Why do the current and power registers show values roughly two or three times too high?

The my-PV WiFi Meter does not automatically correct readings when non-standard CT sizes are used. If you installed 200A or 400A clamp-on transducers instead of the default 75A units, you must manually apply the CT correction factor. For 200A CTs, multiply raw values by 200/75 = 2.6667. Check the CT size installed and apply the corresponding factor.

The Gateway connects but all register values read zero or show errors. What should I check?

Confirm the meter's WIFI LED is lit red, indicating an active WLAN connection. Verify the Gateway is on the same subnet as the meter. Check that device ID 1 and port 502 are set in the portal. If the meter recently lost Wi-Fi (e.g. after a router restart), power-cycle the meter to restore connectivity.

Phase A shows power but phases B and C read zero. Is the template misconfigured?

This almost always means one or two clamp-on CTs are not correctly seated around their phase conductor, or are connected to the wrong CT terminal on the meter. Re-check that each transducer is clamped firmly around a single phase wire and wired to its corresponding terminal (UA, UB, UC) on the meter body.

The power register alternates between positive and negative unexpectedly. Is this normal?

The total power register (address 32) is a signed int32, where positive values indicate grid import and negative values indicate export. Rapid sign changes simply reflect the PV system transitioning between import and export. If the transitions seem implausible, check that the CT clamps are oriented in the same direction on all three phases, as a reversed CT will invert the sign.

Free Modbus template: my-PV WiFi Meter (grid)

The my-PV WiFi Meter is a three-phase grid-connection meter designed for PV self-consumption monitoring in residential and light-commercial installations. Mounted in the distribution cabinet after the utility meter, it uses clamp-on current transducers to measure grid power flow without interrupting the phases. Over Modbus TCP (port 502, device ID 1), the template reads total active power and cumulative energy at the grid point, plus per-phase currents and active power for phases A, B, and C. This gives installers and building owners precise, phase-resolved visibility into import and export flows directly in the ModbusCloud portal.

Name	Address	Function	Type	Unit	Access
power Total three-phase active power at the grid connection point, signed in watts.	32	FC03	int32	W	R
energy Cumulative active energy measured at the grid connection point.	34	FC03	uint32	Wh	R
currents_a RMS current on phase A, measured via clamp-on CT.	1	FC03	uint16	A	R
currents_b RMS current on phase B, measured via clamp-on CT.	11	FC03	uint16	A	R
currents_c RMS current on phase C, measured via clamp-on CT.	21	FC03	uint16	A	R
powers_a Active power on phase A, signed, in watts.	2	FC03	int32	W	R
powers_b Active power on phase B, signed, in watts.	12	FC03	int32	W	R
powers_c Active power on phase C, signed, in watts.	22	FC03	int32	W	R

my-PV WiFi Meter (grid)

Overview

Use cases

Installation

Things to watch for

Registers (8)

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