Toward Edge Implementation of Soft Sensors for Water Distribution Networks

Fotis N. Koumboulis, Nikolaos D. Kouvakas, Maria P. Tzamtzi, Dimitrios G. Fragkoulis, Antonios N. Menexis, Klimis K. Katsiavrias, Konstantinos Katsiavrias, John Dimitropoulos

This paper presents an edge-oriented implementation of a discrete-time bank of switching observers for chlorine estimation in a benchmark water distribution network (WDN). The approach combines local execution of multiple observers within a Node-RED runtime, deterministic data acquisition from a programmable logic controller (PLC) via Modbus Transmission Control Protocol (TCP), and cloud-supervised switching. The architecture enables parallel observer execution, telemetry arbitration across a single stream, and continuous adaptation of the runtime. The experimental validation is carried out in a hardware-in-the-loop setup in which a hydraulic and quality simulated model provide the measurement data for a physical PLC in real-time, allowing to assess the entire edge–cloud pipeline under realistic conditions of an industrial communication system.