REDUNDANCY-NEEDED IN YOUR CONTROL SYSTEM?

摘要

With the advent of relatively inexpensive automation systems, redundancy in treatment plants control systems is frequently misapplied. In too many cases, blanket assumptions are used during a plant's design, resulting in either too much redundancy applied at unnecessary cost, or a system designed with inadequate assurance that water quality will be maintained during the eventual failure of a critical portion of the control system. Part of the problem is the vast array of technical solutions both offered by vendors and created by designers. Under extreme pressure to increase effectiveness with less funding, municipalities have been trying to find ways to cut the cost of building new plants. Redundancy in control systems always seems like a luxury when it comes time to pay for a well-thought out redundancy design and the actual benefits of this design is months or even years off. To make more informed choices, water quality staff needs to understand the advantages and disadvantages of different redundancy choices within their process control system. The findings of this study will help treatment plant personnel understand the different redundancy solutions being offered by design engineering firms and the advantages and disadvantages to each. They will have the ability to participate in the design process, to question the solutions being offered, and ensure that the best solution that meets the plant's operational needs is used. Plant personal will no longer have to live with poor design decisions for decades after the plant is complete. The value-added guidance gained though this study will enable plant operators to influence the design decisions to meet their needs.