Abstract
Background: Acid deposition is a transboundary environmental problem that demands a reliable and safe measurement system. Previous studies on the same chamber progressed from manual measurement to real-time IoT monitoring; however, they still lacked centralized supervision, automated safety mechanisms, and early detection of sensor faults.
Objective: This study aimed to develop and evaluate an integrated supervisory system that combines Occupational Health and Safety (OHS) management with condition-based maintenance for acid deposition monitoring.
Methods: The system was designed using a Software-in-the-Loop (SiL) architecture within the Siemens ecosystem, following the ISA-95 framework, and was subsequently evaluated through fault-injection scenarios.
Results: The system monitored pH, temperature, water level, and actuator status at 1-second intervals without communication failures or data loss. The safety module detected all three tested hazardous pH conditions below 5.6, resulting in a Probability of Detection (POD) of 100%. The maintenance module detected out-of-range values and triggered an emergency shutdown after three faults occurred within 60 seconds. Availability varied from 66% to 93%, depending on failure frequency and repair time, indicating that faster recovery and fewer repeated failures improved system reliability.
Conclusion: The findings indicate that integrating supervision, OHS management, and condition-based maintenance can strengthen the safety, traceability, and reliability of acid deposition monitoring. The main novelty lies in integrating these functions within a single SCADA architecture validated through Software-in-the-Loop simulation, providing a practical basis for safer environmental monitoring stations and subsequent field implementation.