Fenecon Pro PvMeter
The Fenecon Pro PvMeter is a per-phase PV production meter integrated into the Fenecon FEMS energy management platform. It connects to external monitoring via Modbus TCP through the FEMS Modbus/TCP API. This template reads three register groups: per-phase AC voltage on L1, L2, and L3; instantaneous active power per phase; and cumulative active production energy per phase. Installers use it in ModbusCloud to track PV generation imbalances, verify three-phase output, and build long-term yield histories across Fenecon Pro installations.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 9, read only
- Brand
- Fenecon
- Last updated
Registers (9)
9 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| voltage_l1 | V | Read | |||
| voltage_l2 | V | Read | |||
| voltage_l3 | V | Read | |||
| active_production_energy_l1 | Wh | Read | |||
| active_power_l1 | W | Read | |||
| active_production_energy_l2 | Wh | Read | |||
| active_power_l2 | W | Read | |||
| active_production_energy_l3 | Wh | Read | |||
| active_power_l3 | W | Read |
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If a device is not in the library yet, we build the template for free as soon as we have the register data.
Use cases
- Monitor per-phase PV active power in real time to detect string or inverter output imbalances across L1, L2, and L3.
- Track cumulative production energy per phase over time to verify annual yield against commissioning estimates.
- Alert on unexpected drops in active power on a single phase to identify potential PV string faults early.
- Compare L1, L2, and L3 voltages over time to spot persistent phase imbalances at the grid connection point.
- Report per-phase PV production data to building owners or asset managers as part of monthly performance summaries.
Installation
Enable the FEMS App Modbus/TCP Read Access on the Fenecon system by redeeming a licence key in the FEMS App Center under Settings, then confirm the app appears as installed.
Connect the ModbusCloud Gateway to the same LAN as the FEMS controller so it can reach the FEMS IP address; the default Modbus TCP port is 502.
In the ModbusCloud portal, add the Gateway, import the Fenecon Pro PvMeter template, and set the unit ID to 1 (the default FEMS Modbus slave ID) unless your system uses a custom mapping.
Spot-check the connection by reading register 121 for voltage_l1 and register 2066 for active_power_l1; values should match the live readings shown in FEMS Online Monitoring.
Things to watch for
All register reads return zero or no response. What is wrong?
The FEMS Modbus/TCP Read Access app must be installed and active in the FEMS App Center. If the app is not installed, the Modbus TCP API is not enabled and all reads will fail. Install the app, confirm its status widget shows active, then retry.
The gateway connects on port 502 but energy registers return garbage values.
The cumulative energy registers (active_production_energy_l1/L2/L3) are uint32 types spanning two consecutive 16-bit holding registers. Ensure your Modbus client reads two registers per value and combines them as a big-endian 32-bit unsigned integer. Reading only one register will produce incorrect values.
Power values appear, but they do not match what FEMS Online Monitoring shows.
The FEMS Modbus channel mapping is specific to your system configuration and FEMS version. Verify the register addresses against the Modbus table downloadable from FEMS Online Monitoring under Settings, then system profile, then the Modbus TCP widget. Register offsets can shift if component IDs were changed during commissioning.
Connection drops intermittently after a few minutes of polling.
The FEMS Modbus/TCP interface requires the polling client to be on the same physical network as the FEMS controller. Routing through additional network hops or VLANs can cause timeouts. Also check that your poll interval is not below 1 second; aggressive polling has been observed to cause the FEMS Modbus API to close the connection.
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