Fenecon Mini PvMeter
The Fenecon Mini PvMeter is a virtual PV production meter component within the FENECON FEMS energy management system, used to report the AC output of a connected photovoltaic source. This template reads the device over Modbus TCP at address 4006 and exposes the instantaneous active power in watts. Paired with the ModbusCloud Gateway, it lets you stream live PV production data into your portal for trending, alerting, and self-consumption reporting without any additional hardware metering.
- Protocol
- Modbus TCP
- Connection
- Ethernet, Modbus TCP
- Registers
- 1, read only
- Brand
- Fenecon
- Last updated
Registers (1)
1 read, 0 write
| Name | Unit | Access | Address (Hidden until you enter your email) | Function (hidden) | Type (hidden) |
|---|---|---|---|---|---|
| active_power | W | Read |
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Use cases
- Monitor live PV active power output to verify that the solar array is producing at expected levels.
- Track production trends over days and weeks to detect gradual panel degradation or soiling.
- Alert on a sudden drop in active power during daylight hours to flag inverter or wiring faults.
- Compare measured PV active power against forecast data to evaluate system yield accuracy.
- Report site-level PV generation to building owners or facility managers via the portal dashboard.
Installation
Enable the Modbus TCP read access app on the FEMS system via the FEMS App Center in the FENECON Online Monitoring portal, then confirm that the Modbus TCP server is active on port 502.
Connect the ModbusCloud Gateway to the same LAN segment as the FEMS box, ensuring no firewall blocks TCP port 502 between the Gateway and the FEMS IP address.
In the ModbusCloud portal, add a new device, import the Fenecon Mini PvMeter template, and set the Modbus unit ID to match the meter component ID configured in FEMS (the first production meter defaults to ID 6).
Trigger a manual poll on register 4006 in the portal and confirm the returned active power value matches the live reading shown in FENECON Online Monitoring.
Things to watch for
Register 4006 returns zero even when the PV array is generating.
Confirm that the correct FEMS component ID is mapped to this meter. If multiple production meters are configured, their Modbus IDs increment from 6 upward. Poll each unit ID in sequence to identify which one holds the active PV meter data, then update the unit ID in your ModbusCloud device settings.
The gateway connects but active power readings are always shifted or wrong.
FEMS Modbus TCP uses a zero-based register addressing scheme. If your polling tool or gateway defaults to a base address of 1, all register addresses will be off by one. Set the base address to 0 in your Modbus client configuration to align with the FEMS register table.
No Modbus TCP connection can be established to the FEMS box.
Read access via Modbus TCP must be enabled through the FEMS App Center. Check that the FEMS App Modbus TCP reading is installed and active. Also verify that the FEMS box IP address is reachable from the Gateway subnet, and that port 502 is not blocked by a local router or firewall rule.
Active power values look implausibly high or fluctuate erratically.
The active_power register is a uint16 value in watts with no scaling factor applied. If the returned value appears out of range, verify that the data type in the portal template is set to uint16 and that no additional scaling multiplier has been applied. Also check that only one Modbus client polls the FEMS concurrently, as simultaneous connections can cause response errors.
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