Protocol Reference¶

Growatt inverters use three distinct Modbus protocol families. Knowing which protocol your inverter uses tells you which register ranges are valid and what the integration will attempt to read.

Protocol Families¶

Protocol	Register Range	Inverter Families
Modbus RTU V1.39	0–124, 875–999, 1000–1124, 2000–2124, 3000–3374, 8000–8139	MIN, MOD, MID, MAX, MAC, SPH, SPA, WIT, WIS
VPP Protocol	30000–32000+	SPH, MIN TL-XH, MOD TL3-XH, MID TL3-XH, WIT, WIS
Off-Grid V0.26	0–97	SPF, SPE

Which Protocol Does My Inverter Use?¶

Most inverters use Modbus RTU V1.39 as the base protocol. Newer models that support VPP also respond to both — the integration reads both ranges and merges the data.

Inverter startup detection:
1. Try holding register 30000 (DTC code)
   → Success: VPP-capable inverter (also reads V1.39 registers)
   → Failure: Legacy-only inverter (V1.39 or Off-Grid only)

2. If legacy-only, check register range pattern:
   → Responds on 0-124: MIN, SPH, or Off-Grid family
   → Off-Grid protocol (0-97 only): SPF or SPE inverters

Register Ranges at a Glance¶

Range	Protocol	Content
0–124	V1.39	Base holding and input registers (all models)
875–999	V1.39	WIT commercial registers
1000–1124	V1.39	SPH/SPA storage control
2000–2124	V1.39	SPA extended (single-phase AC storage)
3000–3374	V1.39	MIN/MOD extended data
8000–8139	V1.39	WIT battery registers
30000–30099	VPP	Device ID, rated parameters
30100–30499	VPP	Control (AC power, battery, TOU schedule)
31000–31499	VPP	Real-time status, PV, grid, battery, load

Universal Register Scanner¶

The Universal Register Scanner action (Settings → Tools → Actions → growatt_modbus.export_register_dump) scans every range listed above and reports which registers your inverter actually responds to. This is the quickest way to verify protocol support and collect data for a new model.

See Diagnostic Actions for usage instructions.

Firmware builds¶

The build string on the inverter's device page (e.g. AL1.0 (ALBA18010122), from V1.39 holding registers 82-87) names more than one firmware. A MIN TL-XH update package holds two images for two processors: ALBA for the power-control processor and ZABA for the communication processor, flashed in that order. That is why ShinePhone shows those updates as two stages. @l4m4re's firmware analysis has the details. It is background only: this integration does not use anything from the firmware, and none of it is a reason to flash an inverter.