Project Files of Coupled Tanks Level Control Lab Library for Proteus

COUPLED TANKS LEVEL CONTROL LAB LIBRARY FOR PROTEUS - V1.0 (a coupled-tanks lab with a pop-up)
Designed by The Engineering Projects
www.TheEngineeringProjects.com

IMPORTANT LINKS
Article (read it first - pictures, step by step, every feature explained):
  https://www.theengineeringprojects.com/2026/11/coupled-tanks-level-control-lab-library-for-proteus.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/coupled-tanks-proteus-library
The demo runs on our Arduino UNO V4.0 (included) - working LEDs, RESET and a
built-in serial monitor, no Virtual Terminal to wire - its own article:
  https://www.theengineeringprojects.com/2026/10/arduino-uno-library-for-proteus-v40.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
Coupled-Tanks-TEP-v1.0/
|-- Proteus Library Files/
|   |-- ArduinoV4TEP.LIB                              201.9 KB   TEP Arduino boards V4.0 (UNO) -> LIBRARY
|   |-- TEPTANKS.LIB                                   15.8 KB   the library -> LIBRARY folder
|-- Proteus Model Files/
|   |-- TEPARDUINO.DLL                                883.5 KB   the Arduino board model -> MODELS folder
|   |-- TEPTANKS.DLL                                  312.0 KB   the model -> MODELS folder
|-- Proteus Simulation/
|   |-- CoupledTanks-PI-ArduinoUnoV4.pdsprj            18.8 KB   the demo project
|   |-- Tanks_Demo.hex                                 18.1 KB   the demo firmware
|   |-- TEPARDUINO.DLL                                883.5 KB   copy of the board model
|   |-- TEPTANKS.DLL                                  312.0 KB   copy of the model
|-- Arduino Code/
|   |-- Tanks_Demo/Tanks_Demo.ino                       3.1 KB   the demo sketch (source of the .hex)
|-- README.txt                                        ~13.5 KB   this file
Total: 2.60 MB (unzipped). The C++ source code of the models is not included.

WHAT IS IT?
A coupled-tanks level control lab, seen from the front and drawn at true scale (112 x 198 mm) - our
own design, after the coupled-tank plants
of process control courses:
  * Two clear tanks one above the other on an aluminium column, 36 x 36 mm inside, levels 0 - 50 mm
    with an overflow at 50 mm. A 12 V pump
    in the base fills the top tank (tank 1) through a tube; tank 1 drains through a 4 mm orifice
    into tank 2 below, tank 2 through another
    into the reservoir. A 1.5 mm leak valve on tank 2; a level sensor under each tank; the pump's
    MOSFET, PWR and PUMP LEDs on the base.
  * The physics: the pump gives 1.2 mL/s per volt above 1.5 V (a 0.3 s lag); each tank A dh/dt = in
    - out, out = Cd a sqrt(2 g h)
    (Torricelli, Cd 0.62); the overflows; the leak (LEAK).
  * The sensors: 0.5 V + 80 mV per mm of water (4.5 V at 50 mm), with a little noise (NOISE).
  * Click it at Run for the pop-up: the tanks with their water and streams, the levels and the pump
    since the start, the linear model at
    the levels (the time constant, the gain, the voltage that holds them), PI gains for the tank-1
    loop (WN rad/s, zeta 0.8) and for a
    cascade on tank 2 (WN / 5, zeta 1), every level move measured (rise, overshoot, peak, settling)
    and the leak (the dip, the recovery).
The body is drawn as on the real part and to true scale against our Arduino.
The TEP signature and the pop-up are TEP additions.

ONE DEVICE (search "TANKS" in Pick Devices):
  COUPLEDTANKSTEP  "Coupled Tanks V1.0" in TEPTANKS.LIB (Control Labs > Process), prefix U, model
  TEPTANKS.DLL (mixed: digital + SPICE).
                   Pins 12V (the pump's supply), PWM (the pump MOSFET's gate), L1, L2 (the level
                   sensors), 5V (the sensors), GND - on the
                   base's left edge.

