ModbusTCP connection drops immediately after successful initial read

[RnoTheKing]

Description of the Issue

During the configuration of the Huawei Solar integration via Modbus TCP, the connection repeatedly fails.

The integration successfully performs the initial Modbus transactions (confirmed by the logs showing the model name, though not present in the final log block below), but the connection is then immediately dropped or times out, causing the configuration to fail. The error is characterized by an asyncio.exceptions.CancelledError leading to a Request cancelled outside pymodbus message.

Environment

• Home Assistant Core Version: 2025.10.2
• Huawei Solar Integration Version: Latest (via HACS)
• Connection Target (Host): [IP address of SDongle]
• Modbus Port: 502
• Slave ID(s): 1 OR AUTO
• Connection Device: SDongle A-05 (wifi)

Device Software Versions:

• Data Logger (SDongleA-05): V200R025C00SPC110
• Inverter (SUN2000-4KTL-M1): V100R001C00SPC173
• Battery (LUNA2000-1): V100R002C00SPC637

Error Message / Traceback

This error originated from a custom integration.

Logger: pymodbus.logging
Source: custom_components/huawei_solar/config_flow.py:205
integration: Huawei Solar (documentation, issues)
First occurred: 1:11:56 PM (11 occurrences)
Last logged: 1:32:48 PM

Repeating.... >>>>> send: 0x0 0x1 0x0 0x0 0x0 0x6 0x0 0x3 0x75 0x30 0x0 0xf
Repeating....
No response received after 3 retries, continue with next request
Cancel send, because not connected! >>>>> send: 0x0 0x1 0x0 0x0 0x0 0x6 0x1 0x3 0x75 0x30 0x0 0xf
Cancel send, because not connected!

This error originated from a custom integration.

Logger: custom_components.huawei_solar.config_flow
Source: custom_components/huawei_solar/config_flow.py:537
integration: Huawei Solar (documentation, issues)
First occurred: 1:12:44 PM (2 occurrences)
Last logged: 1:32:51 PM

Unexpected exception while connecting via ModbusTCP
Traceback (most recent call last):
  File "/usr/local/lib/python3.13/site-packages/pymodbus/transaction/transaction.py", line 175, in execute
    response = await asyncio.wait_for(
    ...
    )
    ^
  File "/usr/local/lib/python3.13/asyncio/tasks.py", line 507, in wait_for
    return await fut
    ...
asyncio.exceptions.CancelledError

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/config/custom_components/huawei_solar/config_flow.py", line 537, in async_step_setup_network
    info = await validate_network_setup(
    ...
    )
    ^
  File "/config/custom_components/huawei_solar/config_flow.py", line 205, in validate_network_setup
    bridge = await create_tcp_bridge(
    ...
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 693, in create_tcp_bridge
    return await _create(await AsyncHuaweiSolar.create(host, port, slave_id), slave_id)
    ...
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 731, in _create
    return await candidate_bridge_class.create(
    ...
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 97, in create
    await bridge._populate_additional_fields()
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 421, in _populate_additional_fields
    self.has_optimizers = (await self.client.get(rn.NB_OPTIMIZERS, self.slave_id)).value
    ...
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 261, in get
    return (await self.get_multiple([name], slave_id))[0]
    ...
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 305, in get_multiple
    response = await self._read_registers(
    ...
    )
    ^
  File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 442, in _

[joevoo82]

Have you found a solution to your connection problems yet?

I have a similar configuration with the same software and firmware versions:

Environment

Home Assistant Core Version: 2025.10.4
Huawei Solar Integration Version: Latest (via HACS)
Connection Target (Host): [IP address of SDongle]
Modbus Port: 502
Slave ID(s): 1 and 2
Connection Device: SDongle A-05 (wifi)
Device Software Versions:

Data Logger (SDongleA-05): V200R025C00SPC110
Inverter (SUN2000-8KTL-M1: V100R001C00SPC173
Inverter (SUN2000-4.6KTL-L1): V200R001C00SPC151
Battery (LUNA2000-1): V100R002C00SPC637
MBUS: V100R001C00SPC344

The SUN2000-8KTL-M1 is my master, which I tried to reconnect first. This did not work right away, only after I completely restarted Home Assistant.
The connection remained persistent until I tried to add the slave (SUN2000-4.6KTL-L1). From that point on, all entities reverted to “Unknown” status.
Only after restarting the HA instance and deactivating/deleting the slave was it possible to extract data from the master again.

