GoodWe StsBox
The GoodWe StsBox is a Static Transfer Switch designed for commercial and industrial energy storage systems, managing automatic switching between grid, battery inverter, and generator sources. This Modbus TCP template reads device identity (serial number, firmware version and sub-version), generator voltage and frequency acceptance limits, contactor voltage thresholds, delay-before-load, start mode, charge limit, and rated power. Matching write registers allow remote reconfiguration of all genset parameters from your ModbusCloud portal. The template gives installers a single monitoring and configuration point for GoodWe StsBox generator integration without on-site access.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 29, read and write
- Brand
- GoodWe
- Last updated
Registers (29)
16 read, 13 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| serial_number | Read | ||||
| version | Read | ||||
| sub_version | Read | ||||
| port_mutliplexing_mode_a | Read | ||||
| genset_upper_voltage_limit_a | V | Read | |||
| genset_lower_voltage_limit_a | V | Read | |||
| genset_upper_frequency_limit_a | Hz | Read | |||
| genset_lower_frequency_limit_a | Hz | Read | |||
| delay_before_load_a | s | Read | |||
| genset_start_mode_selection_a | Read | ||||
| one_click_enable_a | Read | ||||
| genset_charge_limit_a | W | Read | |||
| open_voltage_a | V | Read | |||
| closed_voltage_a | V | Read | |||
| genset_run_time_a | s | Read | |||
| genset_rated_power_a | W | Read | |||
| port_mutliplexing_mode_b | Write | ||||
| genset_upper_voltage_limit_b | V | Write | |||
| genset_lower_voltage_limit_b | V | Write | |||
| genset_upper_frequency_limit_b | Hz | Write | |||
| genset_lower_frequency_limit_b | Hz | Write | |||
| delay_before_load_b | s | Write | |||
| genset_start_mode_selection_b | Write | ||||
| one_click_enable_b | Write | ||||
| genset_charge_limit_b | W | Write | |||
| open_voltage_b | V | Write | |||
| closed_voltage_b | V | Write | |||
| genset_run_time_b | s | Write | |||
| genset_rated_power_b | W | Write |
Loading registers…
Send your device list
If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor firmware version and sub-version to verify the StsBox is running a supported software release before commissioning.
- Track genset_upper_voltage_limit and genset_lower_voltage_limit to confirm generator acceptance window matches local grid standards.
- Alert on genset_start_mode_selection changing unexpectedly to detect unauthorised or accidental mode switches on site.
- Verify delay_before_load values remotely to ensure load transfer timing complies with site protection coordination settings.
- Compare genset_rated_power against actual generator capacity to flag mismatches that could trip overload protection during backup events.
Installation
Enable Modbus TCP communication on the GoodWe StsBox by accessing the inverter or StsBox web interface and activating the Modbus TCP service under the communication or Modbus section; note the assigned IP address and unit ID (default 247 for GoodWe devices).
Connect the StsBox to the same local network as the ModbusCloud Gateway using an Ethernet cable, ensuring both devices share a routable subnet and that TCP port 502 is not blocked by a firewall.
In the ModbusCloud portal, add a new Gateway, import the GoodWe StsBox template, and assign the correct unit ID and IP address that match the StsBox network configuration.
Verify the connection by spot-checking the serial_number register (address 33288) in the portal: a non-empty string response confirms Modbus TCP communication is active and the register map is aligned.
Things to watch for
Why do all register reads return zero or timeout?
The GoodWe StsBox requires Modbus TCP to be explicitly enabled via the device interface or the paired inverter's LAN module. Confirm the LAN module is installed, Modbus TCP is active, and that the ARM firmware meets the minimum version requirement. Also verify that port 502 is reachable from the ModbusCloud Gateway.
The serial_number register returns garbled characters. What is wrong?
The serial_number is stored as a multi-register string using big-endian byte order. Ensure your Modbus client is set to big-endian word and byte order. Reading fewer consecutive registers than the full string length will produce truncated or misaligned output.
Write registers are not accepted and the device returns an exception code.
GoodWe devices may reject FC16 writes if the unit ID is incorrect or if the LAN module firmware does not support write operations. Confirm the unit ID matches (default 247), check firmware version, and ensure no other Modbus master is holding a concurrent session, as GoodWe TCP allows only one active connection at a time.
Is it safe to write genset voltage limits or start mode remotely?
Use caution with all write registers on the GoodWe StsBox. Writing incorrect genset_upper_voltage_limit, genset_lower_voltage_limit, genset_upper_frequency_limit, or genset_start_mode_selection values can cause the StsBox to reject valid generator output, prevent automatic backup switching, or trigger protective shutdowns. Always verify values against the site's generator specifications before writing, and test changes during a scheduled maintenance window.
Want to see how it works?
