All register values show zero or NaN. What is wrong?

The UMG806 returns float32 values encoded as two consecutive 16-bit registers in big-endian word order. Confirm your Modbus master requests two registers per value starting at the correct address and interprets them as IEEE 754 float32 with high word first. A single-register read will always return an unusable result.

The gateway connects but no data appears after import.

Check that the slave address set on the UMG806 front panel matches the unit ID configured in the ModbusCloud portal exactly. Also verify the baud rate, parity, and stop bits on the Gateway serial port match the UMG806 settings; a single mismatch prevents all register reads even though the bus is physically wired correctly.

RS-485 communication drops intermittently on a multi-device bus.

Long RS-485 runs or buses with more than two devices often require 120-ohm termination resistors at each end of the cable. Make sure the cable shield is grounded at only one point. Reversed A/B polarity on any one device will corrupt traffic for all devices on the segment.

Active power reads in kilowatts but the unit field says W. Is that correct?

The Janitza Modbus address list documents the power registers as kW at the device level, but the OpenEMS template presents the values with a W unit field. Verify the actual magnitude of readings against a known load to confirm whether a scaling factor of 1000 is applied by the integration layer before the value reaches the portal.

Free Modbus template: Janitza UMG806

Name: Janitza UMG806
Brand: Janitza
SKU: 5389d2f3-9778-45d4-bdcd-f2449829195c

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Free Modbus template: Janitza UMG806 | ModbusCloud

Registers (17)

17 read / 0 write

Name	Address	Function	Type	Unit	Access
voltage_l1 Phase-to-neutral voltage on L1, in volts.	19000	FC03	float32	V	R
voltage_l2 Phase-to-neutral voltage on L2, in volts.	19002	FC03	float32	V	R
voltage_l3 Phase-to-neutral voltage on L3, in volts.	19004	FC03	float32	V	R
current_l1 RMS current on phase L1, in amperes.	19012	FC03	float32	A	R
current_l2 RMS current on phase L2, in amperes.	19014	FC03	float32	A	R
current_l3 RMS current on phase L3, in amperes.	19016	FC03	float32	A	R
active_power_l1 Real (active) power on phase L1, in watts.	19020	FC03	float32	W	R
active_power_l2 Real (active) power on phase L2, in watts.	19022	FC03	float32	W	R
active_power_l3 Real (active) power on phase L3, in watts.	19024	FC03	float32	W	R
active_power Total three-phase active power sum, in watts.	19026	FC03	float32	W	R
reactive_power_l1 Reactive power on phase L1, in var.	19036	FC03	float32	W	R
reactive_power_l2 Reactive power on phase L2, in var.	19038	FC03	float32	W	R
reactive_power_l3 Reactive power on phase L3, in var.	19040	FC03	float32	W	R
reactive_power Total three-phase reactive power sum, in var.	19042	FC03	float32	var	R
frequency Grid frequency, typically 50 or 60 Hz.	19050	FC03	float32	Hz	R
active_consumption_energy Cumulative active energy consumed (imported), watt-hours.	19062	FC03	float32	Wh	R
active_production_energy Cumulative active energy delivered (exported), watt-hours.	19070	FC03	float32	Wh	R