All six string power registers return zero even in full sun. Why?

Confirm the RS485 wires are connected to the correct EMS 485 A/B pins on the inverter's COM connector, not to the Meter 485 pins. Also verify the unit ID matches the inverter setting (factory default is 247) and that the baud rate in the Gateway matches the inverter's RS485 configuration.

I get exception code 0x83 or a timeout. What is wrong?

Exception 0x83 (illegal data address) or timeouts on the H3-Pro/Smart often occur when reads span a range that the inverter restricts to individual register reads. Reduce the batch read size in your Gateway settings to 50 registers or fewer per request, as this is a known requirement for the H3-Pro model.

String power values seem correct but are always slightly offset. How do I fix this?

The official FoxESS protocol documents these registers as int32 (two consecutive 16-bit registers). If you see values that are always a fraction of the expected output, verify the data type is set to int32 and not int16. Reading only the high or low word of a 32-bit pair produces a scaled-down or zero result.

The H3-Pro/Smart uses a different register map than the standard H3. Which template do I need?

The H3-Pro and H3-Smart use a distinct register layout that differs from the standard H3 series. Always use this dedicated H3-Pro/Smart template rather than a generic H3 template. Applying the wrong template will result in mismatched addresses and incorrect or absent readings across all six string registers.

Free Modbus template: FoxESS H3-Pro/Smart Series Hybrid Inverter (pv)

The FoxESS H3-Pro/Smart Series is a three-phase hybrid inverter for residential and commercial solar-plus-storage installations. This Modbus RTU template reads per-string PV power across six input strings (power_a through power_f, addresses 39279 to 39289), giving you a live view of each MPPT channel's contribution. With per-string resolution in your ModbusCloud portal, you can detect underperforming strings, shading effects, and soiling losses as they happen rather than waiting for end-of-day yield reports.

Name	Address	Function	Type	Access
power_a Instantaneous DC power output of PV string 1, in watts.	39279	FC03	int32	R
power_b Instantaneous DC power output of PV string 2, in watts.	39281	FC03	int32	R
power_c Instantaneous DC power output of PV string 3, in watts.	39283	FC03	int32	R
power_d Instantaneous DC power output of PV string 4, in watts.	39285	FC03	int32	R
power_e Instantaneous DC power output of PV string 5, in watts.	39287	FC03	int32	R
power_f Instantaneous DC power output of PV string 6, in watts.	39289	FC03	int32	R