The gateway connects but register reads time out. Why?

The SUN2000 Modbus TCP interface requires a longer response time than most devices. Set the Modbus request timeout in the ModbusCloud Gateway configuration to at least 800 ms. Timeouts below 500 ms will produce frequent read errors even when the connection is otherwise healthy.

Which TCP port should I use for the SUN2000?

Older SUN2000 firmware uses port 502. Newer firmware versions use port 6607. Check the inverter's communication settings or Smart Dongle interface to confirm the active port, and update the device configuration in your ModbusCloud portal accordingly.

Power reads zero even though the inverter is producing energy.

Modbus TCP must be explicitly enabled in the inverter's internal menu, not just in the Smart Dongle. If TCP was enabled only at the dongle level, the inverter may reject register requests. Re-enable Modbus TCP from the inverter's own settings menu and retry. Also confirm the unit ID matches (default is 1).

Energy register 32106 shows an unexpectedly small value. Is it scaled?

Yes. Register 32106 returns a raw uint32 value with a gain of 100, meaning the actual energy in kWh is the raw value divided by 100. ModbusCloud applies this scaling automatically via the template, but if you are also reading the register externally, apply the same factor to avoid misreading the total yield.

Free Modbus template: Huawei SUN2000 Inverter (without battery) (pv)

The Huawei SUN2000 is a string PV inverter for residential and light-commercial solar installations. This ModbusCloud template connects over Modbus TCP and reads two key registers: active AC output power (address 32080) and cumulative energy yield (address 32106). Together these give you a live view of generation and a running lifetime production total. Import the template in one click and start tracking your SUN2000 site in the ModbusCloud portal without manual register configuration.

Name	Address	Function	Type	Unit	Access
power Active AC output power of the inverter, in watts.	•••	•••	•••	W	R
energy Cumulative AC energy yield since commissioning, in watt-hours.	•••	•••	•••	Wh	R

Huawei SUN2000 Inverter (without battery) (pv)

Overview

Use cases

Installation

Things to watch for

Registers (2)

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