VM-3P75CT meter: GX does not see it or the readings are wrong

The meter has no separate power supply — it draws power from the L1 and N terminals (85–265 V AC, 1.45 W consumption). Check the voltage between L1 and N at the meter terminals and the switch that supplies it.

Protection according to the manual: if the meter is connected with cable of the same cross-section as the rest of the circuit after the main breaker, no additional breaker is needed (in most installations in Europe this is 2.5 mm² with a 16 A breaker). With a different cross-section, you need to install a separate breaker in accordance with regulations. The voltage terminals accept 1.0–2.5 mm² conductors.

• Via VE.Can — the meter is detected automatically when connected to the VE.Can port and the bus is correctly terminated. The VE.Can network must have terminators at both ends (two are included), and the GX device’s VE.Can port must be set to the 250 kbit/s profile.
• Via Ethernet — connect the meter to the same local network (router) as the GX device (via Ethernet or Wi-Fi). GX recognises it automatically, but you still need to enable it: Settings → Integrations → Modbus Devices → Discovered devices. After first installation and enabling, it is disabled. It is best to leave the IP address on “Automatic (DHCP)”; manual setup is needed very rarely.
• Cables — in both cases, use a good RJ45 network cable, for example Victron RJ45 UTP.
• The Multi RS Solar and Inverter RS Smart manuals recommend avoiding intermediate Wi-Fi links between the meter and GX — they can introduce delays and reduce reliability.

In an ESS system, a missing grid meter causes error #49, and the system may switch to passthrough mode — see “ESS is drawing power from the grid”. Other causes of invisible devices: “GX cannot see the device”.

In VictronConnect (the gear icon on the Status or Energy page):

• Roles — Grid meter (default), PV inverter, Generator, AC load, EV charger or Heat pump, depending on what you are measuring.
• Position — for the PV inverter, AC load, EV charger and Heat pump roles: whether the meter is on the AC input side or the AC output side of the inverter/charger.
• Phase configuration — “Only L1” for a single-phase installation, “3-phase” (default) for three-phase, “Split phase” for split-phase.

Once the role is set, configuration is complete. You can connect to the meter directly via Ethernet (Modbus/UDP on the local network) or remotely through VictronConnect-Remote when the GX device is connected to VRM.

• Direction — the transformer has an arrow marked L ← K. It must point towards the loads.
• Correct input and phase — each transformer is marked with the input it belongs to and must clamp around the conductor of the correct phase. The transformers are factory-calibrated together with the inputs — swapping them reduces accuracy.
• Voltage terminals — check that the correct wires have been connected to N, L1, L2 and L3.
• Phase sequence — the Status page in VictronConnect shows the phase sequence in a three-phase configuration; you can enable the wrong-sequence warning with the “Phase rotation” setting (disabled by default).
• Extended transformer leads — they can be extended, but the measurement noise increases slightly. Twist the cores as in the factory cables.
• Installation — the transformers are delicate: open the part marked A in the manual, taking care not to twist the head, and close the head by hand. You can order a damaged transformer from a Victron dealer; it should be replaced by a qualified person.

The meter shows the active power of each phase: P = U × I × cos φ (in a three-phase system with the √3 factor). With inductive and capacitive loads the power factor drops, and apparent power (U × I) is greater than active power — this is normal. Check the power factor shown by the meter: a low value confirms that the cause is reactive loads.

• Small electronic devices, such as USB chargers and LED lighting, have a particularly low power factor.
• Generating equipment, such as PV inverters, must by law operate with a power factor close to 1 — this can increase the difference because the loads then account for the ‘weak’ power factor.
• Solutions from the manual: loads with built-in power factor correction (common in modern computer power supplies) or separate power factor compensation devices.

Energy different from the meter reading on the utility meter? Check the “Energy registration method” setting (factory default Vector; arithmetic and absolute are also available). The methods vary by country — confirm it with your energy supplier.

This is bootloader mode. Either a firmware update is in progress — after it finishes, the meter returns to normal operation by itself (the LED lights green) — or the update failed and the meter is waiting for another attempt. Repeat the update.

• In bootloader mode, you can update the meter only locally with VictronConnect (Ethernet or Wi-Fi on the local network) or remotely from VRM (Remote firmware update, via VE.Can or Ethernet). You cannot do it via VictronConnect-Remote.
• If the update via Ethernet fails, connect the meter to GX via VE.Can, update it, and then switch back to Ethernet.

More about updates: “Firmware update failed”.

These codes have a different meaning in the meter — code 122 on Orion XS chargers means something else.

• Restart without disconnecting the power — briefly press the recessed RESET button. The LED goes off and immediately comes on again.
• Reset with the button — press and hold RESET: the LED goes off for about 3 seconds, the meter starts up and the LED lights green again. Keep holding for about 10 seconds more, until the LED goes off again, then release — the meter will start up.
• Reset in VictronConnect — device list → cogwheel → three dots → “Reset to defaults” → “YES”.

Reset restores: automatic IP address (DHCP), Grid role, three-phase configuration and the “VM-3P75CT” name with the serial number. Then you need to configure the meter again (step 3).