GOLD COAST CITY COUNCIL - MOLENDINAR WATER PURIFICATION PLANT / Job No: #2642/2768
After issuing a public tender Gold Coast City Council (GCCC) appointed MPA to implement a plant process control system upgrade for their Molendinar Water Purification Plant (MWPP). The Council specified in their tender that a new, Y2K compliant, reliable and efficient SIEMENS control system was to be engineered and installed quickly and seamlessly in order to accommodate the 150 mega litres of water the plant processes daily. The new control system was to be integrated into most of the plant functions, and had to be highly automated, yet flexible enough to allow for the manual control of any aspect of the plant. It was essential that operator feedback provide clear and accurate details regarding chemical dosage, safety levels, and fault indicators, while also accommodating remote access to the plant for after hours and emergency monitoring. MPA designed and commissioned a Process Control System to upgrade and replace the existing centralized process controller with a distributed PLC and SCADA System. They also supplied and installed all the hardware, programmable logic controllers (PLCs), PCs, Profibus and Ethernet networks.
The new Process Control System is entirely networked from SIEMENS products. SIEMENS WinCC SCADA software is incorporated into the dual redundant servers and two clients (see diagram), contributing to flawless communications between the components. WinCC provides an informative Operator Interface that allows for faster and more accurate diagnosis of plant status. Control of the purification process is distributed through five powerful SIEMENS S7 PLCs that readily deal with diverse process sequences. These PLCs, which include expansion and remote I/O racks, are situated across the plant and are networked via Profibus (copper and fibre optic) to four existing SIEMENS S7- 300 PLCs.
Designed for ease of operation, with user-friendly SIEMENS components, the new control system provides many improved features, which guarantee the plants reliable performance.Software for the entire site is stored in one project file and PLCs can be programmed and monitored from any node on the Profibus network resulting in minimal down time and minimal loss of plant function. The new system also has a readily expandable control structure and easy interfaces to third party devices.
