Huawei SUN2000

Modbus TCP

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Last updated: 03. 2026

Huawei FusionSolar

The Huawei SUN2000 3-10KTL series are single-phase and three-phase string inverters for residential PV systems, with rated power from 3 kW to 10 kW. TapHome connects to the inverter via Modbus TCP — either directly through the inverter’s built-in WiFi access point or through a Huawei Smart Dongle (WLAN-FE or LAN) connected to the local network.

The template provides active power monitoring, DC input power, PV string current and voltage readings for up to 4 strings, daily and cumulative energy counters, detailed inverter status with alarm decoding, battery storage overview (for LUNA2000), and power control actions including reactive power compensation and active power derating.

Enabling Modbus communication

The SUN2000 inverter supports Modbus TCP over its WiFi access point and through the Smart Dongle. For a permanent connection with TapHome, the recommended approach is using a Huawei Smart Dongle-WLAN-FE (or Smart Dongle-4G) plugged into the inverter’s USB port.

Connection options

Method	Interface	Notes
Smart Dongle (recommended)	Ethernet / WiFi	Connects inverter to local LAN. Allows simultaneous Modbus TCP + FusionSolar app.
WiFi Access Point	WiFi	Direct connection to inverter AP (SSID: `SUN2000-<serial>`). Only one client at a time.
RS-485 (Modbus RTU)	COM port pins RS485A1/B1	Not used by this template. Cannot run simultaneously with FusionSolar monitoring.

When using the WiFi Access Point method, the FusionSolar app cannot connect simultaneously. For production installations, always use the Smart Dongle so that both TapHome and FusionSolar can operate at the same time.

Smart Dongle setup

Plug the Smart Dongle-WLAN-FE into the USB port on the bottom of the inverter
Connect the Smart Dongle to the local WiFi network using the FusionSolar app (initial setup)
The dongle will obtain an IP address from the router via DHCP
Note the IP address from the router’s DHCP lease table

Assign a static IP address to the Smart Dongle in the router’s DHCP settings to prevent the address from changing after a power cycle.

Network connection

Protocol: Modbus TCP
Port: 502 (standard Modbus TCP port)
Default Slave ID: 1
Byte order: Big-endian (standard Modbus)

The Huawei Home Assistant integration uses port 503 by default (WiFi AP mode). When connecting through the Smart Dongle on a local network, TapHome uses the standard Modbus TCP port 502.

Configuration

When importing the template in TapHome, provide:

IP Address — the Smart Dongle’s IP on the local network (or the inverter’s WiFi AP IP, default: 192.168.200.1)
Slave ID — Modbus slave address (default: 1)

Device capabilities

The template exposes the following devices:

Active Power

An electricity meter device that reads the inverter’s current AC output. This is the primary power monitoring device.

Active power — current AC output power in kW (register H:32080, Int32)
Power factor — grid power factor (register H:32084, Int16)
Peak active power of day — highest power output today in kW (service attribute, H:32078)
Reactive power — current reactive power in kVar (service attribute, H:32082)
Rated power / Max active power / Max apparent power — nameplate ratings from registers H:30073, H:30075, H:30077

The device also provides three service actions for power control:

Reactive power compensation (PF) — set power factor from -1.0 to 1.0 (writes to H:40122)
Reactive power compensation (Q/S) — set reactive power ratio (writes to H:40123)
Active power derating (%) — limit output power as percentage 0–100% (writes to H:40125)

DC Input Power

Read-only sensor showing total DC power input from all PV strings combined, in kW (register H:32064, Int32, divided by 1000).

Service attributes show grid-side details: grid frequency (H:32085), phase voltages A/B/C (H:32069–32071), and phase currents A/B/C (H:32072–32076).

Battery

A container device for battery storage status (Huawei LUNA2000). Shows:

Running Status — Offline, Standby, Running, Fault, or Sleep mode (H:37762)
Current Day Charge — energy charged today in kWh (H:37784)
Current Day Discharge — energy discharged today in kWh (H:37786)

The Battery device only appears functional when a LUNA2000 battery is connected to the inverter. Without a battery, the running status will show “Offline”.