2025-10-24 12:12:14.398 DEBUG (MainThread) [huawei_solar.bridge] Batch update of the following registers: power_meter_active_power, active_grid_power_factor, active_grid_frequency, grid_exported_energy, grid_accumulated_energy, active_grid_A_power, active_grid_B_power, active_grid_C_power 2025-10-24 12:12:14.399 DEBUG (MainThread) [huawei_solar.huawei_solar] Sleeping for 0.046077 seconds before making next call 2025-10-24 12:12:14.446 DEBUG (MainThread) [huawei_solar.huawei_solar] Reading register 37113 with length 25 from server 1 2025-10-24 12:12:14.446 DEBUG (MainThread) [pymodbus.logging] send: 0x0 0x1 0x0 0x0 0x0 0x6 0x1 0x3 0x90 0xf9 0x0 0x19 2025-10-24 12:12:14.453 DEBUG (MainThread) [pymodbus.logging] recv: 0x0 0x1 0x0 0x0 0x0 0x35 0x1 0x3 0x32 0x0 0x0 0x1 0x24 0x0 0x0 0x3 0x15 0xff 0x27 0x13 0x8c 0x0 0x8 0x32 0x6b 0x0 0x16 0xab 0x45 0x0 0x0 0x0 0x0 0x0 0x1 0x0 0x0 0xf 0xd3 0x0 0x0 0xf 0xd8 0x0 0x0 0xf 0xd5 0xff 0xff 0xff 0xbd 0x0 0x0 0x0 0x54 0x0 0x0 0x1 0x13 extra data: 2025-10-24 12:12:14.453 DEBUG (MainThread) [pymodbus.logging] Processing: 0x0 0x1 0x0 0x0 0x0 0x35 0x1 0x3 0x32 0x0 0x0 0x1 0x24 0x0 0x0 0x3 0x15 0xff 0x27 0x13 0x8c 0x0 0x8 0x32 0x6b 0x0 0x16 0xab 0x45 0x0 0x0 0x0 0x0 0x0 0x1 0x0 0x0 0xf 0xd3 0x0 0x0 0xf 0xd8 0x0 0x0 0xf 0xd5 0xff 0xff 0xff 0xbd 0x0 0x0 0x0 0x54 0x0 0x0 0x1 0x13 2025-10-24 12:12:14.453 DEBUG (MainThread) [pymodbus.logging] decoded PDU function_code(3 sub -1) -> ReadHoldingRegistersResponse(dev_id=0, transaction_id=0, address=0, count=0, bits=[], registers=[0, 292, 0, 789, 65319, 5004, 8, 12907, 22, 43845, 0, 0, 1, 0, 4051, 0, 4056, 0, 4053, 65535, 65469, 0, 84, 0, 275], status=1, retries=0) 2025-10-24 12:12:14.604 DEBUG (MainThread) [pymodbus.logging] Connecting comm 2025-10-24 12:12:14.605 DEBUG (MainThread) [pymodbus.logging] Connected to comm 2025-10-24 12:12:14.605 DEBUG (MainThread) [huawei_solar.modbus] Waiting for 1500 milliseconds after connection before performing operations 2025-10-24 12:12:14.607 DEBUG (MainThread) [pymodbus.logging] -> transport: received eof 2025-10-24 12:12:14.607 DEBUG (MainThread) [pymodbus.logging] Connection lost comm due to None 2025-10-24 12:12:14.607 DEBUG (MainThread) [pymodbus.logging] Wait comm 1000 ms before reconnecting. 2025-10-24 12:12:14.978 DEBUG (MainThread) [pymodbus.logging] recv: 0x0 0x1 0x0 0x0 0x0 0x21 0x1 0x3 0x1e 0x2 0x94 0x0 0x0 0x0 0x7 0x0 0x0 0x13 0x88 0x0 0x0 0x13 0x88 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x3 0x20 0x0 0x0 0x0 0x72 extra data: 2025-10-24 12:12:14.978 DEBUG (MainThread) [pymodbus.logging] Processing: 0x0 0x1 0x0 0x0 0x0 0x21 0x1 0x3 0x1e 0x2 0x94 0x0 0x0 0x0 0x7 0x0 0x0 0x13 0x88 0x0 0x0 0x13 0x88 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x0 0x3 0x20 0x0 0x0 0x0 0x72 2025-10-24 12:12:14.978 ERROR (MainThread) [pymodbus.logging] ERROR: request ask for id=2 but got id=1, Skipping. 2025-10-24 12:12:15.608 DEBUG (MainThread) [pymodbus.logging] Connecting comm 2025-10-24 12:12:15.609 DEBUG (MainThread) [pymodbus.logging] Connected to comm 2025-10-24 12:12:15.609 DEBUG (MainThread) [huawei_solar.modbus] Waiting for 1500 milliseconds after connection before performing operations 2025-10-24 12:12:15.612 DEBUG (MainThread) [pymodbus.logging] -> transport: received eof 2025-10-24 12:12:15.612 DEBUG (MainThread) [pymodbus.logging] Connection lost comm due to None 2025-10-24 12:12:15.614 DEBUG (MainThread) [pymodbus.logging] Wait comm 1000 ms before reconnecting. 2025-10-24 12:12:16.614 DEBUG (MainThread) [pymodbus.logging] Connecting comm 2025-10-24 12:12:16.615 DEBUG (MainThread) [pymodbus.logging] Connected to comm 2025-10-24 12:12:16.615 DEBUG (MainThread) [huawei_solar.modbus] Waiting for 1500 milliseconds after connection before performing operations 2025-10-24 12:12:16.617 DEBUG (MainThread) [pymodbus.logging] -> transport: received eof 2025-10-24 12:12:16.617 DEBUG (MainThread) [pymodbus.logging] Connection lost comm due to None 2025-10-24 12:12:16.618 DEBUG (MainThread) [pymodbus.logging] Wait comm 1000 ms before reconnecting. 