Automation of water treatment and delivery systems is essential to safety, reliability, and affordability. Successful automation system design requires understanding the many components of water systems - pumps, piping, valves, flow hydraulics, blowers, and unit treatment processes (such as biological treatment, filtration, disinfection.)
The automation system is assembled around the process. The instruments are the eyes and ears, providing feedback to the process control hardware, and keeping the operators informed if there is a need for intervention. This is typically documented through a Process and Instrumentation Diagram, a schematic drawing that begins with the process itself, then adds all the basic elements of the automation system. It provides unique identifying names to each element, allowing team members to have a common "language" during design development discussions.
As automation systems have evolved, more functionality has become embedded in software instructions and application configuration. For this aspect of automation, a Process Control Narrative describes in logically structured text how the automation system is to respond to instrument inputs, and interact with the operator through its Human-Machine Interface (HMI).
The Graton Community Services District tertiary process control system was designed while Ed was at Lescure Engineers, with the assistance of partner firms for mechanical and electrical engineering. The case study here summarizes the project.