Register 4126 always returns zero even in sunshine. Why?

The XEM470 EMC reports PV power only when a PV energy meter is correctly paired and active in the flow system. Verify in the Hager flow portal that the PV meter component is added, paired, and showing live data. If the meter is unconfigured or offline, register 4126 will read zero regardless of actual generation.

The gateway connects to the XEM470 but reads return timeout errors. What now?

The XEM470 communicates over Ethernet (Modbus TCP). Confirm the device IP is reachable from the ModbusCloud Gateway (ping test), that no firewall rule blocks TCP port 502, and that the XEM470's NET LED is solid green rather than flashing orange or red, which would indicate a network or cloud connectivity fault.

Power values look inconsistent or jump unexpectedly. What causes this?

Register 4126 is typed as uint32, spread across two consecutive 16-bit Modbus holding registers read via FC3. Ensure your Modbus client uses big-endian (high word first) byte order when assembling the 32-bit value. Incorrect word order causes the high and low words to swap, producing wildly incorrect readings that still pass range checks.

The NET LED on the XEM470 flashes orange or red. Can I still poll Modbus?

An orange or red NET LED means the EMC has lost its connection to the Hager cloud or has an IP configuration fault. Local Modbus TCP communication may still function if the device has a valid IP address, but the energy data from the PV meter may stale or freeze. Resolve the network issue first: check DHCP lease, subnet mask, and gateway settings on the XEM470 embedded webserver.

Free Modbus template: Hager Hager XEM with EMC flow R2 (pv)

Name: Hager Hager XEM with EMC flow R2 (pv)
Brand: Hager
SKU: d978cb05-b2da-4482-b03a-9c7e0c815826

The Hager XEM with EMC flow R2 (pv) is an energy management controller in the Hager flow home energy management system, used to monitor photovoltaic production in residential and light-commercial installations. The XEM470 EMC connects over Ethernet and exposes data via Modbus TCP. This template reads the PV active power register (address 4126), giving your ModbusCloud portal a live view of solar generation output. With this single measurement in the cloud, installers and building owners can track real-time PV yield, feed data into dashboards, and verify that solar generation matches design expectations.