2025-10-24 12:12:17.618 DEBUG (MainThread) [pymodbus.logging] Connecting comm 2025-10-24 12:12:17.619 DEBUG (MainThread) [pymodbus.logging] Connected to comm 2025-10-24 12:12:17.619 DEBUG (MainThread) [huawei_solar.modbus] Waiting for 1500 milliseconds after connection before performing operations 2025-10-24 12:12:17.622 DEBUG (MainThread) [pymodbus.logging] -> transport: received eof 2025-10-24 12:12:17.622 DEBUG (MainThread) [pymodbus.logging] Connection lost comm due to None 2025-10-24 12:12:17.623 DEBUG (MainThread) [pymodbus.logging] Wait comm 1000 ms before reconnecting. 2025-10-24 12:12:18.623 DEBUG (MainThread) [pymodbus.logging] Connecting comm 2025-10-24 12:12:18.624 DEBUG (MainThread) [pymodbus.logging] Connected to comm 2025-10-24 12:12:18.624 DEBUG (MainThread) [huawei_solar.modbus] Waiting for 1500 milliseconds after connection before performing operations 2025-10-24 12:12:18.627 DEBUG (MainThread) [pymodbus.logging] -> transport: received eof 2025-10-24 12:12:18.627 DEBUG (MainThread) [pymodbus.logging] Connection lost comm due to None 2025-10-24 12:12:18.628 DEBUG (MainThread) [pymodbus.logging] Wait comm 1000 ms before reconnecting. 2025-10-24 12:12:19.629 DEBUG (MainThread) [pymodbus.logging] Connecting comm 2025-10-24 12:12:19.630 DEBUG (MainThread) [pymodbus.logging] Connected to comm 2025-10-24 12:12:19.631 DEBUG (MainThread) [huawei_solar.modbus] Waiting for 1500 milliseconds after connection before performing operations 2025-10-24 12:12:19.632 DEBUG (MainThread) [pymodbus.logging] -> transport: received eof 2025-10-24 12:12:19.632 DEBUG (MainThread) [pymodbus.logging] Connection lost comm due to None 2025-10-24 12:12:19.632 DEBUG (MainThread) [pymodbus.logging] Wait comm 1000 ms before reconnecting. 2025-10-24 12:12:20.428 ERROR (MainThread) [pymodbus.logging] No response received after 3 retries, continue with next request 2025-10-24 12:12:20.428 ERROR (MainThread) [homeassistant.config_entries] Error setting up entry SUN2000-4.6KTL-L1 for huawei_solar Traceback (most recent call last): File "/usr/src/homeassistant/homeassistant/config_entries.py", line 761, in __async_setup_with_context result = await component.async_setup_entry(hass, self) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/config/custom_components/huawei_solar/__init__.py", line 97, in async_setup_entry primary_bridge = await create_tcp_bridge( ^^^^^^^^^^^^^^^^^^^^^^^^ ...<3 lines>... ) ^ File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 693, in create_tcp_bridge return await _create(await AsyncHuaweiSolar.create(host, port, slave_id), slave_id) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 731, in _create return await candidate_bridge_class.create( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...<5 lines>... ) ^ File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 97, in create await bridge._populate_additional_fields() File "/usr/local/lib/python3.13/site-packages/huawei_solar/bridge.py", line 461, in _populate_additional_fields await self.client.get(rn.METER_STATUS, self.slave_id) File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 261, in get return (await self.get_multiple([name], slave_id))[0] ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 305, in get_multiple response = await self._read_registers( ^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...<3 lines>... ) ^ File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 442, in _read_registers return await _do_read() ^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.13/site-packages/backoff/_async.py", line 151, in retry ret = await target(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.13/site-packages/backoff/_async.py", line 151, in retry ret = await target(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/local/lib/python3.13/site-packages/huawei_solar/huawei_solar.py", line 389, in _do_read response = await self._client.read_holding_registers( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ...<3 lines>... ) ^ File "/usr/local/lib/python3.13/site-packages/pymodbus/transaction/transaction.py", line 201, in execute raise ModbusIOException(txt) pymodbus.exceptions.ModbusIOException: Modbus Error: [Input/Output] No response received after 3 retries, continue with next request

[Niclas82]

Had similar problems. solution was to enable modbus (restricted) and enter the ip to Homeassistant