Total Energy

Cumulative energy generated since commissioning, in kWh (register H:32106, UInt32, divided by 100).

Daily Energy

Energy generated today, in kWh (register H:32114, divided by 100).

PV string currents (PV1–PV4)

Four separate sensor devices, one per PV string, reading DC current in amps (registers H:32017, H:32019, H:32021, H:32023). Each device includes a service attribute for the corresponding string voltage (H:32016, H:32018, H:32020, H:32022).

The number of active PV string devices depends on the inverter model and installation. Unused strings will read 0 A.

Inverter Status

A multi-value switch (read-only) showing the inverter’s current operating state from register H:32089:

Value	State	Description
0	Inverter State	Initial / unknown
1	Idle	Detecting ISO, irradiation, or grid
2	Starting	Inverter starting up
3	On Grid	Normal power generation
4	Shutdown	Fault, command, OVGR, or DC switch off
5	Grid Dispatch	cos(Phi)-P or Q-U curve active
6	IV Scanning	PV string I-V curve scanning
7	Spot-Check	Grid spot-check in progress
8	Inspecting	Inspection mode
9	DC Input Detection	Detecting DC input

Service attributes provide detailed state information:

Full State — expanded status with all sub-states (e.g., “Shutdown: Fault”, “On-Grid: Power Limit”)
Grid Connection — standby, normal, derating due to power rationing or internal causes
Teleindication — IEC104 telesignaling state
Locking Status / PV Connection Status — from monitoring register H:32002
Startup time / Shutdown time — last startup and shutdown timestamps

Alarm monitoring

The module-level read script monitors alarm registers H:32008 and H:32009 (Bitfield16). Each bit maps to a specific fault or warning:

Register	Bit	Alarm
H:32008	0	High String Voltage
H:32008	1	DC Arc Fault
H:32008	2	String Reversed
H:32008	3	Abnormal String (warning)
H:32008	7	Power Grid Failure
H:32008	8–9	Grid Under/Overvoltage
H:32008	11–13	Grid Frequency Faults
H:32008	14–15	Output Overcurrent / DC Component
H:32009	0	Abnormal Leakage Current
H:32009	1–2	Ground / Insulation Faults
H:32009	3–4	High Temperature / Equipment Fault
H:32009	9	Abnormal Energy Storage Device
H:32009	10–11	Active/Passive Islanding

Module-level diagnostics

The module exposes service attributes for device identification and diagnostics:

Attribute	Register	Description
Model Name	H:30000	Inverter nameplate model
SN	H:30015	Serial number
PN	H:30025	Product code
Model ID	H:30070	Numeric model identifier
Number of Strings	H:30071	Connected PV strings
MPPT Number	H:30072	MPP tracker count
System Time	H:40000	Inverter local time
Time Zone	H:43006	UTC offset
Inverter Efficiency	H:32086	Conversion efficiency (%)
Cabinet Temperature	H:32087	Internal temperature
Insulation Resistance	H:32088	PV array insulation
DSP Data Collection	H:32002	Data collection status

A Time Zone service action allows setting the inverter’s UTC offset (writes to H:43006).

Additional capabilities

The SUN2000 inverter exposes additional registers not yet implemented in the template. These include line-to-line voltages (A-B, B-C, C-A), fault code register, a faster-updating active power reading, total DC input energy counter, monthly and yearly energy counters, battery state of charge (SOC) and charge/discharge power, active grid power (import/export from power meter), grid exported and accumulated energy, and remote power on/shutdown commands. These can be added in a future template update.

Battery SOC (state of charge) is notably absent from the current template despite the Battery device existing. If you need SOC monitoring, it can be added as a custom Modbus device reading register H:37760 (UInt16, divide by 10, result in %).

