A-Tronix wattsonic (pv)
The A-Tronix wattsonic is a hybrid solar inverter sold under the Wattsonic platform and distributed as the A-Tronix brand. This template reads the PV output power register (address 11028) over Modbus TCP, using function code 3 on the inverter's built-in LAN interface at port 502. Connecting the wattsonic to ModbusCloud Gateway gives installers a live, cloud-accessible view of solar generation without relying on the proprietary Wattsonic cloud app. The single power register returns a signed 32-bit watt value, making it suitable for real-time PV yield monitoring.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 1, read only
- Brand
- A-Tronix
- Compatible models
- wattsonic
- Last updated
Registers (1)
1 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| power | W | Read |
Loading registers…
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Use cases
- Monitor real-time PV output power to verify the inverter is producing expected yield after installation.
- Track daily PV power curves to detect shading events or soiling causing sustained output drops.
- Alert on PV power falling to zero during daylight hours to catch inverter faults early.
- Compare live PV power readings against irradiance forecasts to flag underperforming strings.
- Report monthly PV generation trends to building owners as part of regular performance reviews.
Installation
Confirm the wattsonic inverter has a LAN or Wi-Fi module installed and is reachable on your local network; note its IP address from your router's DHCP table.
Connect the ModbusCloud Gateway to the same LAN segment as the inverter, ensuring port 502 (Modbus TCP) is not blocked by any firewall or VLAN policy.
In the ModbusCloud portal, add a new device, import the A-Tronix wattsonic (pv) template, set the host to the inverter's IP address, port 502, and unit ID 255.
Trigger a manual poll and verify the power register (address 11028) returns a plausible watt value during daylight; a value of zero at night is expected and correct.
Things to watch for
The gateway connects but the power register always reads zero.
Zero at night is correct behaviour. During daylight, confirm the inverter is in normal operating mode and that the LAN module is active. Check that unit ID is set to 255, not the default 1, as the Wattsonic LAN interface requires unit ID 255 for TCP polling.
I receive a Modbus exception code 2 (illegal data address) on address 11028.
Some Wattsonic firmware versions use 0-based addressing internally. If your polling tool adds an offset automatically, try address 11027 instead. The OpenEMS template targets address 11028 directly over TCP, so no manual offset should be needed when using the ModbusCloud portal.
The connection times out intermittently even though the inverter is reachable.
The Wattsonic LAN module can be slow to respond. Set your Modbus TCP timeout to at least 10 seconds in the ModbusCloud Gateway configuration. Intermittent timeouts are also reported when the inverter is in standby or grid-fault recovery mode.
Can I read both PV power and battery or grid data with this template?
This template covers only the single PV power register (address 11028). Battery SOC, grid power, and other registers are not included. If you need those values, check the ModbusCloud template library for a more complete Wattsonic template that covers additional register groups.
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