Wastewater Plant 3 PLC Upgrade

The City of Bakersfield (City) needed immediate, emergency upgrades for PLC hardware and software at Wastewater Plant 3. PLC-7, which served the entire solids handling for the facility, had a Profibus DP communication card failure. This caused PLC-7’s associated automated valves to cease communication and work with automatic sequences.

Cannon was selected to provide a design-build upgrade of this facility and additional automation support services for other plant facilities. Cannon completed an on-site evaluation and troubleshooting to determine the key issues to be resolved. Review and evaluation included collecting network diagrams, security information, PLC panel drawings, loop diagrams, PLC logic, and SCADA applications.

During the project, we discovered the Centrifuge PLCs needed to be upgraded to provide a complete system overhaul. Cannon designed the upgrade from Modicon Quantum PLCs to Modicon M580 PLC (for PLC-7) and M340 PLCs (for 3 Centrifuge units). Cannon coordinated with Graybar/Schneider and used the UMAC conversion tool to validate the “cross functionality” required between the two platforms, including considerations for Global Data, Modbus Plus networks, and Profibus networks.

Cannon was successful in upgrading PLC-7 and Centrifuge PLCs on an accelerated schedule and quickly restoring the plant solids operation. These upgrades provided the City a modern, reliable, and supported platform with a 10-15-year expected operational lifespan.