Troubleshooting

No Modbus communication

Verify the Smart Dongle is plugged into the inverter’s USB port and has power (LED active)
Confirm the dongle’s IP address in the router’s DHCP lease table
Ensure TapHome Core and the Smart Dongle are on the same network/subnet
Check that no firewall is blocking port 502
If using WiFi AP mode, connect to the inverter’s SSID (SUN2000-<serial>) and use IP 192.168.200.1

PV string values read zero

Unused PV string inputs will always read 0 A / 0 V. This is normal if the inverter model has fewer MPPT inputs than the template provides (e.g., a 3KTL model may only use PV1 and PV2).

Battery device shows “Offline”

The LUNA2000 battery registers are only populated when a compatible battery is physically connected to the inverter. Without a battery, Running Status will read “Offline” and charge/discharge counters will be zero.

Inverter status stuck on “Idle”

During nighttime or low-irradiation conditions, the inverter enters idle mode. This is normal — it will transition to “On Grid” once sufficient solar irradiation is detected.

Available devices

SUN2000 TCP Module

SUN2000 TCP

Read (module)

var a1 := MODBUSR(H, 32008, Uint16);
var a2 := MODBUSR(H, 32009, Uint16);
IF(GETBIT(a1,0) = 1, ADDERROR("High String Voltage", 2001));
IF(GETBIT(a1,1) = 1, ADDERROR(${dc_arc_fault}, 2002));
IF(GETBIT(a1,2) = 1, ADDERROR("String Reversed", 2011));
IF(GETBIT(a1,3) = 1, ADDWARNING("PV String Backfeed ", 2012));
IF(GETBIT(a1,4) = 1, ADDWARNING("Abnormal String", 2013));
IF(GETBIT(a1,5) = 1, ADDERROR(${afci_fault}, 2021));
IF(GETBIT(a1,6)= 1, ADDERROR(${short_circ_L-PE}, 2021));
IF(GETBIT(a1,7) = 1, ADDERROR(${power_grid_fail}, 2032));
IF(GETBIT(a1,8) = 1, ADDERROR(${grid_undervoltage}, 2033));
IF(GETBIT(a1,9) = 1, ADDERROR(${grid_overvoltage}, 2034));
IF(GETBIT(a1,10) = 1, ADDERROR(${unbalanced_grid_V}, 2035));
IF(GETBIT(a1,11) = 1, ADDERROR(${grid_overfrequency}, 2036));
IF(GETBIT(a1,12) = 1, ADDERROR(${grid_underfrequency}, 2037));
IF(GETBIT(a1,13) = 1, ADDERROR(${grid_freq_instability}, 2038));
IF(GETBIT(a1,14) = 1, ADDERROR(${output_overcurr}, 2039));
IF(GETBIT(a1,15) = 1, ADDERROR(${out_DC_large}, 2040));
IF(GETBIT(a2,0) = 1, ADDERROR(${abnorm_leak_curr}, 2051));
IF(GETBIT(a2,1) = 1, ADDERROR(${abnorm_gnd}, 2061));
IF(GETBIT(a2,2) = 1, ADDERROR(${low_insul_res}, 2062));
IF(GETBIT(a2,3) = 1, ADDERROR(${high_tempt}, 2063));
IF(GETBIT(a2,4) = 1, ADDERROR(${abnorm_equip}, 2064));
IF(GETBIT(a2,5) = 1, ADDERROR(${upgrade_fail}, 2065));
IF(GETBIT(a2,6) = 1, ADDWARNING(${license_expired}, 2066));
IF(GETBIT(a2,7) = 1, ADDERROR(${abnorm_monitor_unit}, 61440));
IF(GETBIT(a2,8) = 1, ADDERROR(${power_collect_fault}, 2067));
IF(GETBIT(a2,9) = 1, ADDERROR(${abnorm_energy_storage_dev}, 2068));
IF(GETBIT(a2,10) = 1, ADDERROR("Active islanding", 2070));
IF(GETBIT(a2,11) = 1, ADDERROR("Passive islanding", 2071));
IF(GETBIT(a2,12) = 1, ADDERROR(${trans_AC_overvoltage}, 2072));
IF(GETBIT(a2,15) = 1, ADDERROR(${abnorm_PV_module_config}, 2080));

