The PLC is the industrial computer at the heart of the system.

• Role: Executes the control logic programmed to manage the entire water cycle.
• Input Handling: Receives signals from sensors (e.g., pressure, flow, level, and quality sensors) providing real-time data on the system's status.
• Decision Making: Compares the input data against the desired setpoints (e.g., target tank level, desired pipe pressure).
• Output Control: Sends control signals to actuators like pumps, motorized valves, and chlorination units to maintain the required conditions.
• Example: If the reservoir level drops below 30%, the PLC activates the main pump. If the pressure exceeds a safety limit, the PLC commands a valve to partially close.

The HMI is the visualization and interaction point for human operators.

• Role: Translates the complex electrical signals and data from the PLC into an intuitive graphical display.
• Visualization: Displays the entire system layout, showing real-time parameters (e.g., pump status, tank levels, flow rates) using diagrams and graphs.
• Operator Control: Allows operators to manually adjust setpoints, start/stop pumps, override automated sequences, and acknowledge alarms.
• Alarm Management: Provides instant visual and audible alerts for faults, equipment failures, critical pressure drops (indicating leaks), or other deviations from safe operation.