PLC Renewal Design Assistance and Construction Support

The Metropolitan Council Environmental Services (MCES) PLC Renewal project developed a systematic, replicable template for replacing aging programmable logic controllers (PLCs) across facilities of varying sizes. This approach not only safeguards ongoing operations but also provides a detailed roadmap for utilities seeking to upgrade their control systems efficiently and reliably.

The Carollo team began with the creation of a comprehensive project delivery plan. This blueprint documents how consensus was achieved among team members, identifies the specialized field teams, and outlines how work will progress without disrupting facility functions. A core element of this plan is the establishment of standardized protocols for both PLCs and human-machine interfaces (HMIs) so that every upgrade adheres to a common set of guidelines.

During the design phase, Carollo conducted extensive field investigations to capture the as-found conditions of existing panels. The results of these investigations informed the development of updated hardware and software designs, along with thorough supporting documentation such as process control narratives, cutover plans, and detailed programming for PLCs and HMIs. With these documents in hand, the implementation phase commenced. Here, MCES electricians and Process Computer Group staff worked in unison to convert the panel hardware and software, followed by a series of tests and the full commissioning of the new systems. Final documentation was assembled to cement the changes and provide a resource for future maintenance and troubleshooting.

A pivotal component of the project involved a pilot program that replaced five PLCs selected for their diverse complexity. This initial foray identified potential challenges and offered insights that the team used to refine the process ahead of a larger, five-year rollout. To manage such a multifaceted undertaking, the team was divided into breakout groups focusing on project management, panel design, PLC and HMI programming, and testing and commissioning. Regular quality assurance and quality control reviews, along with continuous lessons learned sessions, made sure that each phase met stringent standards and that any necessary modifications were implemented in real time.

Demonstrating the capabilities of in-house systems integration, this project stands as a model for utilities looking to modernize without compromising operational integrity.