ignition HMI
  • Rockwell – CompactLogix PAC
  • Custom Control Panels

Key Improvements:

  • Obsolescence avoidance
  • Migration planning
  • Network design
  • PLC programming
  • HMI design
  • Reporting
  • Alarm management

A large public sewer authority, comprised of a wastewater treatment facility and 28 remote pumping stations, was using a legacy SCADA system with little visibility and central control of their system.  Only the remote pumping stations and a few critical plant flow signals were connected to the SCADA system.  The authority was aware of the expected remaining service life of the system, knew of the capabilities of present-day SCADA systems, and the new regulations required for their industry.  These needs had to be balanced against their budget.    PDA was consulted to provide a long-term solution that could help them achieve a balance.  Considering the limited budget available to the sewer authority, PDA provided a systematic approach to the upgrade, planning the work in phases.

Before improvements could begin, the sewer authority requested that a parallel control system be implemented.  This would provide the plant with consistent operation and ease learning of the new system until the legacy controls were all replaced.  To assist in the design, a tour and client workshop were arranged by PDA with a similar, successful project at a participating regional client.  This arrangement removed any reservations within the authority regarding the new SCADA application.  Sample HMI screens were built allowing the plant operators to gain experience with the conversion.

Overall, Phase One of the project went very smoothly.  Challenges on the project included harmonizing legacy and modern controllers and networks while limiting rework in future phases.  The remote sites currently are communicating through leased copper lines.  Although cellular was considered for future phases, the authority now plans on installing fiber to each remote site.  This will change the communications to Ethernet and will be able to connect each site directly to the SCADA system.  phases will include upgrading these to a consistent, industry-standard hardware, at which time a fiber-based network from a local service provider will be introduced.  PDA planned to ease the Authority into the changes, giving them exactly what they wanted, but minimizing scarring on the project.  Project scarring is most common when upgrades are phased. This means you must complete engineering to a certain level to achieve system functionality during a phase. The next phase may require rework from the first phase to continue advancements. This work is known as project scarring. PDA engineered the project phases to minimize the scarring while designing each phase to fit within a municipal’s budget constraints. This allows municipals to enhance their systems while making each phase financially manageable.

The next phase will involve the addition of Secondary Gate Actuators to be PLC controlled.  Presently to operate these gates someone has go to the blower building and physically open and close the gate.  These operations are major safety hazards due to some of the weather conditions involved and must be eliminated.   In addition, in this phase, PDA will also introduce more signals to the SCADA system in the plant which are currently not visible.  The New HMI (Ignition) screens will be created to show the same data found on the existing legacy screens.  To minimize project scarring, and to conserve budget, PDA will be able to use the same tags and registers in the SCADA screens.  Facility Managers have options when working with PDA regarding SCADA screens. They can choose to mirror the existing screens to minimize operator change management, redevelop the screens to a new templated-based screen development allowing for ease of implementation across a SCADA system, or adopt new standards such as High-Performance HMI visualization. Any option that is chosen will undergo a thorough review of the screens as they are developed in the new platform. PDA hosts HMI workshops that promote functionality checks and review with the municipality as the screens are being developed to ensure that all parties are satisfied with the look/feel of the screens. Overall, these solutions will provide a better (safer) work environment.

No technical roadblocks have been encountered in Phase Two.  The largest challenge was to adapt the scope of the phase to meet the Authority’s approved budget.  PDA led open and iterative planning sessions with the client to triage the highest priority items into the budget allotment.

Future phases will include the upgrade of the control systems at each of the 28 locations.  Also, the installed fiber communication will allow direct control from SCADA to any of these remote sites. Finally, the original alarming notification was very basic. There was one person on the call list and the information provided on the call-out was vague.  The person had to go to the plant to see what the alarm was before addressing it. Now with the alarms going through the Ignition call out, the person who is at the top of the roster gets the exact description of the alarm and can travel directly to the location instead of having to go to the plant to determine the issue. At the end of the projects, the Authority will have a single source of information for their entire operations.  All necessary operations and notifications will be visible to those who need it, when they need it.

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