An Open SCADA-Based Supervisory Architecture for an Experimental Reverse Osmosis System: Development and Functional Validation.

Recent studies demonstrate growing interest in supervisory systems based on open architectures, but existing implementations report fragmented combinations of functions and validation evidence. This study developed and functionally validated an open four-layer SCADA-based supervisory architecture for an experimental reverse osmosis (RO) system. Eleven commercial off-the-shelf sensors were integrated through ESP32-based acquisition, MQTT communication, a Raspberry Pi/Flask edge server, SQLite persistence, and a browser-based human-machine interface (HMI). Validation combined historian analysis, controlled functional scenarios, bidirectional configuration tests, service-recovery trials, and a 600 s edge-resource assessment. The historian contained 190,840 records covering all eleven tags, with values, states, units, and timestamps. Controlled tests verified coherent measurement-state processing, alarm persistence and acknowledgment, thermal-dependency handling, stopped-state logic, diagnosis, and HMI presentation. Valid configuration changes were confirmed by the ESP32, whereas an out-of-range coefficient was rejected without changing the active value. All backend, broker, communication-path, and edge-server recovery trials met predefined criteria, with median recovery times of 6.384, 1.312, 1.517, and 90.604 s, respectively. During the controlled workload, 6600 MQTT publications and 480 HTTP requests were processed without errors, and SQLite integrity was preserved. The results demonstrate integrated cross-layer operation under the tested conditions. The architecture did not implement automatic closed-loop control of pumps or valves. Metrological performance, cybersecurity, usability, and scalability were outside the validation scope.