Active Power Electricity Meter

Electricity meter with active power, reactive power, power factor, and peak power of day

DC Input Power Variable Read-only

Total DC power from all PV strings combined (kW) with grid-side measurements — phase voltages, currents, and frequency

Service Attributes

Frequency

A Voltage

B Voltage

C Voltage

A Current

B Current

C Current

DC Input Power

Read

MODBUSR(H, 32064, Int32, 2)/1000

Service Attributes

Frequency

MODBUSR(H, 32085, Uint16)/100 + " Hz"

A Voltage

MODBUSR(H, 32069, Int16)/10 + " V"

B Voltage

MODBUSR(H, 32070, Int16)/10 + " V"

C Voltage

MODBUSR(H, 32071, Int16)/10 + " V"

A Current

MODBUSR(H, 32072, Int32, 2)/1000 + " A"

B Current

MODBUSR(H, 32074, Int32, 2)/1000 + " A"

C Current

MODBUSR(H, 32076, Int32, 2)/1000 + " A"

Battery Dimmer Read-only

Battery storage status and daily charge/discharge energy counters

Service Attributes

Running Status

Current Day Charge

Current Day Discharge

Battery

Read level

MODBUSR(H, 37760, Uint16)/1000

Service Attributes

Running Status

SWITCH(MODBUSR(H, 37762, Uint16),
0, "Offline", 
1, "Standby",
2, "Running",
3, "Fault",
4, "Sleep mode",
"Error"
);

Current Day Charge

MODBUSR(H, 37784, Uint32)/100 + " kWh";

Current Day Discharge

MODBUSR(H, 37786, Uint32)/100 + " kWh";

Total Energy Variable Read-only

Cumulative total energy generated since commissioning

Daily Energy Variable Read-only

PV1 Current Variable Read-only

Service Attributes

PV1 Voltage

PV2 Current Variable Read-only

Service Attributes

PV2 Voltage

PV3 Current Variable Read-only

Service Attributes

PV3 Voltage

PV4 Current Variable Read-only

Service Attributes

PV4 Voltage

Inverter Status Multi-value Switch Read-only

Inverter operating state — Idle, Starting, On-Grid, Shutdown, Grid Dispatch, IV Scanning, Spot-Check, Inspecting, DC Input Detection

Values / States: ${inverter_state} · ${idle} · ${starting} · On Grid · Shutdown · Grid Dispatch · IV scanning · Spot-Check · ${inspecting} · ${dc_input_det }

Inverter Status

Read switch state

var reg := MODBUSR(H, 32089, Uint16);
IF(reg = 0, 0,
IF(reg < 4 OR reg = 40960,1,
IF(reg = 256, 2, 
IF(reg < 515, 3, 
IF(reg < 775, 4,
IF(reg = 1025 OR reg = 1026, 5, 
IF(reg = 1280 OR reg = 1281, 7,
IF(reg = 1536, 8, 
IF(reg = 2048, 6,
IF(reg = 2304, 9
))))))))))

Service Attributes

Full State

var state := MODBUSR(H, 32089, Uint16);
SWITCH(state, 0, "Idle: Initializing",
 1,"Idle: Detecting ISO", 
 2,"Idle: Detecting irradiation", 
 3, "Idle: Grid Detecting", 
 256, "Starting", 
 512, "On-Grid", 
 513, "On-Grid: Power Limit", 
 514, "On-Grid: self-derating", 
 768, "Shutdown: Fault", 
 769, "Shutdown: Command", 
 770, "Shutdown: OVGR", 
 771,"Shutdown: Communication disconnected", 
 772, "Shutdown: Power Limit", 
 773, "Shutdown: Start manually", 
 774, "Shutdown: DC Switch OFF",
 1025, "Grid dispatch:cos(Phi)-P curve",
 1026, "Grid dispatch:Q-U curve",
40960, "Idle: No irradiation",
1280, "Spot-check",
1281, "Spot-checking",
1536, "Inspecting",
1792, "SFCI self-check",
2048, "IV scanning",
2304, "DC input detection",
"Unknown"
 );

