franklinwh-modbus 0.9.2

FranklinWH aGate Modbus TCP library — SunSpec + extension registers

franklinwh-modbus

A Python library for controlling FranklinWH battery storage systems via Modbus TCP, optimized for the aGate gateway with SunSpec model support and FranklinWH extension registers.

📖 New to Modbus TCP? See the documentation site for an introduction to Modbus TCP, SunSpec, and how this library compares to the Cloud API.

Note: This is the Modbus TCP library (pip install franklinwh-modbus).

Python import: from franklinwh_modbus import FranklinWHController

For the non-Modbus TCP FranklinWH david2069 franklinwh-cloud Cloud API, see franklinwh-cloud.

For the non-Modbus TCP FranklinWH richo franklinwh-python Cloud API, see franklinwh-python.

Status: Core library under active development, targeting PyPi publication.

Quick Links

• 🚀 Getting Started — setup, install, CLI, network scanner & SunSpec reader
• 📖 Library & CLI Usage Guide
• 📚 Documentation
• 🧪 Hardware Test Guide
• 📝 Changelog

⚠️ Important — Before You Start

Network Requirements

• Fixed IP address required — the aGate must have a static/reserved IP on your LAN.
• LAN Ethernet strongly preferred — wired connection for reliable Modbus TCP control.
• ⚠️ WiFi is highly undesirable — latency and packet loss can cause missed keep-alive cycles, leaving the aGate stuck in VPP Mode.

Extension Register Access

Read operations always work — battery status, grid power, solar production (proximal and remote), system alarms, and all SunSpec model data are readable by any Modbus TCP client without provisioning. The CLI --status, --healthcheck, and TUI monitor all work out of the box.

Write access to extension registers (15507–15509: OnGridMode, SelfReserve, TOUReserve) requires "SPAN Modbus" unlock in FranklinWH installer settings.

Already qualified: Owners with SPAN Panels or Lumin Panels connected to the aGate via Modbus TCP — these systems already have full write access enabled.

Not yet provisioned? Contact FranklinWH Support to request Modbus write access for your aGate. Without provisioning, extension registers are read-only (writes fail silently). Note: Standard SunSpec M704 power commands (charge/discharge) work regardless of SPAN unlock status.

Avoiding Control Conflicts

[!CAUTION] Do not use the FranklinWH mobile app to send charge/discharge commands or schedule events while this library is actively controlling the aGate. Conflicting commands will cause unpredictable behavior.

• Recommended: Set your aGate to Emergency Backup or Self-Consumption mode via the mobile app before starting library control — this reduces the likelihood of conflicting Cloud API activity.
• VPP Mode indicator: While any remote client API is actively controlling the aGate — Modbus TCP (this library) or the FranklinWH Cloud API (VPP providers) — the mobile app displays "VPP Mode". This is normal and confirms direct control is active. See VPP Mode Visual Reference for mobile app screenshots.
• On failure or loss of connectivity: Always release control using --stop:

# Via CLI
python3 franklinwh_cli.py -i YOUR_AGATE_IP --stop

# Via library
ctrl.reset_control_state()
ctrl.disconnect()

[!WARNING] If control is not released, the aGate persists the last command indefinitely. Hardware heartbeat (ControllerHb) and reversion timer (WSetRvrtTms) do not work on FranklinWH — use --revert N or send_command(cmd, duration_s=N) for software-side auto-revert.

Installation

git clone [e-mail]:david2069/franklinwh-modbus.git
cd franklinwh-modbus
python3 -m venv venv && source venv/bin/activate
pip install -e ".[dev]"

Library Usage

from franklinwh_modbus import FranklinWHController, BatteryCommand

# Connect to aGate
ctrl = FranklinWHController('YOUR_AGATE_IP')
ctrl.connect()

# Read battery status (battery_state derived from DC power, not unreliable M713.Sta)
status = ctrl.read_battery_status()
print(f"SoC: {status['soc']:.1f}%  State: {status['battery_state']}")

