Waterworks modernisation

While the process at the plant is fairly simple, the water industry likes to ensure a robust and reliable service to its customers, so designing redundancy in the control systems was an early decision.

In fact, the architecture of the final design provided a system that comprises of two pairs of redundant Mitsubishi Electric Q25 programmable logic controllers (PLCs) in the main works and a Q06 PLC in the pumping station. Each redundant system has two central processor units (CPUs) and a mix of traditional I/O and remote I/O. The remote I/O is connected in a number of different networks, some using fibre optic MELSECNet/H and others using Profibus.