The portal connects but both registers return zero or no data. Why?

Confirm that Modbus TCP is explicitly enabled in the XEM470 configuration and that no firewall or VLAN is blocking port 502 between the ModbusCloud Gateway and the XEM470. Some firmware versions disable the Modbus TCP server by default; check the device's communication settings and re-enable it if needed.

The power register reads an unexpected large negative or positive value. What is wrong?

Address 4138 returns a signed int32 value. If your Modbus client is treating it as an unsigned 32-bit integer, large positive values will appear instead of negative ones during charging. Verify that the data type is configured as int32 in the template, which it is by default.

The state of charge value jumps erratically between reads. How do I fix this?

Address 4146 returns a uint16 value. If you see erratic jumps, confirm the function code is 3 (read holding registers) and that only one Modbus master is polling the XEM470 at a time. Multiple simultaneous masters can cause garbled responses on some firmware revisions.

Can I rely on the power and soc registers for billing or settlement purposes?

These registers provide operational monitoring data for energy management purposes. They are not MID-certified measurement values. For billing or settlement, use the dedicated MID-certified energy meters in the Hager flow installation. Read-only access here carries no write risk, but always verify your legal metering requirements with the relevant authority.

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

The Hager XEM with EMC flow R2 is a residential energy storage system combining a battery, inverter, and the XEM470 Energy Management Controller on a single DIN-rail platform. The EMC controls PV self-consumption and coordinates the battery, EV charging stations, and grid. This Modbus TCP template reads two core battery registers: instantaneous charge or discharge power and battery state of charge. Connecting this template to the ModbusCloud Gateway gives installers and building owners continuous visibility into battery behaviour across sites without opening the Hager flow cloud.

Name	Address	Function	Type	Unit	Access
power Battery charge or discharge power, signed integer in watts.	4138	FC03	int32	W	R
soc Battery state of charge, integer percentage, 0 to 100.	4146	FC03	uint16	%	R