# Charge at 3000W with 1-hour software timeout (auto-reverts to cloud control)
cmd = BatteryCommand(power_watts=3000, mode='charge')
ctrl.send_command(cmd, duration_s=3600)

# Release control (or let timeout handle it)
ctrl.reset_control_state()
ctrl.disconnect()

CLI Quick Start

# System status
python3 franklinwh_cli.py -i YOUR_AGATE_IP --status

# Health check with conflict detection
python3 franklinwh_cli.py -i YOUR_AGATE_IP --healthcheck

# Charge at 3000W with auto-revert after 2 hours
python3 franklinwh_cli.py -i YOUR_AGATE_IP --charge 3000 --revert 7200

# Self-consumption mode
python3 franklinwh_cli.py -i YOUR_AGATE_IP --mode self_consumption --target-soc 90

# Terminal UI monitor (requires `rich`)
python3 franklinwh_cli.py -i YOUR_AGATE_IP --monitor

# Release control
python3 franklinwh_cli.py -i YOUR_AGATE_IP --stop

Key Features

Feature	Description
Modbus TCP	Direct register read/write via pymodbus
SunSpec Models	Models 1, 701-706, 713-715
FranklinWH Extensions	Registers 15507-15509 (OnGridMode, reserves)
Virtual Modes	Self-Consumption, Emergency Backup, TOU, Peak Shave, Manual
Conflict Detection	Detects aGate Cloud API activity before taking control
SoC Safety	Reserve validation, target checking, safety margins
Alarm Monitoring	System, DC port, battery, solar alarms
Auto-Revert	Software timeout (hardware reversion non-functional on FranklinWH)

Project Structure

franklinwh-modbus/
├── src/franklinwh_modbus/          # Core library (the package)
│   ├── controller.py        # FranklinWHController — Modbus interface
│   ├── modes.py             # VirtualModeController — control modes
│   ├── types.py             # BatteryCommand, VirtualMode, enums
│   ├── schedule.py          # TOUSchedule — time-of-use
│   ├── monitor.py           # CLIMonitor — TUI (optional, needs rich)
│   └── constants.py         # Register addresses, limits
├── tools/franklinwh_cli.py   # CLI tool (consumes the library)
├── tests/                   # Unit + integration + hardware tests
├── docs/                    # Documentation
├── tools/                   # Utility scripts
└── schedules/               # TOU schedule definitions

Supported Hardware

Model	Status	Notes
FranklinWH aPower	✅ Full Support	Battery storage
FranklinWH aGate	✅ Full Support	Communication gateway

SunSpec Model Support

Note: aGate uses base address 1 (not standard 40000). Unit ID 1 or 2 both work (DA=1).

Model	Description	Read	Write	Notes
1	Common	✅	❌
701	DER AC Measurements	✅	❌
702	DER DC Measurements	✅	❌
703	DER Capacity	✅	❌
704	DER AC Battery Control	✅	✅	WSetPct/WSetEna confirmed working
705	DER AC Controls	✅	⚠️	Untested
706	DER Volt/Var/Watt	✅	⚠️	Untested
713	DER Storage Capacity	✅	❌	⚠️ Sta always 0 (unreliable)
714	DER Storage Status	✅	❌	DCW used for battery state derivation
715	DER Storage Controls	✅	❌	LocRemCtl read-only, heartbeat non-functional

FranklinWH Extension Registers

Register	Address	Access	Description
OnGridMode	15507	R (RW with SPAN)	0=Backup, 1=TOU, 2=Self-Consumption, 3=Manual
Self Reserve SOC	15508	R (RW with SPAN)	Self-consumption reserve percentage (0-100)
TOU Reserve SOC	15509	R (RW with SPAN)	⚠️ Known defect: always mirrors 15508

See FRANKLINWH_SUNSPEC_QUIRKS.md for all documented hardware quirks.

Contributing

See CONTRIBUTING.md for development setup and guidelines.

License

MIT License — see LICENSE for details.

Support

• 🐛 Report a Bug
• 💡 Request a Feature
• 📖 Documentation