THE POP-UP
Click the part at Run. Tabs:
    Lab        the tanks (their water, the streams, the levels), both levels and the pump since the
    start, and eight live values: tank 1,
               tank 2, the pump, the outflows, the model, the tank-1 PI, the cascade and the last
               move (or the leak).
    Graphs     the live values over the last 2, 6 or 15 s. Live / Freeze.
    Event log  every change and warning; filters All / Changes / Warnings, Pause, Clear
    Check      what the part is doing and what to look at, each with a verdict (green = fine, amber
    = check, red = wrong)
    Settings   theme, text size, open at Run, window size
    Help       report a bug, suggest a feature, article, updates, donate, forum; Copy diagnostics
    for a bug report

TEST STATUS
V1.0: verified in Proteus 8.5 on 7 Nov 2026 (the demo project as shipped: an A4 sheet, an Arduino UNO V4.0).
What the runs showed (the model's own numbers and the sketch's monitor):
  * The project loads and starts cleanly; the demo runs 232 simulated seconds in about 12 minutes on
    our PC (the tanks are slow); the pump's
    PWM is 490 Hz.
  * The model at 25 mm: tau 11.9 s, 11.0 mm of level per volt, held by 6.05 V; the tank-1 PI for 0.6
    rad/s and zeta 0.8: Kp 0.946 V/mm,
    Ki 0.3888 V per mm.s; the cascade (0.12 rad/s, zeta 1): Kp 1.85, Ki 0.171 per s. At 41.6 mm: tau
    15.3 s, 14.2 mm/V, held by 7.36 V.
  * Tank 1 (PI with the feed-forward): 25.0 to 34.9 mm - rise 1.8 s, overshoot 11.3 %, peak at 4.0
    s, settled (5 %) in 6.2 s; 34.9 to
    25.0 mm - rise 1.9 s, overshoot 14.9 %, peak at 4.0 s, settled in 6.6 s.
  * Tank 2 (the cascade): 25.0 to 32.0 mm - rise 6.0 s, overshoot 19.8 %, peak at 18.9 s, settled (5
    %) in 40.5 s; tank 1 went to 31.9 mm
    to hold it.
  * The leak at 175 s (1.5 mm): tank 2 dipped from 32.00 to 29.77 mm (2.23 mm, lowest 8.8 s after)
    and was back within 0.3 mm in 43.5 s,
    tank 1 raised to 41.6 mm; no overflow. The pop-up: Lab, Graphs, Event log, Check - all four
    pages followed the run.

INSTALLATION (about 2 minutes)
1. Close Proteus. Extract the WHOLE ZIP to a normal folder (e.g. Desktop).
2. Copy everything in "Proteus Library Files" (TEPTANKS.LIB and our Arduino library V4.0,
ArduinoV4TEP.LIB, with the ARDUINO UNO V4.0 used by the demo) to the LIBRARY folder of Proteus, for
example:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\LIBRARY
   (use the folder that already holds Proteus's own .LIB files).
3. Copy TEPTANKS.DLL and TEPARDUINO.DLL from "Proteus Model Files" to the MODELS folder (...\Proteus
8 Professional\MODELS).
4. Delete TEPTANKS.IDX from the LIBRARY folder if it is there (Proteus makes a new index).
5. Start Proteus. In Pick Devices (P) search "TANKS".

RUN THE DEMO
"Proteus Simulation\CoupledTanks-PI-ArduinoUnoV4.pdsprj" (an A4 sheet) - keep the .hex file and the
DLLs beside the project.
  ARD1:   Arduino UNO V4.0 running Tanks_Demo.hex, its serial monitor built in (window "TEP Arduino
  UNO - ARD1").
  U1:     the coupled tanks (LEAK = 175 s): PWM - D9, L1 - A0, L2 - A1, 5V - VCC, 12V - a +12V
  terminal, GND.
  1. A PI with a feed-forward fills tank 1 to 25 mm, then steps it to 35 mm at 20 s and back to 25
  mm at 40 s.
  2. At 60 s a cascade takes over: an outer PI on tank 2 sets tank 1's target; tank 2 to 25 mm, then
  32 mm at 110 s.
  3. At 175 s the leak valve on tank 2 opens; the cascade raises tank 1 to make up for it.
Closed the monitor? Click the UNO's USB port.

WIRING (the same in Proteus and on a real board)
  PWM: a PWM pin (D9); L1, L2: two analog pins; 5V and GND; 12V: a supply that can give 0.5 A (the
  pump).
REAL HARDWARE:
 * Keep the electronics away from the water: a real rig drips, and the pump's leads see 12 V.
 * Real orifices clog and real sensors drift: calibrate the sensors with the tanks empty and full.
 * Air in a pump stops it pumping: prime it, and keep its intake under the reservoir's water.
 * The overflows are not optional on a real rig: a controller that saturates will fill a tank to the
   brim.

