VSD system optimization

Overview This project restores normal operation of the distribution pump and VSD system so it works properly. Before, all field logic was controlled centrally by an Allen-Bradley (AB) PLC. To improve performance and operational focus, the team modified the system by separating a dedicated control panel for distribution/pumps and VSD from the main system.

Challenges

• Migrating a live system: Separate the pump and VSD control logic from the existing central (AB) PLC program without disturbing other functions that remain on that PLC.

• Multi-vendor integration: Make sure the existing AB PLC, the new Siemens S7-1200 PLC and the Vijeo Citect v7 SCADA communicate and stay in sync.

Solutions

• Added a dedicated panel: Installed a new PLC panel with a Siemens S7-1200, dedicated to the distribution system workload (pumps & VSD).

• Reprogramming across platforms: Modified the AB PLC program to release the pump functions, and wrote new control logic on the Siemens 1200 PLC.

• SCADA update: Reconfigured the tags, communication and HMI graphics in the Vijeo Citect v7 SCADA so operators can control this decentralized architecture smoothly.

Lessons learned Decentralizing the control of critical systems (such as pumps and VSD) into separate panels (dedicated controller) proved very effective for restoring the system. It reduces the processing load on the main PLC and makes troubleshooting and maintenance much easier later. Devices from different brands (AB and Siemens) can work well together if the network design and the SCADA configuration are done correctly.