All three phase power registers return zero. What is wrong?

The most common cause is that the RS485 slave ID on the inverter is still at its factory default of 000. Navigate to Settings > Communication > RS485 > Device ID on the inverter panel and set it to 247. Also check that the A and B wires are not swapped: a constantly flashing RX LED on the RS485 adapter with no TX response is a reliable sign of reversed polarity.

The Gateway connects but phase readings seem inverted or wrong sign.

Registers 31026 to 31028 are signed int16 values where positive indicates export to the grid and negative indicates import from the grid. If your readings are consistently opposite to what you expect, confirm that the smart meter or CT clamp connected to the inverter is wired in the correct direction according to the FoxESS installation manual.

Can I connect the ModbusCloud Gateway via the inverter's Ethernet port?

No. The FoxESS H3 Series does not expose Modbus on its Ethernet port. TCP port 502 is not open on the H3's LAN interface. Modbus RTU over RS485 is the only supported path. Use an RS485 to USB or RS485 to serial adapter connected to the inverter's CT/COM connector.

The energy register at 32012 shows an unexpectedly large value. Is this correct?

Register 32012 is a uint32 cumulative counter and holds the total lifetime grid energy, not a daily or session value. The raw register value may require a scaling factor applied by your integration layer to convert it to the correct engineering unit. Cross-check against the FoxESS app or display to confirm the absolute reading matches.

Free Modbus template: FoxESS H3 Series Hybrid Inverter (grid)

The FoxESS H3 Series Hybrid Inverter is a three-phase hybrid solar inverter designed for residential and light-commercial PV-plus-battery installations. It converts PV power to AC, charges a connected battery, and can feed surplus energy into the grid. This ModbusCloud template reads the H3 Series grid-side registers over Modbus RTU via RS485: per-phase active power on phases R, S, and T (registers 31026 to 31028, signed watts, positive export, negative import) and a cumulative energy counter at register 32012. Connecting these four registers to the ModbusCloud portal gives installers continuous visibility of grid exchange on every phase without relying on the FoxESS cloud.

Name	Address	Function	Type	Unit	Access
power_a Grid meter active power on phase R (L1), positive = export, negative = import.	31026	FC03	int16	W	R
power_b Grid meter active power on phase S (L2), positive = export, negative = import.	31027	FC03	int16	W	R
power_c Grid meter active power on phase T (L3), positive = export, negative = import.	31028	FC03	int16	W	R
energy Cumulative grid energy counter, 32-bit unsigned integer.	32012	FC03	uint32		R