THE DEMO SKETCH ON THE SERIAL MONITOR (Tanks_Demo V1.0, 9600 baud)
There are no commands. The sketch fills tank 1, steps it, switches to the cascade, steps tank 2,
rides out the leak, and prints every 5 s.
EXPECTED MONITOR OUTPUT
  Coupled Tanks - The Engineering Projects
  t=150 s: tank1 31.9 mm, tank2 32.5 mm, pump 6.64 V
  t=230 s: tank1 41.6 mm, tank2 31.9 mm, pump 7.43 V

PROPERTIES (double-click the part > Edit Properties)
  Tank 1 at the start (LEVEL1)         mm of water in the top tank
  Tank 2 at the start (LEVEL2)         mm of water in the bottom tank
  Sensor noise (NOISE)                 mV RMS on L1 and L2
  Loop speed (WN)                      rad/s: the pop-up's tank-1 PI is for this speed and zeta 0.8;
  its cascade for WN / 5
  The leak (LEAK)                      the leak valve on tank 2 opens at this time in seconds; 0 =
  never
Every run starts again from the properties.

LINKS.INI (OPTIONAL)
The Help page cards of the pop-up open web pages. To point them somewhere else without a new DLL,
put a text file named links.ini next to TEPTANKS.DLL with lines KEY=URL, for example:
  ARTICLE=https://www.theengineeringprojects.com/...
Keys: WEBSITE, FORUM, BUG_REPORT, FEATURE_REQUEST, ARTICLE, USER_GUIDE,
UPDATE_CHECK, DONATE. Only http:// and https:// links are used; lines starting
with # are comments.

TROUBLESHOOTING
* NO 12 V: the gate is driven but 12V is missing - the pump cannot run.
* OVERFLOW: a tank is at 50 mm and spilling - the target is too high, or the loop's sign is wrong (a
  level too low must raise the pump).
* The levels read wrong: 5V is missing (L1 / L2 at 0 V), or the sketch's scale is not 0.5 V + 80 mV
  per mm.
* Tank 2 swings slowly around its target: the cascade's outer loop is too fast for the inner one -
  slow it down.
* The part is not simulated: TEPTANKS.DLL is missing from MODELS and from the project folder. No UNO
  / no monitor window: TEPARDUINO.DLL is missing, or click the UNO's USB port.

BUG REPORTS AND FEATURE REQUESTS
Please post them in our forum with a screenshot, the Serial Monitor text, the
simulation log and the pop-up's Copy diagnostics text:
  https://www.theengineeringprojects.com/forum/category/coupled-tanks-proteus-library

SUPPORT US
This library is free. If it saves you time, please support our work:
  https://www.theengineeringprojects.com/donate

WEBSITE
  https://www.theengineeringprojects.com/

LICENCES AND THIRD-PARTY NOTES
* The model (TEPTANKS.DLL), the symbols and artwork, the other parts of ours in the demo and the
  Arduino Library V4.0 (ArduinoV4TEP.LIB / TEPARDUINO.DLL, with its built-in TEP Serial Monitor
  Advance) are made by The Engineering Projects. The models use only standard Windows libraries; no
  Visual C++ redistributable is needed.
  The C++ source code is not included.
* Arduino UNO V4.0 (ArduinoV4TEP.LIB / TEPARDUINO.DLL, our Arduino Library V4.0 - its
  microcontroller is Proteus's own AVR model): The Engineering Projects,
  https://www.theengineeringprojects.com/2026/10/arduino-uno-library-for-proteus-v40.html
* The .hex file is built from the demo sketch and the Arduino AVR core 1.8.6, which includes
  LGPL-licensed code; its source code is available at
  https://github.com/arduino/ArduinoCore-avr/tree/1.8.6
* Proteus is a product of Labcenter Electronics and is not included. Arduino is a trademark of Arduino SA.
  This library is not made or endorsed by Arduino or Labcenter.

REBUILDING THE FIRMWARE (OPTIONAL)
The HEX file is supplied; Arduino IDE is not needed to run the demo. To edit the sketch, open
Arduino Code\Tanks_Demo\Tanks_Demo.ino, select Arduino Uno and use Sketch > Export Compiled Binary.
Replace the simulation's .hex with the exported HEX. The sketch needs 6,584 bytes of flash and 392
bytes of RAM.

MODEL SCOPE AND LIMITS
Modelled: the pump's flow and lag, Torricelli outflows through both orifices and the leak, the
overflows, the sensors' scale and noise, the
pump's and the sensors' supply currents.
Not modelled: the water's inertia in the tubes, waves and splashing, the sensors' temperature drift,
the reservoir running dry.

VERSION
TEP Coupled Tanks library V1.0 (Nov 2026). Device COUPLEDTANKSTEP (TEPTANKS.LIB / TEPTANKS.DLL).
Demo sketch Tanks_Demo V1.0. Demo board: ARDUINO UNO V4.0 (TEP Arduino Library V4.0) with its
built-in serial monitor.