Tank Filling & Monitoring SCADA Dashboard

A standalone SCADA/HMI dashboard built in FUXA, simulating a liquid storage tank fill/drain process. This project demonstrates core SCADA engineering concepts, tag architecture, analog level monitoring, safety interlocking, alarm states, and server-side process scripting — independent of any physical or virtual PLC.

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System Overview

The dashboard models a simple industrial tank system:

1. Fill Control: Starting the pump begins raising the tank level over time.
2. Analog Level Monitoring: A live level bar reflects the tank's fill percentage (0–100%).
3. High-Level Safety Interlock: When the tank reaches 90%, the system automatically stops the pump and raises a high-level alarm.
4. Low-Level Warning: When the tank drops to 10% or below, a low-level alarm is raised.
5. Status Feedback: A pilot lamp indicates whether the pump is actively running.

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Tag Architecture

Tag Name	Type	Purpose
Tank_Level	Number	Current fill percentage (0–100)
Pump_Status	Number	Pump running state (1 = running, 0 = off)
Drain_Valve	Number	Drain valve state
High_Alarm	Number	High-level safety alarm
Low_Alarm	Number	Low-level warning alarm
Start_PB	Number	Operator start command
Stop_PB	Number	Operator stop command
Tank_Rate	Number	Configurable fill/drain rate per cycle

All tags are internal to FUXA's own tag server — no external PLC or Modbus device is required, making this a fully self-contained simulation.

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Process Logic

A server-side JavaScript script (TankLogic) runs on a fixed interval and governs the simulation:

• Reads Start_PB / Stop_PB to determine operator intent
• Increments Tank_Level while Pump_Status is active
• Enforces a 90% high-level interlock: automatically stops the pump and raises High_Alarm
• Enforces a 10% low-level warning: raises Low_Alarm
• Resets momentary push-button tags after each action, mimicking real push-button behavior

This mirrors the same safety-interlock logic pattern used in the companion PLC-Conveyor-Control ladder logic project — translated from ladder rungs into an equivalent scripted state machine.

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Operator Interaction

Dashboard elements are tag-bound and update live from the underlying process state:

• Tank shape with proportional fill level indicator
• START / STOP buttons for operator control
• STATUS lamp reflecting real-time pump state

Note on interaction method: During development, a UI-layer click-event quirk in this FUXA build version was identified — button-triggered tag writes did not propagate through the same rendering path as direct tag writes (verified via server logs and browser console debugging). As a result, this dashboard is demonstrated using FUXA's built-in tag-force/test panel to drive tag states directly — a standard technique used in real SCADA commissioning and testing. All underlying process logic, safety interlocks, and visual bindings are fully functional and verified working; only the on-screen button's click handler is affected.

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Debugging & Engineering Process

Getting this dashboard fully operational involved substantial hands-on troubleshooting, including:

• Diagnosing a scripting API mismatch (getTagValue/setTagValue vs. FUXA's actual $getTag/$setTag functions) via server-side terminal error logs
• Identifying a data-type mismatch between boolean tags and numeric shape-fill rules, and resolving it by standardizing all discrete tags to numeric type
• Isolating a UI/script write-path inconsistency through systematic testing (manual tag force vs. scripted write vs. button click) and browser console inspection
• Managing script execution intervals to balance live simulation behavior against demo/documentation needs

This iterative diagnostic process — reading server logs, isolating variables, testing hypotheses one at a time — reflects the same troubleshooting discipline required when commissioning real industrial control systems.

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Dashboard States

Screenshots demonstrating the system across its key operating states are included in Documentation/screenshots/:

1. Rest state — tank empty, pump off
2. Pump running — status lamp active
3. Mid-fill — proportional level indication

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Industrial Design Considerations

• Fail-safe interlock: High-level condition unconditionally overrides pump command, regardless of operator input
• Separation of concerns: Process logic (script) is decoupled from visualization (tag-bound shapes), consistent with standard SCADA architecture
• Tag-based design: All logic operates on named tags rather than hardcoded values, allowing the same dashboard to be repointed to a real Modbus/OPC device with no visual changes

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Future Development

• Resolve the click-event binding quirk and restore full on-screen button control
• Connect to a real or virtual PLC via Modbus TCP (following the same pattern as the OpenPLC conveyor project)
• Add a historical trend chart for Tank_Level over time
• Add configurable fill/drain rates via the Tank_Rate tag
• Connect to a real or virtual PLC via Modbus TCP (following the same pattern as the OpenPLC conveyor project)
• Add a historical trend chart for Tank_Level over time
• Add configurable fill/drain rates via the Tank_Rate tag