# MPPT Testbench

Unified CLI tool for testing MPPT (Maximum Power Point Tracking) converters using three coordinated instruments:

| Instrument | Role | Interface |
|---|---|---|
| **ITECH IT6500D** | DC power supply (solar panel simulator) | USB-TMC / SCPI via PyVISA |
| **Prodigit 3366G** | DC electronic load (600V/420A/6kW) | RS-232 (115200 8N1 RTS/CTS) |
| **HIOKI 3193-10** | Power analyzer (efficiency measurement) | GPIB via UsbGpib / PyVISA |

## Wiring

```
                        ┌──────────────────┐
  IT6500D  ──(+/-)──>   │   MPPT Tracker   │  ──(+/-)──>  Prodigit 3366G
                        │      (DUT)       │
  HIOKI Ch5 ──(sense)── │  Input    Output │ ──(sense)──  HIOKI Ch6
                        └──────────────────┘

  HIOKI EFF1 = P6 / P5 x 100%  (output power / input power)
```

## Installation

Requires Python 3.12+, NI-VISA runtime, and `uv`.

```bash
git clone --recurse-submodules https://git.b4l.co.th/B4L/mppt-testbench.git
cd mppt-testbench
uv venv
uv pip install -e .
```

## Quick Start

```bash
# 1. Check all instruments are connected
mppt identify

# 2. Configure everything for MPPT testing
#    (sets wiring, coupling, auto-range, efficiency formula, display)
mppt setup

# 3. Take a single reading from all instruments
mppt measure

# 4. Continuous monitoring with CSV export
mppt monitor --interval 1.0 --output data.csv

# 5. Live real-time graph (Power, Efficiency, Voltage, Current)
mppt live --interval 0.5
```

## Sweep Commands

### Voltage Sweep

Sweep supply voltage across a range while the load is held constant. Records efficiency at each point.

```bash
mppt sweep \
  --v-start 30 --v-stop 100 --v-step 5 \
  --current-limit 10 \
  --load-mode CC --load-value 3.0 \
  --settle 2.0 \
  -o voltage_sweep.csv
```

After the sweep, the supply returns to 75V and stays ON.

### Load Current Sweep

Sweep load current (CC mode) at a fixed supply voltage.

```bash
mppt sweep-load \
  --voltage 75 --current-limit 10 \
  --i-start 0.5 --i-stop 8 --i-step 0.5 \
  --settle 2.0 \
  -o load_sweep.csv
```

After the sweep, the load turns OFF and the supply returns to 75V (stays ON).

### Auto-Range Handling

The HIOKI 3193-10 returns special error values (`+9999.9E+99`) while auto-ranging. The testbench automatically waits for all measurement channels to settle before recording each sweep point. The supply is kept alive with periodic queries during the wait to prevent USB-TMC timeouts.

## Direct Instrument Control

```bash
# Supply
mppt supply set --voltage 48 --current 10
mppt supply on
mppt supply off

# Load
mppt load set --mode CC --value 5.0
mppt load set --mode CR --value 10.0
mppt load on
mppt load off

# Emergency shutdown (load first, then supply)
mppt safe-off
```

## Efficiency Measurement

Measure averaged efficiency at a fixed operating point:

```bash
mppt efficiency \
  --voltage 75 --current-limit 10 \
  --load-mode CC --load-value 3.0 \
  --samples 10 --settle 3.0
```

## CLI Reference

```
mppt [-h] [--supply-address ADDR] [--load-port PORT] [--load-baud BAUD]
     [--meter-address ADDR] [--timeout MS]
     {identify,setup,measure,monitor,live,sweep,sweep-load,efficiency,
      supply,load,safe-off}
```

| Command | Description |
|---|---|
| `identify` | Show identity and status of all instruments |
| `setup` | Configure all instruments for MPPT testing |
| `measure` | Single measurement from all three instruments |
| `monitor` | Continuous text monitoring with optional CSV |
| `live` | Real-time 4-panel matplotlib graph |
| `sweep` | Voltage sweep with efficiency recording |
| `sweep-load` | Load current sweep at fixed voltage |
| `efficiency` | Averaged efficiency at a fixed operating point |
| `supply` | Direct IT6500D control (on/off/set) |
| `load` | Direct Prodigit 3366G control (on/off/set) |
| `safe-off` | Emergency shutdown (load first, then supply) |

### Global Options

| Option | Default | Description |
|---|---|---|
| `--supply-address` | auto-detect | IT6500D VISA address |
| `--load-port` | `COM1` | Prodigit 3366G serial port |
| `--load-baud` | `115200` | Prodigit 3366G baud rate |
| `--meter-address` | auto-detect | HIOKI 3193-10 VISA address |
| `--timeout` | `5000` | VISA timeout in milliseconds |

## CSV Output Format

Sweep CSV files contain the following columns:

| Column | Description |
|---|---|
| `voltage_set` | Supply voltage setpoint (V) |
| `current_limit` | Supply current limit (A) |
| `load_setpoint` | Load setpoint value (A for CC mode) |
| `supply_V/I/P` | Supply measured voltage, current, power |
| `load_V/I/P` | Load measured voltage, current, power |
| `input_power` | HIOKI P5 -- power into MPPT tracker (W) |
| `output_power` | HIOKI P6 -- power out of MPPT tracker (W) |
| `efficiency` | HIOKI EFF1 -- P6/P5 x 100 (%) |

## Setup Details

`mppt setup` configures the instruments as follows:

- **Supply**: Remote control mode
- **Load**: Remote control mode
- **Meter**:
  - Wiring: 1P2W
  - Ch5 (solar input): DC coupling, voltage and current auto-range
  - Ch6 (MPPT output): DC coupling, voltage and current auto-range
  - Response speed: SLOW (best accuracy)
  - EFF1 = P6 / P5 (output / input)
  - Display: 16-item SELECT view -- U5, I5, P5, EFF1 (left) | U6, I6, P6 (right)

## Project Structure

```
mppt-testbench/
├── IT6500D/              git submodule - DC power supply driver
├── PRODIGIT-3366G/       git submodule - electronic load driver
├── HIOKI-3193-10/        git submodule - power analyzer driver
├── testbench/
│   ├── __init__.py       exports MPPTTestbench
│   ├── bench.py          orchestrator (sweeps, measurement, auto-range wait)
│   └── cli.py            unified CLI entry point
└── pyproject.toml        package config, entry point: mppt
```

## Dependencies

- Python >= 3.12
- [PyVISA](https://pyvisa.readthedocs.io/) + [pyvisa-py](https://pyvisa.readthedocs.io/projects/pyvisa-py/)
- [pyserial](https://pyserial.readthedocs.io/)
- [matplotlib](https://matplotlib.org/)
- NI-VISA runtime (for GPIB/USB-TMC communication)