Grid Connection

var reg := MODBUSR(H, 32000,Uint16);
IF(GETBIT(reg,0) = 1, "Standby",
IF(GETBIT(reg,2) = 1 , "Normal Grid Connection",
IF(GETBIT(reg,3) = 1, "Grid connection with derating due to power rationing",
IF(GETBIT(reg,4) = 1, "Grid connection with derating due to inverter internal causes", "Not Connected"
)
)
)
)

Teleindication

var reg := MODBUSR(H, 32000,Uint16);
IF(GETBIT(reg,0) = 1, "Standby",
IF(GETBIT(reg,5) = 1 , "Normal Stop",
IF(GETBIT(reg,6) = 1, "Stop due to faults",
IF(GETBIT(reg,7) = 1, "Stop due to power rationing",
IF(GETBIT(reg,8) = 1, "Shutdown",
IF(GETBIT(reg,9) = 1, "Spot check",
IF(GETBIT(reg,1) = 1, "Grid Connected",
"Unknown State")
)
)
)
)
)
)

Locking Status

IF(GETBIT(MODBUSR(H, 32002, Uint16),0) = 1, "Unlocked", "Locked");

PV Connection Status

IF(GETBIT(MODBUSR(H, 32002, Uint16),0) = 1, "Connected", "Disconnected");

Startup time

var reg := MODBUSR(H, 32091, Uint32, 2);
var min := FLOOR(MOD(reg, 3600)/60);
var ho := FLOOR(MOD(reg,86400)/3600);
var minutes := IF(min<10, "0" + min, min);
var hours := IF(ho<10, "0" + ho, ho);
hours + ":" + minutes;

Shutdown time

var reg := MODBUSR(H, 32093, Uint32, 2);
var min := FLOOR(MOD(reg, 3600)/60);
var ho := FLOOR(MOD(reg,86400)/3600);
var minutes := IF(min<10, "0" + min, min);
var hours := IF(ho<10, "0" + ho, ho);
hours + ":" + FLOOR(minutes);

Connection: Modbus TCP • Slave ID: $[SlaveId]

Possible improvements (17)

H:30035 Firmware Version — STR, 15 regs, read-only — useful for diagnostics
H:32010 Alarm 3 — Bitfield16, additional alarm bits not decoded in template readscript
H:32066 Line Voltage A-B — U16, V, /10, grid line-to-line voltage
H:32067 Line Voltage B-C — U16, V, /10, grid line-to-line voltage
H:32068 Line Voltage C-A — U16, V, /10, grid line-to-line voltage
H:32090 Fault Code — U16, specific fault code when device is in fault state
H:32095 Active Power (fast) — I32, kW, /1000, faster-updating active power reading
H:32108 Total DC Input Energy — U32, kWh, /100, cumulative DC energy input
H:32116 Monthly Energy — U32, kWh, /100, electricity generated this month
H:32118 Yearly Energy — U32, kWh, /100, electricity generated this year
H:37760 Battery SOC — U16, %, /10, battery state of charge — notably absent from template despite Battery device existing
H:37765 Battery Charge/Discharge Power — I32, W, positive=charging negative=discharging
H:37113 Active Grid Power — I32, W, power meter active power (grid import/export)
H:37119 Grid Exported Energy — I32, kWh, /100, energy exported to grid
H:37123 Grid Accumulated Energy — U32, kWh, /100, total energy from grid
H:40200 Power On — WO, E16, remote inverter power-on command
H:40201 Shutdown — WO, E16, remote inverter shutdown command

Download Template

Sources

Solar Inverter Modbus Interface Definitions (V3.0)
community.symcon.de 2026-03-13
PDF
huawei-solar-lib — Python Modbus Library
github.com 2026-03-13